NASA SP-2000-4521
NASA History Division
Office of Policy and Plans
NASA Headquarters
Washington, DC 20546
February 2001
Humans to Mars
Fifty Years of Mission Planning,
1950â2000
David S. F. Portree
Monographs in Aerospace History #21
NASA SP-2001-4521
Humans to Mars
Fifty Years of Mission Planning,
1950â2000
David S. F. Portree
Humans to Mars
Fifty Years of Mission Planning,
1950â2000
by David S. F. Portree
NASA History Division
Office of Policy and Plans
NASA Headquarters
Washington, DC 20546
Monographs in Aerospace History Series
Number 21
February 2001
Library of Congress Cataloging-in-Publication Data
Portree, David S. F.
Humans to Mars: fifty years of mission planning, 1950â2000/by David S. F. Portree.
p. cm.â(Monographs in aerospace history; no. 21) (NASA publication SP)
Includes bibliographical references and index.
1. Space flight to MarsâPlanning. 2. United States. National Aeronautics and Space Administration.
I. Title. II. Series. III. NASA SP ; no. 4521.
TL799.M3 P67 2000
629.45â53âdc21
00â062218
iii
Humans to Mars: Fifty Years of Mission Planning, 1950â2000
Contents
Foreword ............................................................................................................................................................v
Preface ..............................................................................................................................................................vii
Chapter 1: On the Grand Scale ............................................................................................................................1
Chapter 2: Earliest NASA Concepts ......................................................................................................................5
Chapter 3: EMPIRE and After ............................................................................................................................11
Chapter 4: A Hostile Environment ......................................................................................................................23
Chapter 5: Apogee ............................................................................................................................................33
Chapter 6: Viking and the Resources of Mars ....................................................................................................53
Chapter 7: The Case for Mars ............................................................................................................................57
Chapter 8: Challengers ......................................................................................................................................67
Chapter 9: Space Exploration Initiative ..............................................................................................................77
Chapter 10: Design Reference Mission ..............................................................................................................89
Acronyms ........................................................................................................................................................101
Endnotes..........................................................................................................................................................103
Bibliography ....................................................................................................................................................127
About the Author ..............................................................................................................................................141
Index................................................................................................................................................................143
NASA History Monographs ..............................................................................................................................151
The planet Mars has long held a special fascination
and even mythic status for humans. While not the clos-
est planet to Earth, scientists have considered it to be
the planet that most closely resembles Earth and thus
is the other planet in our solar system most likely to
contain life. Since before the space age began, people
have wondered about the âred planetâ and dreamed of
exploring it.
In the twentieth century, robotic spacecraft and then
human space flight became a reality. Those who want-
ed to explore Mars in person felt that this might final-
ly become a reality as well. The Apollo program, which
put twelve Americans on the surface of the Moon, cer-
tainly encouraged the dreamers and planners who
wanted to send astronauts to Mars. Indeed, many peo-
ple in and out of the National Aeronautics and Space
Administration (NASA) have felt that human explo-
ration of Mars is the next logical step in human space
flight after the Moon.
Clearly, however, many obstacles have remained.
Human travel to and from Mars probably would take
many months at best. Thus the biomedical and psycho-
logical implications of such long-duration missions are
daunting. The logistics of getting enough food, water,
and other supplies to Mars are also challenging at best.
What would astronauts do once they got to Mars? How
long would they stay on the planetâs surface and how
would they survive there before returning to Earth?
The financial cost of sending humans to Mars would
almost surely be measured in billions of dollars. Aside
from technical and financial issues, there remains the
political question of why we should send humans to
Mars at all.
David Portree takes on these questions in this mono-
graph. By examining the evolution of 50 mission studies
over the past 50 years, he gives us a sense of the many
options that Mars human space flight planners in the
United States have explored.
Portree covers a wide
variety of ideas for human exploration of Mars, ranging
from Wernher von Braunâs of the 1950s to the Space
Exploration Initiative of 1989. These concepts, culled
from a much larger pool of studies, range from hugely
ambitious flotilla-style expeditions to much leaner
plans. This monograph provides historians, space policy
practitioners, and other readers with a very valuable
overview of how much planning has already been done.
If humans do go to Mars any time in the near future, it
is quite conceivable that their mission profile will
resemble one of the plans described here.
A number of people helped to produce this monograph.
In the NASA History Office, M. Louise Alstork edited
and proofread the manuscript, while Stephen J. Garber
and Nadine J. Andreassen also assisted with editing
and production. The Printing and Design Office devel-
oped the layout and handled the printing. Shawn
Flowers and Lisa Jirousek handled the design and edit-
ing, respectively, while Stanley Artis and Warren
Owens saw this work through the publication process.
This is the twenty-first in a series of special studies
prepared by the NASA History Office. The Monographs
in Aerospace History series is designed to provide a
wide variety of aerospace history investigations. These
publications are intended to be tightly focused in terms
of subject, relatively short in length, and reproduced in
an inexpensive format to allow timely and broad dis-
semination to researchers. Thus they hopefully serve as
useful starting points for others to do more in-depth
research on various topics. Suggestions for additional
publications in the Monographs in Aerospace History
series are welcome.
Roger D. Launius
Chief Historian
National Aeronautics and
Space Administrations
October 25, 2000
v
Humans to Mars: Fifty Years of Mission Planning, 1950â2000
Foreword
vii
The story of the dreams and the unbuilt space-
ships for flights to Mars should be recorded so
that in the future people can examine past
ideas of space travel just as we can examine the
unconsummated ideas of Leonardo da Vinci by
reading his notebooks. Years from now people
should be able to decide for themselves
whether they want to go to Mars or if they pre-
fer to stay earthbound. But let us not destroy
the dream, simply because we do not wish to
pursue it ourselves. (Edward Ezell, 1979)
1
In the past half century, visionary engineers have made
increasingly realistic plans for launching astronauts to
Mars to explore the planet. This monograph traces the
evolution of these plans, taking into account such fac-
tors as on-going technological advancement and our
improving knowledge of the red planet.
More than 1,000 piloted Mars mission studies were con-
ducted inside and outside NASA between about 1950
and 2000. Many were the product of NASA and indus-
try study teams, while others were the work of commit-
ted individuals or private organizations. Due to space
limitations, only 50 mission studies (one per year, or less
than 5 percent of the total) are described in this mono-
graph. The studies included are believed to be represen-
tative of most of the technologies and techniques associ-
ated with piloted Mars exploration.
2
In addition to tracing the evolution of mission concepts,
this monograph examines piloted Mars mission plan-
ning from a policy standpoint. Mars plans are affected
by their societal context and by the policies that grow
from that context. When the human species eventually
decides to send a piloted mission to Mars, the political
environment in which it develops will have at least as
much impact on its shape as technology, human factors,
and the Martian and interplanetary environments.
Hence, it stands to benefit the space technologist to
study the ways in which policy has shaped (and thwart-
ed) past Mars plans. This idea may seem obvious to
some readers, yet the history of piloted Mars mission
planning shows that this truism has often been ignored
or imperfectly understood, usually to the detriment of
Mars exploration.
This history should be seen as a tool for building
toward a future that includes piloted Mars exploration,
not merely as a chronicle of events forgotten and plans
unrealized. The author hopes to update and expand it
in 15 or 20 years so that it tells a story culminating in
the first piloted Mars mission. Perhaps a university
student reading this monograph today will become a
member of the first Mars mission crew tomorrow.
The author gratefully acknowledges the assistance pro-
vided by the following: Robert Ash, Donald Beattie,
Ivan Bekey, John Charles, Benton Clark, Aaron Cohen,
John Connolly, Mark Craig, Dwayne Day, Michael
Duke, Louis Friedman, Kent Joosten, Paul Keaton,
Geoffrey Landis, John Logsdon, Humboldt Mandell,
Wendell Mendell, George Morgenthaler, Annie Platoff,
Marvin Portree, Gordon Woodcock, and Robert Zubrin.
Thanks also to the Exploration Faithful at NASAâs
Johnson Space Center for their insights and encour-
agement these past several years. Finally, thanks to
Roger D. Launius, NASA Senior Historian, for soliciting
this work and providing overall guidance.
David S. F. Portree
Houston, Texas, September 2000
A Note on Measurement
In this monograph, measurements are given in the units
used in the original study. Tons are U.S. tons (short tons)
unless specified as metric tons. Measurements not associ-
ated with a specific study are given in the metric system.
Humans to Mars: Fifty Years of Mission Planning, 1950â2000
Preface
Will man ever go to Mars? I am sure he willâ
but it will be a century or more before heâs
ready. In that time scientists and engineers
will learn more about the physical and mental
rigors of interplanetary flightâand about the
unknown dangers of life on another planet.
Some of that information may become available
within the next 25 years or so, through the erec-
tion of a space station above the Earth . . . and
through the subsequent exploration of the
[M]oon. (Wernher von Braun, 1954)
1
Von Braun in the Desert
At the beginning of serious Mars expedition planning in
the United States stands German rocket pioneer
Wernher von Braun. From 1945 to 1950, von Braun was
interned at White Sands Proving Ground in New Mexico
with about 60 other German rocket engineers spirited
out of Nazi Germany by the U.S. Army at the end of the
Second World War. Under Hitler, they had developed the
first large liquid-propellant rocket, the V-2 missile, at the
Nazi rocket base of PeenemĂŒnde; in the United States,
they shared their missilery experience by preparing and
launching captured V-2s under Army supervision.
In 1947 and 1948, to relieve boredom, von Braun
wrote a novel about an expedition to Mars. Frederick
Ordway and Mitchell Sharpe wrote in their history
The Rocket Team that von Braunâs novel âproved
beyond doubt that its author was an imaginative sci-
entist but an execrable manufacturer of plot and dia-
log.â
2
Perhaps understandably, the novel never saw
print. In 1952, however, its appendix, a collection of
mathematical proofs supporting its spacecraft
designs and mission plan, was published in West
Germany as Das Marsprojekt. The University of
Illinois Press published the English-language edition
as The Mars Project a year later.
3
By then von Braun
and many of his German colleagues were civilian
employees of the Army Ballistic Missile Agency
(ABMA) at Redstone Arsenal in Huntsville, Alabama.
Von Braun described a Mars expedition âon the grand
scale,â with ten 4,000-ton ships and 70 crewmembers.
4
He assumed no Earth-orbiting space station assembly
base. His spacecraft were assembled from parts
launched by three-stage winged ferry rockets. Nine
hundred fifty ferry flights would be required to assem-
ble the Mars âflotillaâ in Earth orbit. Von Braun esti-
mated that each ferry rocket would need 5,583 tons of
nitric acid and alcohol propellants to place about 40
tons of cargo into orbit, so a total of 5,320,000 tons of
propellants would be required to launch all ten Mars
ships. To provide a sense of scale he pointed out that
âabout 10 per cent of an equivalent quantity of high
octane aviation gasoline was burned during the six
monthsâ operation of the Berlin Airliftâ in 1948-49.
5
Von
Braun estimated total propellant cost for launching the
expedition into Earth orbit at $500 million.
Seven vessels in von Braunâs plan were assemblages of
girders and spheres without streamlining designed for
the round-trip Mars voyage. Incapable of landing, they
featured inflatable fabric propellant tanks and person-
nel spheres. Three one-way ships would each have a
winged landing glider in place of a personnel sphere. At
the appointed time, the flotillaâs rocket engines would
ignite to put the ships on a minimum-energy Earth-to-
Mars trajectory. As Earth shrank behind, the Mars ship
crews would discard empty Earth-departure propellant
tanks and settle in for an eight-month weightless coast.
The members of the first Mars expedition would be the
first humans to see the planet up close. No robotic
explorers would precede them; von Braun did not
anticipate the technological advancements that
enabled automated explorers.
From Mars orbit they would turn telescopes toward
Marsâ equator to select a site for a surface exploration
base camp. The first Mars landing site, however, would
be determined at the time the expedition left Earth.
One landing glider would deorbit and glide to a sliding
touchdown on skids on one of the polar ice caps. Von
Braun chose the polar caps because he believed them to
be the only places on Mars where the crew could be cer-
tain of finding a smooth landing site. In von Braunâs
plan, the first people on Mars would abandon their
glider on the ice cap and conduct a heroic 4,000-mile
overland trek to the chosen base camp site on Marsâ
equator. There they would build a landing strip for the
pair of wheeled gliders waiting in orbit. This Mars
landing approach is unique to von Braunâs work.
The wheeled gliders would touch down bearing the bal-
ance of the surface exploration party, leaving a skeleton
crew in orbit to tend the seven remaining ships. As soon
as the glider wheels stopped, the explorers would
unbolt their delta wings and hoist their V-2-shaped
fuselages upright to stand on their tail fins, ready for
1
Humans to Mars: Fifty Years of Mission Planning, 1950â2000
Chapter 1: On the Grand Scale
blast off back to the ships in Mars orbit in case of emer-
gency. They would then set up an inflatable habitat,
their base of operations for a 400-day survey of Marsâ
deserts. They would gather samples of native flora and
fauna and explore the mysterious linear âcanalsâ
glimpsed through Earth-based telescopes since the late
nineteenth century. The journey back to Earth orbit
would mirror the flight to Mars. Total expedition dura-
tion would be about three years.
In almost every Mars expedition plan from von Braun
to the present, propellant has been potentially the
single heaviest expedition element. Von Braun
attempted to minimize total Mars expedition
weightâand thus the number of expensive rockets
required to launch the expedition from Earthâs sur-
faceâby reducing as much as possible the amount of
propellant needed to boost the expedition from Earth
to Mars and back again. His mission profileâa mini-
mum-energy Mars transfer, followed by a long stay
during which the planets moved into position for a
minimum-energy transfer back to Earthâwas the
chief means he used to reduce required propellant.
This approach, called a conjunction-class mission, will
be described in more detail in chapter 3. Extensive
use of inflatable fabric structures also helped reduce
spacecraft weight, though von Braun invoked them
primarily because they could be folded to fit within
the cargo bay of his hypothetical ferry rocket.
Use of multiple Mars ships and landers minimized
risk to crew. If one ship failed, its crew could transfer
to the other ships at the price of increased crowding.
Von Braunâs expedition plan boosted science return
through large crews (including professional scientists),
a small fleet of tractors for wide-ranging surface trav-
erses, and ample scientific gear. His thinking was
shaped by large Antarctic expeditions of his day, such
as Operation High Jump (1946-47), which included
4000 men, 13 ships, and 23 aircraft.
6
In the days before
satellites, Antarctic explorers were largely cut off from
the world, so experts and technicians had to be on
hand to contend with any situation that might arise.
Von Braun anticipated that Mars explorers would face
a similar situation.
In keeping with his assumption that little automation
would be available for precursor probes, von Braunâs
piloted ships were largely manually controlled, making
large, naval-style crews mandatory. Lack of automated
systems also dictated that some crewmembers remain
in Mars orbit to tend the Earth-return ships.
It is interesting to compare von Braunâs vision with the
Apollo lunar expeditions, when just two astronauts
landed on Earthâs Moon. An army of personnel, including
scientists, formed part of each Apollo expedition, but
remained behind on Earth. This separation was made
possible by communication advances von Braun did not
anticipate. In 1952 von Braun stated that television
transmission between Earth and a lunar expedition
would be impractical.
7
Sixteen years later, Neil
Armstrongâs first footsteps on the dusty, cratered Sea of
Tranquillity were televised live to 500 million people.
Collierâs
Von Braunâs slender book of proofs was not widely dis-
tributed. His vision, however, won over the editors of the
colorful Collierâs weekly magazine, who commissioned
him to write a series of space exploration articles. The
Collierâs editor for the project, Cornelius Ryan, also
solicited inputs from astronomer Fred Whipple, physicist
Joseph Kaplan, physiologist Heinz Haber, United
Nations lawyer Oscar Schachter, science writer Willy
Ley, and others. Technical and astronomical art by
Chesley Bonestell, Rolf Klep, and Fred Freeman brought
von Braunâs technical descriptions to life. Collierâs, now
defunct, had a circulation of three million, making it one
of Americaâs most popular magazines. Through the
Collierâs articles, charismatic von Braun became identi-
fied with space flight in the minds of Americansâthe
quintessential white-coated rocket scientist.
Collierâs published eight articles laying out a logical
space program blueprint. The first, published on 22
March 1952, described von Braunâs winged ferry rockets
and a spinning, wheel-shaped artificial-gravity space
station in Earth orbit.
8
Collierâs readers reached the
Moon in October 1952
9
and explored Mars in the 30
April 1954 issue.
10
Each step in von Braunâs program
built infrastructure and experience for the next.
Von Braunâs Collierâs Mars plan was identical to that
described in The Mars Project, except that the ten-ship
Mars flotilla would be assembled near an Earth-orbit-
ing space station. Again, von Braun assumed no robotic
precursors. This time, however, telescopes located on the
space station, high above Earthâs obscuring atmosphere,
2
Monographs in Aerospace History
Chapter 1: On the Grand Scale
would be used to refine knowledge of Mars and select
candidate landing sites before the expedition left Earth.
Mars plans tend to focus on spacecraft, not astronauts.
In the Collierâs Mars article, however, von Braun
explored the psychological problems of the Mars voy-
age. âAt the end of a few months,â he wrote, âsomeone is
likely to go berserk. Little mannerismsâthe way a
man cracks his knuckles, blows his nose, the way he
grins, talks or gesturesâcreate tension and hatred
which could lead to murder . . . [i]f somebody does
crack, you canât call off the expedition and return to
Earth. Youâll have to take him with you.â He also pro-
posed censoring radio communication to prevent the
crew from hearing dispiriting news about their home-
towns.
11
The Collierâs articles were expanded into a series of four
classic books. The first four chapters of the 1956 book
The Exploration of Mars
12
covered the history of Mars
observation and the then-current state of knowledge.
Wrote von Braun and his collaborator Willy Ley: âThis
is the picture of Mars at mid-century: A small planet of
which three-quarters is cold desert, with the rest cov-
ered with a sort of plant life that our biological knowl-
edge cannot encompass . . .â
13
For von Braun, life on
Mars was a given. In fact, von Braunâs Mars was not too
different from the New Mexico desert where he penned
Das Marsprojekt.
Von Braun and Ley then described the Mars expedition.
They conceded that it was âentirely possible . . . that
within a decade or so successful tests with some sort of
nuclear rocket propulsion system might be accom-
plishedâ; however, for the present, it was âexciting as
well as instructiveâ to show that humans could reach
Mars using available (1950s) technology.
14
Their Mars expedition was a cut-price version of the
1952 Das Marsprojekt/1954 Collierâs expedition, with
just 12 crewmembers in two ships. Four hundred
launches would put the parts, propellants, and supplies
needed for the expedition into Earth orbit at the rate of
two launches per day over seven months.
A single-passenger ship would complete the round-
trip voyage. The craft would have an inflatable per-
sonnel sphere 26 feet across, with a control room on
deck one and living quarters on decks two and three.
The one-way cargo ship would carry the expeditionâs
single 177-ton landing glider in place of a personnel
sphere. The ships together would weigh 3,740 tons
before departing Earth orbit; the passenger ship
would weigh only 38.4 tons when it returned to Earth
orbit alone at the end of the expedition.
Upon reaching Mars, the crew would turn powerful
telescopes toward proposed equatorial landing sites
selected using telescopes on the space station.
Equatorial sites were preferred, von Braun and Ley
wrote, because they would be warmest. Citing the
many kinds of surface features nearbyâincluding
two of the mysterious canalsâthey proposed as
prime landing site candidate Margaritifer Sinus, a
dark region visible in Earth-based telescopes.
15
The
glider would descend to Mars with nine crewmem-
bers on board (leaving three in orbit to mind the pas-
senger shipâs systems) and land on skids at about 120
miles per hour.
After the glider stopped, the intrepid explorers would
walk out onto the wing, leap 18 feet to the ground (the
equivalent of a six-foot drop in Earth gravity), and
immediately prepare the ship for emergency liftoffâ
this despite having just spent eight months in weight-
lessness. They would remove the wings and use the
expeditionâs two caterpillar tractors to hoist the bul-
let-shaped fuselage upright. They would then inflate a
20-foot hemispherical pressurized âtentâ to serve as
expedition headquarters.
After a year of Mars surface exploration, they would lift
off, rejoin their compatriots in orbit, and blast for
Earth. The last drops of propellants would place the
ship in a 56,000-mile-high Earth orbit. A relief ship
would ascend from the space station to collect the crew;
they would abandon the Mars ship as a monument to
the early days of planetary exploration.
Mars Beckons
Every 26 months, the orbits of Earth and Mars bring
the two planets relatively close together. At such times
Mars becomes a bright red-orange âstarâ in Earthâs
skies. Because Mars appears opposite the Sun in the
sky when it is closest to Earth, astronomers call such
events oppositions.
Chapter 1: On the Grand Scale
3
Humans to Mars: Fifty Years of Mission Planning, 1950â2000
Mars has an elliptical orbit, so its distance from Earth
at opposition varies. The best oppositions, when Earth
is closest to Mars while the planet is closest to the Sun,
occur roughly every 15 years. During the best opposi-
tions, Marsâ disk appears about twice as large in tele-
scopes as during the poorest oppositions, when Mars is
farthest from the Sun.
In the 1950s, all knowledge of Marsâ conditions came
from telescopic observations made during the best
oppositions. Since the invention of the telescope in the
early seventeenth century, astronomers eagerly await-
ed the best oppositions to attempt to pry new secrets
from Mars. For example, the canals were first seen dur-
ing the excellent 1877 opposition. When the first print-
ing of The Exploration of Mars arrived on bookstore
shelves, astronomers were eagerly awaiting the close
opposition of September 1956.
The year 1956 marked the last âbestâ Mars opposition
upon which astronomers would entirely depend for
data, because humanityâs relationship with Mars was
about to change. A year after that Mars opposition, on
4 October 1957, the Soviet Union launched Sputnik 1
into Earth orbit. Von Braunâs U.S. Army rocket team
launched the American response, Explorer 1, on 31
January 1958. By 1971, when again Mars shone as
brightly in Earthâs skies as in 1956, spacecraft recon-
naissance had revolutionized how we learn about the
solar system. As we will see in the coming chapters,
the 1956 and 1971 âbestâ oppositions neatly bracketed
the early heyday of NASA Mars exploration planning.
4
Monographs in Aerospace History
Chapter 1: On the Grand Scale
Now it is time to take longer stridesâtime for
a great new American enterpriseâtime for this
nation to take a clearly leading role in space
achievement . . . I believe that this nation
should commit itself to achieving the goal,
before this decade is out, of landing a man on
the [M]oon and returning him safely to Earth.
No single space project in this period will be
more impressive to mankind, or more impor-
tant for the long-range exploration of space . . .
it will not be one man going to the [M]oonâit
will be an entire nation. For all of us must work
to put him there. (John F. Kennedy, 1961)
1
NASAâs First Mars Study
As early as November 1957âa month after Sputnik 1
became Earthâs first artificial moonâabout 20
researchers at Lewis Research Center, a National
Advisory Committee on Aeronautics (NACA) laborato-
ry in Cleveland, Ohio, commenced research into
nuclear-thermal and electric rocket propulsion for
interplanetary flight.
2
(Lewis was renamed Glenn
Research Center at Lewis Field in 1999.) Such
advanced propulsion systems required less propellant
than chemical rockets, thus promising dramatic space-
craft weight savings. This meant fewer costly launches
from Earthâs surface and less Earth-orbital assembly.
Soon after the Lewis researchers began their work,
Congress and the Eisenhower administration began to
work toward the creation of a U.S. national space
agency in response to Soviet space challenges.
President Dwight Eisenhower wanted a civilian agency
to ensure that headline-grabbing space shots would not
interfere with the serious business of testing missiles
and launching reconnaissance satellites. Senator
Clinton Anderson (Democrat-New Mexico) led a faction
that wanted the Atomic Energy Commission (AEC) to
run the space program, citing as justification its
nuclear-thermal rocket experiments. Others supported
expansion of NACA, the federal aeronautics research
organization founded in 1915. On 29 July 1958,
Eisenhower signed into law legislation creating the
National Aeronautics and Space Administration
(NASA) from NACA and various Department of
Defense space organizations.
3
When NASA opened its doors on 1 October 1958, Lewis
became a NASA Center. The Lewis researchers sought
to justify and expand their advanced propulsion work.
In April 1959âtwo years before any human ventured
into Earth orbitâthey testified to Congress about their
work and solicited funding for a Mars expedition study
in Fiscal Year (FY) 1960. Congress granted the request,
making the Lewis study the first Mars expedition
study conducted under NASA auspices.
4
The Lewis researchers sought to develop weight esti-
mates for Mars ships using their advanced propulsion
systems. For their nuclear-thermal rocket analysis, the
Lewis researchers assumed a Mars mission profile that
would, by the end of 1960s, come to be virtually the
standard NASA model:
The mission begins with the vehicle system
in an orbit about the Earth. Depending on the
weight required for the mission, it can be
inferred that the system has been delivered as
a unit to orbitâor that it has been assembled
in the orbit from its major constituents . . . the
vehicle containing a crew of seven men is
accelerated by a high-thrust nuclear rocket
engine onto the transfer trajectory to Mars.
Upon arrival at Mars, the vehicle is decelerat-
ed to establish an orbit about the planet . . . a
Mars Landing Vehicle containing two men
descends to the Martian surface . . . . After a
period of exploration these men take off from
Mars using chemical-rocket power and effect a
rendezvous with the orbit party. The . . . vehi-
cle then accelerates onto the return trajectory;
and, upon reaching Earth, an Earth Landing
Vehicle separates and . . . decelerates to return
the entire crew to the surface.
5
For analysis purposes, the Lewis researchers targeted
the 1971 launch opportunity, when Marsâ close prox-
imity to Earth minimized the amount of energy (and
thus propellant) needed to reach it. They cautioned,
however, that â[t]his is not meant to imply that actual
trips are contemplated for this period.â
6
They opted for
a 420-day round trip with a 40-day stay at Mars, and
found that the optimum launch date was 19 May 1971.
As might be expected, fast Mars trips generally
require more propellant (typically liquid hydrogen in
the case of a nuclear rocket) than slow trips. The
more propellant required, the greater the spacecraftâs
weight at Earth-orbit departure. Thus, longer mis-
sions appear preferable if weight minimization is the
5
Humans to Mars: Fifty Years of Mission Planning, 1950â2000
Chapter 2: Earliest NASA Concepts
dominant consideration in a Mars mission plan. The
Lewis team noted, however, that crew risk factors
had to be considered in calculating spacecraft weight.
These were hard to judge because much about condi-
tions in interplanetary space and on Mars remained
unknown.
In particular,
they cautioned that
â[c]urrent knowledge of radiation hazards is still not
completely satisfactory.â
7
Explorer 1 and Explorer 3 (launched 26 March 1958)
detected the Van Allen Radiation Belts surrounding
Earth. Their discovery was the first glimpse of an
unsuspected reef, rock, or shoal menacing navigators in
the new ocean of space. It raised the profile of ionizing
radiation as a possible threat to space travelers.
No longer were the thin-skinned personnel spheres
of von Braunâs 1950s Mars ships judged adequate.
Von Braun had made little provision for limiting
crew radiation exposure, though he had expressed
the hope that âby the time an expedition from earth
is ready to take off for Mars, perhaps in the mid-
2000s . . . researchers will have perfected a drug
which will enable men to endure radiation for com-
paratively long periods.â
8
The Lewis team did not place its trust in pharmacolo-
gy. For their study, they assumed the following ioniz-
ing radiation sources: the Van Allen belts at Earth
and Mars (in reality, Mars lacks radiation belts), con-
tinuous cosmic ray bombardment, solar flares, and, of
course, the shipâs nuclear-thermal rocket engine.
Their spacecraft crew compartment, an unshielded
two-deck cylinder providing 50 square feet of floor
space per crewmember (âbetween that provided for
chief petty officers and commissioned officers on sub-
marinesâ), contained a heavily shielded cylindrical
âvaultâ at its center, into which the crew would retreat
during passage through the Van Allen belts, nuclear
rocket operation,
and large solar flares.
9
Crewmembers would also sleep in the vault; this
would reduce their cosmic ray exposure during
approximately one-third of each day.
Not surprisingly, the weight of radiation shielding
required depended on how much radiation exposure for
the crew was allowed. If major solar flares could be
avoided during the 420-day voyage and a total radia-
tion dose of 100 Roentgen Equivalent Man (REM) were
permissible, then 23.5 tons of shielding would suffice,
the Lewis researchers found. If, however, one major
flare could not be avoided, shielding weight jumped to
82 tons to keep the total dose below 100 REM. If only
50 REM were considered permissible and one major
flare could not be avoided, shielding weight would
become âenormousââ140 tons.
10
âThese data,â they
wrote, served âto underscore . . . the importance of
determining more precisely the nature and virulence of
the radiation in space.â
11
The Lewis researchers determined that âshort trips
are as, or more, economical, in terms of weight, than
long-duration missions,â even though they generally
required more propellant, because long trips
required more heavy shielding to keep the crew
within the radiation dose limit.
12
They estimated
that a nuclear-thermal spaceship for a 420-day
round trip in 1971 with a maximum allowable total
radiation dose of 100 REM would weigh 675 tons at
Earth-orbit launch.
Twirling Ion Ships to Mars
Just as the creation of NASA was prompted by the Cold
War clash between the United States and the Soviet
Union, so was the goal that dominated NASAâs first
decade. On 12 April 1961, Soviet cosmonaut Yuri
Gagarin became the first person to orbit Earth. His
Vostok 1 spacecraft completed one circuit of the planet
in about 90 minutes. Gagarinâs flight was a blow to the
new administration of President John F. Kennedy, who
had narrowly defeated Eisenhowerâs Vice President,
Richard M. Nixon, in the November 1960 elections.
Gagarinâs flight coincided with the embarrassing fail-
ure of a Central Intelligence Agency (CIA)-sponsored
invasion of Cuba at the Bay of Pigs (17-19 April 1961).
13
The tide of Kennedyâs political fortunes began to turn
on 5 May 1961, when astronaut Alan Shepard rode the
Freedom 7 Mercury capsule on a suborbital hop into the
Atlantic Ocean. On 25 May 1961, Kennedy capitalized
on this success to seize back the political high ground.
Before a special Joint Session of Congress, he called for
an American to land on Earthâs Moon by the end of the
1960s.
NASA had unveiled a 10-year plan in February 1960
that called for a space station and circumlunar flight
before 1970, and a lunar landing a few years later. The
6
Monographs in Aerospace History
Chapter 2: Earliest NASA Concepts
Agency believed that this constituted a logical program
of experience-building steps.
14
Mars planners were torn
over Kennedyâs new timetable. On the one hand, it put
Mars work on the back burner by making the Moon
NASAâs primary, overriding goal. On the other hand, it
promised to make launch vehicles and experience need-
ed for Mars available all the sooner.
15
Two contenders led the pack of Apollo lunar mission
modes in mid-1961âEarth-Orbit Rendezvous (EOR)
and Direct Ascent. Both stood to benefit piloted Mars
missions. In EOR, two or three boosters launched Moon
ship modules into Earth orbit. The modules docked;
then the resultant ship flew to the Moon and landed.
Mars planners knew that experience gained through
Moon ship assembly could be applied to Mars ship
assembly. In Direct Ascent, the spacecraft flew directly
from Earthâs surface to the lunar surface and back.
This called for an enormous launch vehicle which could
be used to reduce the number of launches needed to put
Mars ship parts and propellants into orbit.
NASAâs Marshall Space Flight Center in Huntsville,
Alabama, was responsible for developing the rockets
required for lunar flight. Marshall began as the
ABMAâs Guided Missile Development Division. In the
1950s, the von Braun rocket team had developed some
of the first U.S. missiles, including the intermediate-
range Redstone, the âAmericanizedâ version of the V-2.
A Redstone variant called Jupiter-C launched the
Explorer 1 satellite.
Just as Saturn was next after Jupiter among the plan-
ets, the Saturn series of rockets was next after Jupiter-
C. Saturn I and Saturn IB used a cluster of
Redstone/Jupiter tanks in their first stages. The engi-
neers in Huntsville envisioned yet larger rockets.
NASAâs 1960 master plan called for development of an
enormous âpost-Saturnâ rocket called Nova. Either
Saturn or Nova could be used to carry out an EOR
Moon mission; Nova was required for Direct Ascent.
Marshall might have performed the first NASA Mars
study, but when the Lewis advanced propulsion engi-
neers testified to Congress in 1959, the Huntsville
organization was still not a part of NASA. Ernst
Stuhlingerâs group within the ABMA Guided Missile
Development Division had commenced work on electric
propulsion in 1953 and considered Mars expeditions in
its design process.
In electric propulsion, a thruster applies electricity to
propellant (for example, cesium), converting its atoms
into positive ions. That is, it knocks an electron off each
cesium atom, giving it an electric charge. The thruster
then electrostatically âgripsâ the cesium ions and
âthrowsâ them at high speed. Electric propulsion pro-
vides constant low-thrust acceleration while expending
much less propellant than chemical or nuclear-thermal
propulsion, consequently reducing spacecraft weight.
Low thrust, however, means low acceleration.
Stuhlinger presented a paper in Austria in 1954
describing a solar-powered electric-propulsion space-
craft with dish-shaped solar concentrators.
16
Walt
Disney had contacted von Braun after reading the
Collierâs articles; this contact led to three space flight
television programs from 1955 to 1957. Disneyâs Mars
and Beyond, which premiered on 4 December 1957, fea-
tured Stuhlingerâs distinctive umbrella-shaped
nuclear-electric Mars ships, not von Braunâs sphere-
and-girder chemical ships.
17
The U.S. Army, eager to retain its foothold in mis-
silery, was loath to release the von Braun team to
NASA as required by President Eisenhower. Army
resistance prevented von Braun, Stuhlinger, and their
colleagues from officially joining the new space
agency until 1 July 1960. However, they had by then
worked directly with NASA for some timeâhence
their input to NASAâs February 1960 master plan.
18
Wernher von Braun became Marshallâs first director,
and Ernst Stuhlinger became director of Marshallâs
Research Projects Division.
Stuhlingerâs 1962 piloted Mars mission design, target-
ed for launch in the early 1980s, would include five 150-
meter long Mars ships of two typesââAâ and âBââeach
carrying three astronauts.
19
As in von Braunâs The
Mars Project, risk to crew was minimized through
redundancy. The expedition could continue if as many
as two ships were lost, provided they were not of the
same type. One ship could return the entire 15-person
expedition to Earth under crowded conditions.
The three âAâ ships would carry one 70-ton Mars lander
each. At Mars, an unpiloted cargo lander would detach;
if it landed successfully, the explorers would land in the
second lander. If the cargo lander failed, the second lan-
der would become an unpiloted cargo lander, and the
third lander would deliver the surface team. The lander
Chapter 2: Earliest NASA Concepts
7
Humans to Mars: Fifty Years of Mission Planning, 1950â2000
crew would stay on Mars for 29 days. If the crew lander
ascent stage failed to fire, the explorers could return to
Mars orbit in the cargo lander ascent stage.
Stuhlingerâs ships would each include a nuclear reactor
producing 115 megawatts of heat. The reactor would
heat a working fluid which would drive a turbine; the
turbine in turn would drive a generator to supply 40
megawatts of electricity to two electric-propulsion
thrusters. To reject the heat it retained after leaving
the turbine, the working fluid would circulate through
radiator panels with a total area of 4,300 square
meters before returning to the reactor. The ship would
move through space with its radiator panels edge-on to
the Sun. Radiator tubes would be designed to be indi-
vidually closed off to prevent a meteoroid puncture
from releasing all of the shipâs working fluid into space.
Each flat, diamond-shaped ship would weigh 360 tons
when it switched on its electric thrusters in Earth orbit
at the start of the Mars voyageâa little more than half
as much as the NASA Lewis nuclear-thermal Mars
ship. Of this, 190 tons (for the âBâ ships) or 120 tons (for
the âAâ ships) would be cesium propellant. As already
indicated, the price of low spacecraft weight was low
accelerationâStuhlingerâs fleet would need 56 days to
spiral up and out of Earth orbit; then, after a 146-day
Earth-Mars transfer, it would require 21 days to spiral
down to low-Mars orbit.
Stuhlingerâs ships would rotate 1.3 times per minute to
produce acceleration equal to one-tenth of Earthâs grav-
ity in the crew cabin. The reactor, located at the oppo-
site end of the ship from the crew cabin, would act as
an artificial gravity counterweight. Thus, the separa-
tion needed to keep the crew away from the reactor
would also serve to increase spin radius.
Engineers designing artificial gravity systems must
endeavor to make the spin radius as long as possible.
This is because an artificial gravity system with a short
spin radius must rotate more rapidly than one with a
long spin radius to generate the same level of accelera-
tion, which the crew feels as gravity. A short-radius,
fast-spinning rotating system produces pronounced
coriolis effects. For example, water leaving a faucet
curves noticeably. Similarly, a person moving toward or
away from the center of such a rotating system tends to
veer sideways. Turning the head tends to produce nau-
sea. In addition, a troublesome gravity gradient occurs
vertically along the bodyâthe head experiences less
acceleration than the feet.
Stuhlingerâs electric thrusters would be mounted at the
shipâs center of rotation on stalks. These would rotate
against the shipâs spin to remain pointed in the
required direction. In addition to aiding the crew,
Stuhlinger noted, artificial gravity would prevent gas
pockets from forming in the working fluid.
20
Stuhlingerâs design included a 50-ton, graphite-clad
radiation shelter (about 15 percent of the entire
weight of the ship) in the shipâs crew compartment.
Drinking water, propellant, oxygen cylinders, and
equipment would be arranged around the shelter to
provide additional shielding. The 2.8-meter-diameter,
1.9-meter-high shelter would hold a three-person
shipâs complement comfortably and would protect the
entire 15-person expedition complement in an emer-
gency. The crew would live in the shelter for 20 days
during the outbound Van Allen belt crossing.
The Moon Intervenes
Stuhlinger wrote that it âis generally accepted that a
manned expedition to . . . Mars will be carried out soon
after such an ambitious project becomes technically
feasible . . . [it is] the natural follow-on project to be
undertaken after the lunar program.â
21
Mars planners
took Kennedy at his word when he said that reaching
the Moon was âimportant for the long-range explo-
ration of space.â
On 11 July 1962, however, NASA announced that it
had selected Lunar Orbit Rendezvous (LOR) over EOR
and Direct Ascent as the Apollo mission mode.
Attention had turned from EOR and Direct Ascent to
LOR early in 1962. LOR, a concept zealously promoted
by NASA Langley Research Center engineer John
Houbolt, promised the lowest lunar spacecraft
weight. This enabled a lunar expedition with only a
single Saturn rocket launch, making LOR the
fastest, cheapest way of meeting Kennedyâs end-of-
decade deadline.
22
In LOR, the lunar spacecraftâwhich consists of a small
lander and a command shipâblasts off directly from
Earth with no Earth-orbital assembly. The lander lands
on the Moon, leaving the large command ship in lunar
8
Monographs in Aerospace History
Chapter 2: Earliest NASA Concepts
orbit. Surface exploration completed, the lander blasts
off from the Moon and returns to the orbiting command
ship. Spacecraft weight is reduced because only the
small, light-weight lander must burn propellant to land
and lift off.
It should be noted that the NASA Lewis and
Stuhlinger Mars plans used the same general
approach for the same reason. Landing the entire
massive ship on Mars and launching it back to Earth
would require impossible amounts of propellant or an
impossibly small interplanetary vehicle. The standard
NASA Mars plan can thus be dubbed Mars Orbit
Rendezvous (MOR).
The LOR decision impacted post-Apollo ambitions.
The reduction in lunar expedition mass promised by
LOR removed the need for a post-Saturn Nova rocket,
as well as the need to learn how to assemble large
modular vehicles in Earth orbit. It thus reduced
Apolloâs utility as a technological stepping stone to
Mars. The need to create a new justification for big
rockets influenced Marshallâs decision to start a new
Mars study in early summer 1962. As will be seen in
the next chapter, this study, known as EMPIRE,
kicked off the most intense period of piloted Mars mis-
sion planning in NASAâs history.
9
Humans to Mars: Fifty Years of Mission Planning, 1950â2000
Chapter 2: Earliest NASA Concepts
Manned exploration of Mars is the key mis-
sion in interplanetary space flight. Man must
play a key role in the exploration of Mars
because the planet is relatively complex,
remote, and less amenable to exploration by
unmanned probes than is the [M]oon . . . seri-
ous interest in the Manned Mars Mission is
springing up . . . with many planning studies
being performed by several study teams
within [NASA] and within industry . . . .
Perhaps the most important result emerging
from the present studies is the indication
that the Manned Mars Mission can be per-
formed in the relatively near future with
equipment and techniques that will for the
most part be brought into operation by the
Apollo Project . . . the Manned Mars Mission
is rapidly taking shape as the direct follow-
on to the Apollo Project. (Robert Sohn, 1964)
1
EMPIRE
Ernst Stuhlingerâs Research Projects Division was the
smaller of two advanced planning groups in ABMA.
The larger, under Heinz Koelle, became the Marshall
Space Flight Centerâs Future Projects Office. Until
1962, Koelleâs group focused primarily on lunar pro-
gramsâKoelle was, for example, principal author of
the U.S. Armyâs 1959 Project Horizon study, which
planned a lunar fort by 1967. Koelleâs deputy, Harry
Ruppe, also supervised a limited number of Mars stud-
ies. Ruppe had come from Germany to join the von
Braun team in Huntsville in 1957.
In the 1962-1963 period, however, the Future Projects
Office spearheaded NASAâs Mars planning efforts. As
discussed in the last chapter, Marshallâs primary focus
was on launch vehicles. Advanced planning became
important at Marshall in part because of the long lead
times associated with developing new rockets.
Marshall director von Braun foresaw a time in the mid-
1960s when his center might become idle if no goals
requiring large boosters were defined for the 1970s. As
T. A. Heppenheimer wrote in his 1999 book The Space
Shuttle Decision,
The development of the Saturn V set the pace
for the entire Apollo program. This Moon
rocket, however, would have to reach an
advanced state of reliability before it could be
used to carry astronauts. The Marshall staff
also was responsible for development of the
smaller Saturn IB that could put a piloted
Apollo spacecraft through its paces in Earth
orbit. Because both rockets would have to
largely complete their development before
Apollo could hit its stride, von Braun knew
that his [C]enter would pass its peak of activ-
ity and would shrink in size at a relatively
early date. He would face large layoffs even
while other NASA [C]enters would still be
actively preparing for the first mission to the
Moon.
2
Mars was an obvious target for Marshallâs advanced
planning. Von Braun was predisposed toward Mars
exploration, and landing astronauts on Mars provided
ample scope for his Center to build new large boosters.
The timing, however, was not good. The Moon would, if
all went well, be reached by 1970âbut NASA would
certainly not be ready to land astronauts on Mars so
soon. For one thing, planners needed more data on the
Martian environment before they could design landers,
space suits, and other surface systems. What Marshall
needed was some kind of short-term interim program
that answered questions about Mars while still provid-
ing scope for new rocket development.
A 1956 paper by Italian astronomer Gaetano Crocco,
presented at the Seventh International Astronautical
Federation Congress in Rome, offered a possible way
out of Marshallâs dilemma.
3
Crocco demonstrated
that a spacecraft could, in theory, fly from Earth to
Mars, perform a reconnaissance Mars flyby, and
return to Earth. The spacecraft would fire its rocket
only to leave Earthâit would coast for the remainder
of the flight. The Mars flyby mission would require
less than half as much energyâhence propellantâas
a minimum-energy Mars stopover (orbital or landing)
expedition. This meant a correspondingly reduced
spacecraft weight. Total trip time for a Crocco-type
Mars flyby was about one year; for the type of mission
von Braun employed in The Mars Project (1953), trip
time was about three years.
Flyby astronauts would be like tourists on a tour bus,
seeing the sights from a distance in passing but not get-
ting off. Crocco wrote that they would use âa telescope
of moderate aperture . . . to reveal and distinguish nat-
ural [features] of the planet . . . .â He found, however,
that Marsâ gravity would deflect the flyby spacecraftâs
11
Humans to Mars: Fifty Years of Mission Planning, 1950â2000
Chapter 3: EMPIRE and After
course so it missed Earth on the return leg if it flew
closer to Mars than about 800,000 miles. Such a distant
flyby would, of course, âfrustrate the exploration scope
of the trip.â
To permit a close flyby without using propellant, Crocco
proposed that the close Mars flyby be followed by a
Venus flyby to bend the craftâs course toward Earth.
The Venus flyby would be an exploration bonus, Crocco
wrote, allowing the crew to glimpse âthe riddle which is
concealed by her thick atmosphere.â Crocco calculated
that an opportunity to begin an Earth-Mars-Venus-
Earth flight would occur in June 1971.
4
From a vantage point at the start of the twenty-first
century, a piloted planetary flyby seems a strange
notion, yet in the 1960s NASA gave nearly as much
attention to piloted Mars flybys as it did to piloted
Mars landings. Piloted Mars flybys are now viewed
from the perspective of more than three decades of suc-
cessful automated flyby missions (as well as orbiters
and landers). Of the nine planets in the solar system,
only Pluto has not been subjected to flyby examination
by machines. Robots can do flybys, so why entail the
expense and risk to crew of piloted flybys?
Indeed, there were critics at the time the Future
Projects Office launched its Early Manned Planetary-
Interplanetary Roundtrip Expeditions (EMPIRE) pilot-
ed flyby/orbiter study. For example, Maxime Faget,
principal designer of the Mercury capsule, coauthored
an article in February 1963 which pointed out that a
piloted Mars flyby would âdemand the least [propul-
sive] energy . . . but will also have the least scientific
valueâ because of the short period spent near Mars. He
added that data on Mars gathered through a piloted
flyby would be âin many ways no better than those
which might be obtained with a properly operating,
rather sophisticated unmanned probe.â
5
The key phrase in Fagetâs criticism is, of course, âprop-
erly operating.â When the Future Projects Office
launched EMPIRE in May-June 1962, robot probes did
not yet possess a respectable performance record. The
Mariner 2 probe carried out the first successful flyby
exploration of another planet (Venus) in December
1962, midway through the EMPIRE study, but the
other major U.S. automated effort, the Ranger lunar
program, was off to a shaky start. That series did not
enjoy its first success until Ranger 7 in July 1964. The
first successful Mars flyby did not occur until a year
after that. In fact, one of the early justifications for
piloted flybys was that the astronauts could act as care-
takers for a cargo of automated probes to keep them
healthy until just before they had to be released at the
target planet.
Faget also believed that the âoverall planning of a total
spaceflight program should be based on a logical series
of steps.â Mercury and Gemini would provide basic expe-
rience in living and working in space, paving the way for
Apollo, which would, Faget explained, âhave the first real
mission.â After that, NASA should build an Earth-orbit-
ing space station and possibly a lunar base.
6
For Faget, a piloted Mars flyby mission in the 1970s
was a deviation from the model von Braun popularized
in the 1950s, which placed the first Mars expedition a
century or more in the future. Faget avoided mention-
ing, however, that he had already been compelled to
rationalize Kennedyâs politically motivated drive for
the Moon. Going by von Braunâs logical blueprint, pilot-
ed lunar flight should have been postponed until after
the Earth-orbiting space station was in place.
For the EMPIRE study, three contractors studied pilot-
ed flyby and âcaptureâ (orbiter) expeditions to Mars and
Venus. Aeronutronic studied flybys
7
; Lockheed looked at
flybys and, briefly, orbiters
8
; and General Dynamics
focused on orbiter missions.
9
Aeronutronicâs study
summed up EMPIREâs three goals:
âą
Establish a requirement for the Nova rocket
development program.
âą
Provide inputs to the joint AEC-NASA nuclear
rocket program, which had been established in
1960 and included a flight test program over
which Marshall had technical direction.
âą
Explore advanced operational concepts neces-
sary for flyby and orbiter missions.
10
The first two goals were contradictory as far as spacecraft
weight minimization was concerned. Seeking justifica-
tion for a new large rocket provided little incentive for
weight minimization, while one of the great attractions of
nuclear-thermal rockets was their increased efficiency
over chemical rockets, which helped minimize weight.
The contractorsâ tendency not to tightly control spacecraft
weight assisted them with crew risk minimization. For
example, all three contractors saw fit to include in their
12
Monographs in Aerospace History
Chapter 3: EMPIRE and After
EMPIRE designs heavy spacecraft structures for gener-
ating artificial gravity.
Lockheed identified two main Mars flyby trajectory
classes, which it nicknamed âhotâ and âcool.â In the for-
mer, the piloted flyby spacecraft would drop inside
Earthâs orbit (in some launch windows Venus flyby
occurred), reach its farthest point from the Sun (aphe-
lion) as it flew by Mars, and return to Earth about 18
months after launch. In the latter, the flyby spacecraft
would fly out from Earthâs orbit, pass Mars about 3
months after launch, reach aphelion in the Asteroid
Belt beyond Mars, and return to Earth about 22
months after launch.
The Aeronutronic team opted for a âhotâ trajectory.
They assumed a Nova rocket capable of lifting 250 tons
to Earth orbit. For comparison, the largest planned
Saturn rocket, the Saturn C-5 (as the Saturn V was
known at this time) was expected to launch around 100
tons. One Nova rocket would thus be able to launch the
entire 187.5-ton Aeronutronic flyby spacecraft into
Earth orbit.
Aeronutronicâs âdesign point missionâ had the flyby
spacecraft leaving Earth orbit between 19 July 1970
and 16 August 1970, using a two-stage nuclear-thermal
propulsion system. Aeronutronicâs design retained the
empty second-stage hydrogen propellant tanks to help
shield the command center in the shipâs core against
radiation and meteoroids. Two cylindrical crew com-
partments would deploy from the core on booms; then
the ship would rotate to provide artificial gravity. An
AEC-developed radioisotope power source would
deploy on a boom behind the ship. At the end of the
flight the crew would board a lifting body Earth-return
vehicle and separate from the ship. A two-stage retro-
rocket package would slow the lifting body to a safe
Earth atmosphere reentry speed while the abandoned
flyby ship sailed by Earth into orbit around the Sun.
Lockheed also emphasized a rotating design for its
EMPIRE spacecraft. In the companyâs report, the flyby
crew rode into orbit on a Saturn C-5 in an Apollo
Command and Service Module (CSM) perched atop a
folded, lightweight flyby spacecraft. A nuclear upper
stage would put the CSM and flyby ship on course for
Mars. The CSM would then separate and the flyby
spacecraft would automatically unfold two long booms
from either side of a hub. The CSM would dock at the
end of one boom to act as counterweight for a cylindrical
habitation module at the end of the other boom. When
the ship rotated, the CSM and habitation module would
experience acceleration the crew would feel as gravity.
The weightless hub at the center of rotation would con-
tain chemical rockets for course correction propulsion,
a radiation shelter, automated probes, and a dish-
shaped solar power system. At Mars, the crew would
stop the spacecraftâs rotation and release the probes. At
journeyâs end, the crew would separate from the flyby
craft in the CSM, fire its rocket engine to slow down,
discard its cylindrical Service Module (SM), and re-
enter Earthâs atmosphere in the conical Command
Module (CM). The abandoned flyby craft would fly past
Earth into solar orbit. Lockheedâs report mentioned
briefly how a Mars orbiter mission might investigate
the Martian moons Phobos and Deimos.
11
The General Dynamics report was by far the most
voluminous and detailed of the three EMPIRE entries,
reflecting a real passion for Mars exploration on the
part of Krafft Ehricke, its principal author. Ehricke
commanded tanks in Hitlerâs attack on Moscow before
joining von Braunâs rocket team at PeenemĂŒnde. He
came to the U.S. in 1945 with the rest of the von Braun
team but left in 1953 to take a job at General Dynamics
in San Diego, California. There he was instrumental in
Atlas missile and Centaur upper-stage development. In
the late 1950s he became involved in General
Dynamics advanced planning.
Ehrickeâs team looked at piloted Mars orbiter missions.
These would permit long-term study of the planet from
close at hand, thus answering critics who complained
that piloted flybys would spend too little time near
Mars. General Dynamicsâ 450-day Mars orbiter mission
was set to launch in March 1975.
Modularized Mars ships would travel in âconvoysâ
made up of at least one crew ship and two automated
service ships. Ship systems would be âstandardized as
much as practicalâ so that the crew ship could can-
nibalize the service ships for replacement parts. If a
meteoroid perforated a propellant tank, for example,
the crew would be able to replace it with an identical
tank from a service ship. The ships would carry small
âtugboatâ spacecraft for moving propellant tanks and
other bulky spares.
12
This approachâproviding many
Chapter 3: EMPIRE and After
13
Humans to Mars: Fifty Years of Mission Planning, 1950â2000
sparesâhelped minimize risk to crew, but would dra-
matically boost overall expedition weight.
General Dynamics described many possible ship con-
figurations; what follows was typical. The company
allotted a nuclear propulsion stage for each major
maneuver. After performing its assigned maneuver, the
stage would be cast off. Ehrickeâs team estimated that
nuclear engine flight testing would have to occur
between May 1968 and April 1970 to support a March
1975 expedition. The M-1 engine system would perform
Maneuver-1 of the Mars expedition, escape from Earth
orbit (hence its designation). The M-2 engine system
would slow the ship so Marsâ gravity could capture it
into Mars orbit, and M-3 would launch the spacecraft
out of Mars orbit toward Earth. The M-4 engine system
would slow the ship at Earth at the expeditionâs end.
Attached to the front of the M-4 stage would be the 10-
foot-diameter, 75-foot-long spine module, or âneck,â
which served two functions: in addition to separating
the astronauts from the nuclear engines to minimize
crew radiation exposure, it would place distance
between the crew and the shipâs center of gravity, mak-
ing the artificial gravity spin radius longer.
General Dynamics opted arbitrarily for providing arti-
ficial gravity equal to 25 percent of Earthâs surface
gravity and estimated that five rotations per minute
was the upper limit for crew comfort. As engine sys-
tems were cast off, however, the shipâs center of rotation
would shift forward. For example, before the M-1
maneuver it would be at the aft end of the M-2
engine system, 420 feet from the shipâs nose, and at
the start of the M-2 maneuver it would be at the
front of the M-2 system, 265 feet from the nose. As
the ship grew progressively shorter, the spin radius
would decrease, forcing faster rotation to maintain
the same artificial gravity level. The report proposed
joining the aft end of the crew vehicle to the end of a
service vehicle during return to Earth, after the M-3
engine system was cast off, in order to place the cen-
ter of rotation at the joint between the two vehicles
and permit an acceptable rotation rate.
The General Dynamics crew ship design included the
Life Support Section (LSS) for the eight-person crew.
The LSS, which would be tested attached to an Earth-
orbital space station beginning in November 1968,
again illustrated the intense modularity of the
General Dynamics design. The 10-foot-diameter cen-
tral section would be attached to the front of the spine
module and would house the repair shop, food storage,
and radiation-shielded Command Module (not to be
confused with the Apollo CM). The Command Module
would serve double duty as the shipâs radiation shelter
and âlast redoubtâ if all other habitable modules were
destroyed.
Crewmembers would sleep in the
Command Moduleâs lower level to reduce their overall
radiation exposure. The top level would serve as the
crew shipâs bridge and the âblockhouseâ from which the
service vehicles would be remote-controlled.
Two-level, 10-foot-diameter Mission Modules would
cluster around the central section to provide additional
living space. Individual levels could be sealed off if pen-
etrated by meteoroids, and entire Mission Modules
could be cast off if the crew had to reduce spacecraft
mass to permit return to Earthâfor example, if a large
amount of propellant were lost and could not be
replaced from the service vehicles. The LSS would also
include the Earth Entry Module, an Apollo CM-style
conical capsule. In addition to carrying the astronauts
through Earthâs atmosphere at voyageâs end, it would
serve as emergency abort vehicle during the M-1
maneuver. The service vehicles would each carry a
spare Earth Entry Module.
On the service ships, a hangar for robot probes would
replace the LSS.
Unlike the Lockheed and
Aeronutronic reports, the General Dynamics report
treated its automated Mars probes in some detail.
They would include the Returner Mars sample collec-
tor, a Mars Lander based on technology developed for
NASAâs planned Surveyor lunar soft-landing probes,
Deimos Probe (Deipro) and Phobos Probe (Phopro)
Mars moon hard landers based on technology devel-
oped for NASAâs Ranger lunar probes, the Mars
Environmental Satellite (Marens) orbiter, and
Floater balloons.
13
General Dynamicsâ EMPIRE statement of work
specified that it should study piloted Mars-orbital
missions; however, enthusiastic Ehricke could not
resist inserting an option to carry a small piloted
Mars lander. A piloted Mars orbiter must, after all,
enter and depart Mars orbit, thus performing all the
major maneuvers required of a Mars Orbit
Rendezvous landing mission except the landing itself.
The Mars Excursion Vehicle lander, which would be
14
Monographs in Aerospace History
Chapter 3: EMPIRE and After
based on the automated Returner, would be carried in
a service vehicle probe hangar. It would support two
people for seven days on Mars.
14
Ehrickeâs team pro-
posed that a crew test it on the Moon in November
1972.
To get its ships into Earth orbit, Ehrickeâs team
invoked a very large post-Saturn heavy-lift rocket
capable of launching 500 tons. Two of these giants
would be able to place parts for one ship into orbit so that
only one rendezvous and docking would be required to
complete assembly. By contrast, if the Saturn C-5 were
used, eight launches and seven rendezvous and docking
maneuvers would be needed to launch and assemble
each General Dynamics Mars ship. The Ehricke team
targeted post-Saturn vehicle development to commence
in July 1965; the giant rocket would be declared opera-
tional in August 1973.
Mars in Texas
NASAâs Manned Spacecraft Center (MSC) (renamed
the Johnson Space Center in 1973) began as the Space
Task Group (STG) at NASA Langley Research Center
in Hampton, Virginia, where it was formed in late
1958 to develop and manage Project Mercury.
Following Kennedyâs May 1961 Moon speech, the
STGâs responsibilities expanded, so it needed a new
home. The STG became the MSC and moved to
Houston, Texas.
Maxime Faget became MSCâs Assistant Director for
Research and Development. He launched the first MSC
piloted Mars mission study in mid-1961, but it
remained in-house and at a minimal level of effort until
late 1962, after Marshall kicked off EMPIRE. MSCâs
study was supervised by David Hammock, Chief of
MSCâs Spacecraft Technology Division, and Bruce
Jackson, one of his branch chiefs. Chief products of
MSCâs study were a Mars mission profile unlike any
proposed up to that time and the first detailed Mars
Excursion Module (MEM) piloted Mars lander design.
Jackson and Hammock presented MSCâs Mars plan at
the first NASA intercenter meeting focused on inter-
planetary travel, the Manned Planetary Mission
Technology Conference held at Lewis from 21 to 23
May 1963. The NASA Headquarters Office of Applied
Research and Technology organized the meeting,
which focused mainly on specific technologies, many
with applications to missions other than Mars. The
âMission Examplesâ session, chaired by Harry Ruppe,
was relegated to the afternoon session on the last day
of the meeting.
Hammock and Jackson presented MSCâs mission
design publicly for the first time at the American
Astronautical Society (AAS) Symposium on the
Manned Exploration of Mars in Denver, Colorado, the
first non-NASA conference devoted to piloted Mars
travel.
15
George Morgenthaler of Martin Marietta
Corporation in Denver organized the symposium. As
many as 800 engineers and scientists heard 26 papers
and a banquet address by Secretary of the Air Force
Eugene Zuckert. It was the first time so many individ-
uals from Mars-related disciplines came together in
one place, and the last Mars conference as large until
the 1980s. Sky & Telescope magazine reported that the
âDenver symposium . . . helped narrow the gaps
between engineer, biologist, and astronomer.â
16
Hammock and Jackson called Mars âperhaps the
most exciting target for space exploration following
Apollo . . . because of the possibility of life on its sur-
face and the ease with which men might be sup-
ported there.â
17
Two of their plans used variations on
the MOR mode, but the third, dubbed the Flyby-
Rendezvous mode, was novelâit would accomplish a
piloted Mars landing while still accruing the
weight-minimization benefits of a Crocco-type flyby.
The Flyby-Rendezvous mode would use two separate
spacecraft, designated Direct and Flyby. They would
reach Earth orbit atop Saturn V rockets. The unpiloted
Flyby craft would depart Earth orbit 50 to 100 days
ahead of the piloted Direct craft on a 200-day trip to
Mars. The Direct craft, which would include the MEM
lander, would reach Mars ahead of the Flyby craft after
a 120-day flight. The astronauts would then board the
MEM and abandon the Direct craft. The MEM would
land while the Direct craft flew past Mars into solar
orbit. Forty days later the Flyby craft would pass Mars
and begin the voyage back to Earth. The crew would lift
off in the MEM ascent vehicle and set out in pursuit,
boarding the Flyby craft about two days after leaving
Mars. Near Earth the astronauts would separate from
the Flyby spacecraft in an Earth-return capsule, enter
Earthâs atmosphere, and land.
Chapter 3: EMPIRE and After
15
Humans to Mars: Fifty Years of Mission Planning, 1950â2000
One of MSCâs MOR plans used aerobraking, while the
other relied on propulsive braking. In aerobraking, the
lifting-body-shaped Mars spacecraft would skim
through Marsâ upper atmosphere to use drag to slow
down and enter orbit. The Mars surface explorers
would separate from the orbiting ship in the MEM and
land for a surface stay of 10 to 40 days. They would
then lift off in the MEM ascent stage, dock with the
orbiting ship, and leave Mars orbit. Earth atmosphere
reentry would occur as in the Flyby-Rendezvous mode.
Hammock and Jacksonâs propulsive-braking MOR
mission resembled the aerodynamic-braking mode
design, except that a chemical or nuclear propulsion
stage would place the ship in Mars orbit.
Hammock and Jackson found that the chemical all-
propulsive spacecraft design would weigh the most
at Earth-orbit departure (1,250 tons), while the
nuclear aerobraking design would weigh the least
(300 tons). The Flyby-Rendezvous chemical and aer-
obraking chemical designs would weigh about the
same (1,000 tons).
The MEM design for the Houston Centerâs MOR
plansâthe first detailed design for a piloted Mars
landerâwas presented in June 1964 at the next
major meeting devoted to Mars exploration, the
Symposium on Manned Planetary Missions at
Marshall.
18
Philco (formerly Ford) Aeronutronic per-
formed the study between May and December 1963.
Franklin Dixon, the presenter, was Aeronutronicâs
manager for Advanced Space Systems. The design,
which the company believed could land on Mars in
1975, was first described publicly in Houston in
November 1964 at the American Institute of
Astronautics and Aeronautics (AIAA) 3rd Manned
Space Flight Conference.
16
Monographs in Aerospace History
Chapter 3: EMPIRE and After
Figure 1âLanding on Mars. Aeronutronicâs Mars lander, a lifting body glider, relied on aerodynamic lift to minimize required
propellant. The design was based on optimistic estimates of Martian atmospheric density. (âSummary Presentation: Study of
a Manned Mars Excursion Module,â Franklin Dixon, Proceeding of the Symposium on Manned Planetary Missions:
1963/1964 Status, NASA TM X-53049, Future Projects Office, NASA George C. Marshall Spaceflight Center, Huntsville,
Alabama, June 12, 1964, p. 467.)
Dixon pointed out that the chief problem facing Mars
lander designers was the lack of reliable Mars atmos-
phere data, noting that âtwo orders of magnitude vari-
ations in density at a given altitude were possible
when comparing Mars atmosphere models of respon-
sible investigators.â Aeronutronic settled on a
Martian atmosphere comprising 94 percent nitrogen,
2 percent carbon dioxide, 4 percent argon, and traces
of oxygen and water vapor, with a surface pressure of
85 millibars (about 10 percent of Earth sea-level pres-
sure). For operation in this atmosphere, Aeronutronic
proposed a âmodified half-coneâ lifting body with two
stubby winglets. The Aeronutronic MEM would meas-
ure about 30 feet long and 33 feet wide across its tail.
The 30-ton MEM would ride to Mars on its mother-
shipâs back under a thermal/meteoroid shield which
the crew would eject two hours before the Mars
landing. The three-person landing party, which
would consist of the captain/scientific aide, first offi-
cer/geologist, and second officer/biologist, would don
space suits and enter the small flight cabin in the
MEMâs nose. Five minutes before planned deorbit,
the MEM would separate from its mothership and
retreat to a distance of 1,000 feet. There it would
point its tail forward and fire its single descent
engine to begin the fall toward Marsâ surface.
The MEMâs heat-resistant hull would be made
largely from columbium, with nickel-alloy aft sur-
faces. Aeronutronic calculated that friction heating
would drive nose temperature to 3,050 degrees
Fahrenheit. At Mach 1.5, between 75,000 and
100,000 feet above Mars, a single parachute would
be deployed and the MEM would assume a tail-down
attitude. The engine would then ignite a second time
and the parachute would separate. Aeronutronicâs
design included enough propellant for an estimated
60 seconds of hover before touchdown on four land-
ing legs with crushable pads.
Aeronutronic attempted to select a MEM landing site
using photographs taken by Earth-based telescopes.
Theorizing that living things might follow the retreat-
ing edge of the melting polar cap in springtime, they
suggested that NASA target the MEM to Cecropia at
65 degrees north latitude (this corresponds to Vastitas
Borealis north of Antoniadi crater on modern Mars
maps).
19
Upon landing, the astronauts would eject
shields covering the MEM windows and look out over
their landing site to evaluate âlocal hazards,â including
any âunfriendly life forms.â
20
Mars surface access would
be through a cylindrical airlock that lowered like an
elevator from the MEMâs tail.
Dixon stated that âbiological evaluation of life forms is
essential for the first purely scientific effort to allow
pre-contamination studies before man alters the Mars
environment,â
21
implying that little effort would be
made to prevent the astronauts from introducing ter-
restrial microorganisms. Aeronutronic listed âinvesti-
gate life forms for possible nutritional valueâ
22
among
the tasks of the Mars biology study program. The crew
would explore Mars for between 10 and 40 days, spend-
ing about 16 man-hours outside the MEM each day.
Aeronutronicâs MEM was envisioned as a two-stage
vehicle. For return to Mars orbit, the ascent motor
would fire, blasting the flight cabin free of the descent
stage. Two propellant tanks would be cast off during
ascent. After docking with the orbiting mothership, the
MEM flight cabin would be discarded.
Chapter 3: EMPIRE and After
17
Humans to Mars: Fifty Years of Mission Planning, 1950â2000
Figure 2âAstronauts exploring Mars near Aeronutronicâs
lander would take pains to collect biological specimens before
terrestrial contamination made study impossible. A large
dish antenna (left) would let them share their discoveries
with Earth. (âSummary Presentation: Study of a Manned
Mars Excursion Module,â Franklin Dixon, Proceeding of the
Symposium on Manned Planetary Missions:
1963/1964
Status, NASA TM X-53049, Future Projects Office, NASA
George C. Marshall Spaceflight Center, Huntsville,
Alabama, June 12, 1964, p. 470.)
UMPIRE
Every 26 months, an opportunity occurs for a short (six-
month) minimum-energy transfer from Earth to Mars.
In some opportunities the planet is farther from Earth
than in others. This means that in some opportunities
the minimum energy necessary to reach Mars is
greater than in others. The most difficult Mars oppor-
tunities require about 60 percent more energy than the
best opportunities. The more energy required to reach
Mars, the more propellant a spacecraft must expend.
Because of this, a spacecraft launched in a poor Mars
opportunity will weigh more than twice as much as one
launched in a good Mars opportunity.
The quality of Mars launch opportunities runs
through a continuous cycle lasting about 15 years. Not
surprisingly, this corresponds to the cycle of astronom-
ically favorable oppositions described in Chapter 1.
The EMPIRE studies showed that the best Mars
opportunities since 1956 would occur in 1969 and
1971, just as the Apollo lunar goal was reached.
Opportunities would become steadily worse after that,
hitting a peak in 1975 and 1977, then would gradual-
ly improve. The next set of favorable oppositions would
occur in 1984, 1986, and 1988.
The Marshall Future Projects Office contracted with
General Dynamics/Fort Worth and Douglas Aircraft
Company in June 1963 to âsurvey all the attractive
mission profiles for manned Mars missions during the
1975-1985 time period, and to select the mission pro-
files of primary interest.â The study, nicknamed
âUMPIREâ (âUâ stood for âunfavorableâ), was summed
up in a Future Projects Office internal report in
September 1964.
23
General Dynamics and Douglas worked independently,
but each found that the âbest method of alleviating the
cyclic variation of weight required in Earth orbit is to
18
Monographs in Aerospace History
Chapter 3: EMPIRE and After
Figure 3âReturning to Mars orbit: Like the Apollo Lunar Module, Aeronutronicâs lander design used its descent stage as a
launch pad for its ascent stage. Unlike the Lunar Module, it cast off spent propellant tanks as it climbed to orbit. (âSummary
Presentation: Study of a Manned Mars Excursion Module,â Franklin Dixon, Proceeding of the Symposium on Manned
Planetary Missions: 1963/1964 Status, NASA TM X-53049, Future Projects Office, NASA George C. Marshall Spaceflight
Center, Huntsville, Alabama, June 12, 1964, p. 468.)
plan long (900-1100 days) missions.â
24
The companies
advised that âserious consideration . . . be given to the
concept of the first manned landing on Mars being a
long term baseâ rather than a short visit.
25
That is, the
two companies recommended making the first Mars
expedition conjunction class, not opposition class.
The terms âconjunction classâ and âopposition classâ
refer to the position of Mars relative to Earth during
the Mars expedition. In the former, Mars moves behind
the Sun as seen from Earth (that is, it reaches conjunc-
tion) halfway through the expedition; in the latter,
Mars is opposite the Sun in Earthâs skies (that is, at
opposition) at the expeditionâs halfway point.
Conjunction-class expeditions are typified by low-
energy transfers to and from Mars, each lasting about
six months, and by long stays at Marsâroughly 500
days. Total expedition duration thus totals about
1,000 days. The long stay gives Mars and Earth time
to reach relative positions that make a minimum-
energy transfer from Mars to Earth possible. Von
Braun opted for a conjunction-class expedition in The
Mars Project.
Opposition-class Mars expeditions have one low-energy
transfer and one high-energy transfer separated by a
short stay at Marsâtypically less than 30 days. Total
duration is about 600 days. This was the approach
Lewis used in its 1959-1961 study. In the 1960s, most
Mars expedition plans were opposition class.
Because they require more energy, opposition-class
expeditions demand more propellant. All else being
equal, a purely propulsive opposition-class Mars expe-
dition can need more than 10 times as much propellant
as a purely propulsive conjunction-class expedition.
This adds up, of course, to a correspondingly greater
spacecraft weight at Earth-orbit departure.
Therefore, the conjunction-class plan is attractive.
However, the long mission duration is problematical,
for it demands great endurance and reliability from
both machines and astronauts, exposes any crew left in
Mars orbit to risk from meteoroids and radiation for a
longer period, and requires complex Mars surface and
orbital science programs to enable productive use of the
500-day Mars stay.
Mars in California
NASAâs Ames Research Center, a former NACA labora-
tory in Mountainview, California, also became involved
in piloted Mars planning in the EMPIRE era. In 1963,
Ames contracted with the TRW Space Technology
Laboratory to perform a non-nuclear Mars landing expe-
dition study emphasizing weight reduction. Robert Sohn
19
Humans to Mars: Fifty Years of Mission Planning, 1950â2000
Chapter 3: EMPIRE and After
Figure 4âConjunction-class Mars missions include a
low-energy transfer from Earth to Mars, a long stay at
Mars, and a low-energy transfer from Mars to Earth. 1 -
Earth departure. 2- Mars arrival. 3 - Mars departure. 4 -
Earth arrival. (Manned Exploration Requirements and
Considerations, Advanced Studies Office, Engineering and
Development Directorate, NASA Manned Spacecraft Center,
Houston, Texas, February 1971, p. 1-7.)
Figure 5âOpposition-class Mars missions offer a short Mars
stay but require one high-energy transfer, so they demand more
propellant than conjunction-class missions. 1 - Earth depar-
ture (low-energy transfer). 2 - Mars arrival. 3 - Mars departure
(high-energy transfer). 4 - Earth arrival. (Manned Exploration
Requirements and Considerations, Advanced Studies Office,
Engineering and Development Directorate, NASA Manned
Spacecraft Center, Houston, Texas, February 1971, p. 1-8.)
supervised the study for TRW and presented the studyâs
results at the 1964 Huntsville meeting.
26
Sohnâs team
targeted 1975 for the first piloted Mars landing.
TRW found that the biggest potential weight-saver was
aerobraking. For its aerobraking calculations, it used
the Rand Corporationâs August 1962 âConjectural
Model III Mars Atmosphereâ model, which posited a
Martian atmosphere consisting of 98.1 percent nitro-
gen and 1.9 percent carbon dioxide at 10 percent of
Earth sea-level pressure. This atmospheric density and
composition dictated the spacecraftâs proposed shapeâ
a conical nose with dome-shaped tip, cylindrical center
section, and skirt-shaped aft section. This shape was
based on an Atlas missile nose cone. The TRW teamâs
two-stage, 12.5-ton MEM would also use the nose-cone
shape. All else being equal, a version of TRWâs space-
craft for the 1975 Mars launch opportunity that used
braking rockets at Mars and Earth would weigh 3,575
tons, while the companyâs aerobraking design would
weigh only 715 tons.
TRWâs Earth aerobraking system was the Earth
Return Module, a slender half-cone lifting body carried
inside the main spacecraft. A few days before Earth
encounter the crew would enter the Earth Return
Module and separate from the main spacecraft. The
Earth Return Module would enter Earthâs atmosphere
as the main spacecraft flew past Earth into solar orbit.
The TRW study proposed a lightweight artificial grav-
ity systemâa 500-foot tether linking the main space-
craft to the expended booster stage that pushed it from
Earth orbitâwhich would, it calculated, add less than
1 percent to overall spacecraft weight. The resultant
assemblage would spin end over end to produce artifi-
cial gravity. TRW reported that NASA Langley had
used computer modeling to confirm this designâs long-
term rotational stability.
27
TRW found that Earth-Mars trajectories designed to
reduce spacecraft weight at Earth departure would
result in high reentry speeds at Earth return. For
example, an Earth Return Module would reenter at
66,500 feet per second at the end of a 1975 Mars voy-
age, while one returning after a 1980 mission would
reenter at almost 70,000 feet per second. TRW found
that available models for predicting atmospheric fric-
tion temperatures broke down at such speeds.
28
For
comparison, maximum Apollo lunar-return speed was
âonlyâ 35,000 feet per second.
Reentry speed could be reduced by using rockets. TRW
found, however, that including enough propellant to
slow the entire spacecraft from 66,500 feet per second
to 60,000 feet per second would boost spacecraft weight
from 715 tons to 885 tons. Slowing only the Earth
Return Module by the same amount would increase
overall spacecraft weight to 805 tons.
The study proposed a new alternativeâa Venus swing-
by at the cost of a modest increase in trip time. A ship
returning from Mars in 1975 could, the study found, cut
its Earth reentry speed to 46,000 feet per second by
passing 3,300 kilometers over Venusâs night side. A
Venus swingby during flight to Mars in 1973 would
allow the ship to gain speed without using propellant
and thus arrive at Mars in time to take advantage of a
slower Mars-Earth return trajectory. According to
TRWâs calculations, Venus swingby opportunities
occurred at every Mars launch opportunity.
29
20
Monographs in Aerospace History
Chapter 3: EMPIRE and After
Figure 6âTRWâs 1964 Mars ship design, shaped like a
missile warhead, sought to minimize required propellant
by aerobraking in the Martian atmosphere. This cutaway
shows the Mars lander and Earth Return Module inside
the spacecraft. (âSummary of Manned Mars Mission
Study,â Robert Sohn, Proceeding of the Symposium on
Manned Planetary Missions:
1963/1964 Status, NASA
TM X-53049, Future Projects Office, NASA George C.
Marshall Spaceflight Center, Huntsville, Alabama, June
12, 1964, p. 150.)
Building on Apollo
By the end of the June 1964 Marshall Mars sympo-
sium, early flyby detractor Maxime Faget had come
to see some merit in the concept. In a panel discus-
sion chaired by Heinz Koelle, Faget declared that
âwe should, I think, consider a flyby . . . if we under-
take a flyby we really have to face the problems of
man flying out to interplanetary distances . . . . I
think we have to undertake a program that will force
the technology, otherwise we will not get [to Mars] in
my lifetime . . . .â
30
Von Braun, also a panel member, added, that âI think
[piloted] flyby missions, particularly flybys involving
[automated] landing probes . . . would be invaluable
. . . . One such flight, giving us more information on
what to expect . . . on the surface of Mars, will be
extremely valuable in helping us in laying out the
equipment for the landing . . . that would follow the
first flyby flight.â
31
Von Braun then implicitly announced an impending
shift in NASA advanced planning. âI am also inclined to
believe,â he said, âthat our first manned planetary flyby
missions should be based on the Saturn V as the basic
Earth-to-orbit carrier. The reason is that, once the pro-
duction of this vehicle is established and a certain reli-
ability record has been built up, this will be a vehicle
that will be rather easy to get.â Von Braunâs statement
acknowledged that a post-Saturn rocket appeared
increasingly unlikely.
32
In an outline of future plans
submitted to President Lyndon Johnsonâs Budget
Bureau in late November 1964, NASA stated that the
post-Saturn rocket should receive low funding priority,
and called for post-Apollo piloted spaceflight to be
focused on Earth-orbital operations using technology
developed for the Apollo lunar landing.
33
The 1964 decision to use Apollo technology for missions
after the lunar landing could be seen as a rejection of
post-Apollo piloted Mars missions. Historian Edward
Ezell wrote in 1979 that the âdeterminism to utilize
Apollo equipment for the near future was very destruc-
tive to the dreams of those who wanted to send men to
Mars.â
34
As if to emphasize this, the amount of funding
applied to piloted planetary mission studies took a nose
dive after November 1964. In the 17 months preceding
November 1964, $3.5 million was spent on 29 piloted
planetary mission studies. Between November 1964
and May 1966, NASA contracted for only four such
studies at a cost of $465,000.
35
Mars planners were not so easily discouraged, however.
After EMPIRE, and concurrent with UMPIRE, a
Marshall Future Projects Office team led by Ruppe com-
menced an in-house study to look at using Apollo hard-
ware for Mars exploration. Ruppeâs study report, pub-
lished in February 1965, found that piloted Mars flyby
missions would be technically feasible in the mid- to late-
1970s using Saturn rockets and other Apollo hardware.
36
The reportâs flyby spacecraft design used hardware
already available or in an advanced state of development.
Two RL-10 engines would provide rendezvous and dock-
ing propulsion, for example, and an Apollo Lunar Module
descent engine would perform course corrections.
A pressurized hangar would protect a modified Apollo
CSM during the interplanetary voyage. The hangar
would also provide a shirt-sleeve environment so that
the astronauts could act as in-flight caretakers for
five tons of automated probes, including âlanders,
atmospheric floaters, skippers, orbiters, and possibly
probes . . . to perform aerodynamic entry tests [of]
designs and materials.â
37
The last of these would,
Ruppe wrote, provide data to help engineers design
the piloted Mars landers to follow. His report drew on
the UMPIRE conclusions when it stated that
significant reduction of initial mass in Earth
orbit is possible if we can use aerodynamic
braking at Mars or refueling there, but these
methods assume a knowledge about . . . the
Martian atmosphere, or about Mars surface
resources which just is not available. The first
venture, still assuming that we are not very
knowledgeable . . . would probably transport 2
or 3 men to the surface of Mars for a few days
. . . [at a cost of] a billion dollars per man-day
on Mars. If the physical properties of Mars
were well known, we could think . . . of the first
landing as a long-duration base, reducing cost
to less than 10 million dollars per man-day.
38
The three-person flyby crew would live in a spherical
habitat containing a radiation shelter and a small cen-
trifuge for maintaining crew health (the study rejected
artificial gravity systems that rotated the entire craft as
being too complex and heavy). Twin radioisotope power
units on extendible booms would provide electricity.
Chapter 3: EMPIRE and After
21
Humans to Mars: Fifty Years of Mission Planning, 1950â2000
The mission would require six Saturn V launches and
one Saturn IB launch. Saturn V rocket 1 would launch
the unpiloted flyby spacecraft; then Saturn V rockets 2
through 5 would launch liquid oxygen tankers. The
sixth Saturn V would then launch the Earth-departure
booster, a modified Saturn V second stage called the S-
IIB, which would reach orbit with a full load of 80 tons
of liquid hydrogen but with an empty liquid oxygen
tank. Ruppe wrote that solar heating would cause the
liquid hydrogen to turn to gas and escape; to ensure
that enough remained to boost the flyby craft toward
Mars, the S-IIB would have to be used within 72 hours
of launch from Earth.
The three astronauts would launch in the modified
Apollo CSM on the Saturn IB rocket and then board
the flyby spacecraft. They would use the RL-10
engines to guide the flyby craft to a docking with the
S-IIB. The oxygen tankers would then dock in turn and
pump their cargoes into the S-IIBâs empty oxygen
tank. Ruppeâs flyby craft and booster would weigh 115
tons at Earth-orbit departure. The S-IIB would then
ignite, burn to depletion, and detach, placing the flyby
craft on course for Mars.
During the flight, the astronauts would regularly
inspect and service the automated probes. As they
approached Mars, the astronauts would release the
probes and observe the planet using 1,000 pounds of
scientific equipment. The flyby spacecraft would relay
radio signals at a high data rate between the Mars
probes and Earth until it passed out of range; then
direct communication between Earth and the probes
would commence at a reduced data rate.
As Earth grew large again outside the viewports, the
flyby astronauts would enter the modified Apollo CSM
and abandon the flyby craft. The CSMâs propulsion
system would slow it to Apollo lunar return speed,
then the CM would separate from the SM, reenter, and
land. Depending on the launch opportunity used, total
mission duration would range from 661 to 691 days.
Even as Ruppeâs report was published, the ârobot care-
takerâ justification for piloted Mars flybys was becom-
ing increasingly untenable. On 31 July 1964, the
Ranger 7 Moon probe snapped 4,316 images of one cor-
ner of Mare Nubium before smashing into the lunar
surface as planned. The images showed the Moon to be
sufficiently smooth for Apollo landings, and gave the
credibility of robot explorers a vital boost. As Ruppe
published his report, Mariner 4, launched on 28
November 1964, was making its way toward Mars. Not
long after Ruppe published his report, on 20 February
1965, Ranger 8 returned 7,137 images as it plunged
toward the Sea of Tranquillity. A month later, Ranger 9
returned 5,148 breathtaking images of the complex
112-kilometer crater Alphonsus.
Beyond providing engineering and scientific justifica-
tions for the piloted flyby mission, Ruppeâs report ten-
dered a political justification. He wrote:
From the lunar landing in this decade to a
possible planetary landing in the early or
middle 1980s is 10 to 15 years. Without a
major new undertaking, public support will
decline. But by planning a manned planetary
[flyby] mission in this period . . . the United
States will stay in the game.
39
That Ruppe felt it necessary in early 1965 to attempt to
justify a piloted Mars flyby mission in terms of proba-
ble impact on the U.S. domestic political environment is
telling, as will be seen in the next chapter.
22
Monographs in Aerospace History
Chapter 3: EMPIRE and After
An era ended for the National Aeronautics and
Space Administration last week when Congress
voted a $234-million cut in that agencyâs budget
authorization for Fiscal 1968 . . . . The NASA
budget cut is symptomatic of the many currents
of basic change that are flowing through the land
this summer . . . . If top NASA officials have not
interpreted their admittedly long and arduous
buffeting on Capitol Hill this spring and summer
correctly, then they are facing a much worse time
in the years ahead . . . . (Robert Hotz, 1967)
1
Mariner 4
On 15 July 1965, the Mariner 4 probe snapped 21 blur-
ry pictures of Marsâ southern hemisphere as it flew by
at a distance of 9,600 kilometers. The flyby, which
marked the culmination of a seven-and-a-half-month
voyage, was an unprecedented engineering achieve-
ment. Mariner 4 had withstood the interplanetary
environment for nearly twice as long as Mariner 2 had
during its 1962 Venus flyby mission.
Mariner 4 revealed Mars to be a disappointingly
Moonlike, cratered world with no obvious signs of
water. Scientists had expected to see a world more like
Earth, where erosion makes obvious craters the excep-
tion rather than the rule. That Mariner 4âs images were
black and white accentuated the resemblance to
Earthâs desolate satellite. Canals were conspicuously
absent. They are now believed to have been an optical
illusion or a product of eyestrain.
Mariner 4âs impact on Mars exploration planning is
hard to overestimate. First, it showed that Maxime
Faget had been right in 1962. Robots could perform
Mars flybysâastronauts were not required for this
particular exploration mission. It also showed that
robot probes could reach Mars in reasonably good con-
dition, undermining the ârobot caretakerâ justification
for piloted Mars flybys.
Mariner 4âs radio-occultation experiment revealed
Marsâ atmosphere to be less than 1 percent as dense as
Earthâs. Based on these new data and on measure-
ments of the Martian atmosphere made from Earth
since the 1940s, planetary scientists calculated that the
majority of Marsâ atmosphere was carbon dioxide, not
nitrogen, as had been widely supposed.
2
The new Mars atmosphere data relegated to the recycle
bin aerodynamic landing systems such as von Braunâs
delta-winged gliders and Aeronutronicâs lifting-body.
That meant more rocket propulsion would be required
to accomplish a Mars soft landing, which would in turn
demand more propellant. This would boost minimum
lander weight, which meant more propellant would be
needed to transport the lander from Earth to Mars.
This in turn would boost Mars spacecraft weight at
Earth-orbit departure, which meant, of course, that
more expensive rockets would be required to launch
the Mars ship into Earth orbit.
Most importantly, Mariner 4 dealt a body blow to
hopes for advanced Martian life. Historically,
human perceptions of life on Mars have occurred
along a continuum. At one end stood the romantic
view of nineteenth-century American astronomer
Percival Lowell, whose Mars was a dying Earth
inhabited by a race of civil engineers who had dug a
planet-girdling network of irrigation canals to stave
off the encroaching red desert. By the 1930s,
Lowellâs vision was widely seen as optimistic.
Nonetheless, the romance of Lowellâs Mars inspired
would-be Mars explorers into the 1960s.
3
The Mariner 4 results eradicated any lingering
traces of Lowellian romance, and in fact shifted the
prevailing view of life on Mars all the way down the
continuum to a pessimism with almost as little
basis as Lowellâs optimism. The spacecraft had,
after all, imaged only 1 percent of Mars at resolu-
tion so low that, had it photographed Earth, scien-
tists examining its pictures would likely have
missed all signs of terrestrial life.
4
NASA took pains
to point out that Mariner 4 had been intended only
as a first, preliminary step toward resolving the
question of life on Mars, and that it had âblazed the
way for later spacecraft to land instruments and,
eventually, men on Mars.â
5
On the plus side, Mariner 4 provided the first firm
data on conditions astronauts could expect to
encounter in interplanetary space during the voyage
to Mars. The intrepid robot registered fewer meteoroid
impacts than expected, but also detected a higher-
than-expected level of cosmic radiation and between
12 and 20 solar flares during what was expected to be
a quiet Sun period.
6
23
Humans to Mars: Fifty Years of Mission Planning, 1950â2000
Chapter 4: A Hostile Environment
Vietnam and Watts
President Lyndon Johnson supported the lunar pro-
gram launched by his predecessor, which was not sur-
prising, given that he had played a key role in formu-
lating the Moon goal as Kennedyâs Vice President and
National Space Council chair. Like many others, how-
ever, he was uncertain what NASAâs scope and direc-
tion should be in the years after it put an astronaut on
the Moon. In a letter on 30 January 1964, Johnson
asked NASA Administrator James Webb for a list of
possible future NASA goals.
7
As stated in the last chapter, the outline of agency
plans submitted to Johnsonâs Budget Bureau in
November 1964 emphasized using Apollo hardware in
Earth orbit. An Apollo-based piloted program in the
early 1970s was seen as an interim step to an Earth-
orbiting space station in the mid- to late-1970s.
8
When
the National Academy of Sciences Space Science Board
called instead for an emphasis on planetary explo-
ration, NASA officials insisted that the Earth-orbital
focus was President Johnsonâs preference.
9
This philosophyâthat the United States would be best
served by using Apollo hardware as an interim step to
a future space stationâset the tone for much of NASAâs
post-Apollo planning through the beginning of 1969.
NASAâs program for reapplying Apollo hardware was
the Apollo Applications Program (AAP), an initially
ambitious slate of lunar and Earth-orbital missions
that eventually shrank to become the Skylab program.
As shown in the last chapter, Mars planners in the
Future Projects Office at Marshall sought also to apply
Apollo technology to Mars exploration.
An event on 25 January 1965 also helped set the tone
for NASAâs post-Apollo future. On that date, President
Johnson sent to Congress a $5.26-billion NASA budget
for FY 1966, an increase of only $10 million over the
$5.25-billion FY 1965 budget. This was the smallest
NASA budget increase since the agency was estab-
lished in 1958. NASAâs eventual FY 1966 appropriation
was $5.18 billion, the Agencyâs first budget drop. Most
of the cuts came from AAP and other new starts.
This new frugality in the administration and in
Congress with regards to space reflected growing
unease across the United States. In August 1964, fol-
lowing a naval incident in the Gulf of Tonkin off North
Vietnam, Congress passed the Tonkin Resolution,
which empowered President Johnson to take what
steps he deemed necessary to thwart further com-
munist aggression in Indochina. In February 1965,
Vietcong guerrillas attacked the South Vietnamese mil-
itary base at Pleiku, killing 8 Americans and wounding
126. In response, Johnson ordered the bombing of
North Vietnamâs base at Dong Hoi. On 8 March, the
first U.S. combat troopsâtwo battalions of marinesâ
joined the 23,000 American advisors already in South
Vietnam.
As Mariner 4 approached Mars in July, President
Johnson announced that he would increase the number
of soldiers in South Vietnam from 75,000 to 125,000.
On 4 August, while Mariner 4âs images were trickling
back to Earth, Johnson asked Congress for an ad-
ditional $1.7 billion to support the expanding war.
On 11 August, as Mars planners attempted to reconcile
the thin atmosphere and craters revealed by Mariner 4
with their old plans for Mars, racial violence flared in the
Watts ghetto of Los Angeles, California. Five nights of
anarchy left 34 dead and caused $40 million in damage.
Planetary JAG
Against this backdrop of war, social unrest, and
Mariner 4 results, NASA launched a two-prong assault
on Mars. The first, the Voyager program, aimed at plan-
etary exploration using automated orbiters and lan-
ders. The second was an internal piloted Mars flyby
study involving several NASA centers.
As already indicated, planetary scientists had rejected
the AAP space station emphasis in favor of planetary
exploration, which, they felt, was being neglected in
NASAâs headlong rush to reach the Moon. In its report
Space Research: Directions for the Future, released in
January 1966, the National Academy of Sciences Space
Science Board designated âthe exploration of the near
planets as the most rewarding goal on which to focus
national attention for the 10 to 15 years following
manned lunar landing.â
10
In May 1966, the American
Astronomical Society Symposium âThe Search for
Extraterrestrial Lifeâ re-emphasized the importance of
seeking life on Mars despite the Mariner 4 results.
11
These inputs helped build both Voyager and piloted
flyby mission rationales.
24
Monographs in Aerospace History
Chapter 4: A Hostile Environment
25
Humans to Mars: Fifty Years of Mission Planning, 1950â2000
Voyager, first proposed in 1960 at the Jet Propulsion
Laboratory (JPL) in Pasadena, California, was envi-
sioned as a follow-on program to the Mariner flyby
series. The 1960s Voyager should not be confused with
the twin Voyager flyby probes launched to the outer
planets in 1977 and 1978. In the FY 1967 budget cycle,
NASA had postponed proposing Voyager as a new start
following assurances that it could get off to an aggres-
sive start in FY 1968. The delay was partly a result of
the Mariner 4 findings. New atmosphere data forced a
re-design that drove the programâs estimated cost
beyond $2 billion.
12
Voyager was initially targeted for
first launch in 1971, with a second mission in 1973, and
other missions to follow.
The NASA Headquarters Office of Manned Space
Flight (OMSF) under George E. Mueller, Associate
Administrator for Manned Space Flight, managed
the piloted flyby study. Mueller had taken charge of
the OMSF in September 1963 and had set up the
Advanced Manned Missions Office under Edward
Gray in November 1963 to direct NASAâs piloted
planetary mission planning activities. At a meeting
on 15 April 1965, Mueller had received authority
from NASA Deputy Administrator Robert Seamans
to put together a NASA-wide group to plan piloted
planetary missions. A preliminary meeting of the
group occurred on 23 April 1965. This prepared the
ground for development of the Planetary Joint Action
Group (JAG), which was formally established later in
the year. The Planetary JAG was headed by Gray and
drew members from NASA Headquarters, Marshall,
MSC, and Kennedy Space Center (KSC), as well as
from the Apollo planning contractor, Bellcomm.
13
Initially the Planetary JAGâs focus was on piloted
Mars missions using nuclear rockets. In April 1966,
however, Mueller launched a piloted Mars flyby
study within the Planetary JAG at the request of
Nobel Laureate Charles Townes, chair of the NASA
Science and Technology Advisory Committee.
Townes had asked Mueller in January 1966 to carry
out a study comparing the unpiloted Voyager project
with a piloted flyby with robot probes (what he
called a âmanned Voyagerâ).
14
In the second half of
1966, NASA spent $2.32 million on 12 piloted plan-
Chapter 4: A Hostile Environment
Figure 7âThe 1966 Planetary Joint Action Group study used existing and near-term technology for its piloted Mars flyby
spacecraft design. Note the Earth Entry Module (left) based on the Apollo Command Module. (NASA Photo S-66-11230)
etary mission studies supporting the Planetary
JAG.
15
Later that year, Mueller testified to the House Space
Committee on the benefits of a piloted flyby. He
explained that it afforded
the best opportunity for performing manned
planetary exploration with minimal cost and at
an early date . . . . The attractiveness of this
type of mission . . . stems from the relatively
light burden which it imposes on the propul-
sion system, although the short interval of
direct contact with the target planet detracts
from its desirability. The usefulness of the flyby
mission becomes clearly established when
viewed as an in-situ test-bed for evaluating the
performance of various subsystems such as
navigation, life support, and communications
to be used in later landing missions; [and]
when also viewed as a platform for launching
instrumented probes toward the target planet
during the close passage.
16
On 3 October 1966, the Planetary JAG published its
Phase 1 report, Planetary Exploration Utilizing a
Manned Flight System.
17
The report placed piloted fly-
bys within an evolutionary âintegrated programâ of
new and Apollo-based technology with âbalancedâ use
of humans and robots, the objective of which was
âmaximum return at minimum cost, assuming inten-
sive investigation of the planets is a goal.â By this
time the integrated program concept had been dis-
cussed for more than a year outside NASA.
18
The
Planetary JAGâs integrated program proceeded
through the following steps:
âą Apollo Applications Program (1968-73):
Astronauts would remain aloft in space stations
based on Apollo hardware for progressively
longer periods to collect data on human reac-
tions to weightlessness. Some would live in
Earth orbit for more than a year approximately
the duration of a piloted Mars flyby mission.
âą
Mariner (1969-73) and Voyager (1973): The
Planetary JAG report cast Mariner and
Voyager as lead-ins to piloted expeditions by
stating that data they collected would aid engi-
neers designing piloted flyby hardware. A
Mariner probe would fly by Mars in 1969; in
1971 another Mariner would drop a probe into
Marsâ atmosphere. The first Voyager probe
would land on Mars in 1973 bearing a suite of
life-detection experiments.
âą Piloted Mars/Venus Flybys (1975-80): The first
piloted Mars flyby mission would leave Earth-
orbit in September 1975. Mars flyby launch
opportunities would also occur in October 1977
and November 1979. Multiple flyby missions
were possibleâa Venus/Mars mission could
start in December 1978, and a Venus/Mars/
Venus mission could launch in February 1977.
These would dispense automated probes based
on Mariner and Voyager technology.
âą Piloted Mars Landing and piloted Venus
Capture (orbiter) missions (post-1980) would
see introduction of AEC-NASA nuclear-ther-
mal rockets. The Planetary JAG deemed
nuclear propulsion âessential for a flexible
Mars landing programâ
capable of reaching
Mars in any launch opportunity regardless of
the energy required. (The nuclear rocket pro-
gram is described in more detail in Chapter 5.)
The Planetary JAGâs piloted Mars flyby spacecraft
would reach Earth orbit on an Improved Saturn V
rocket with a modified S-IVB (MS-IVB) third stage.
The MS-IVB would feature stretched tanks to
increase propellant capacity and internal foam insu-
lation to permit a 60-hour wait in Earth orbit before
solar heating caused its liquid hydrogen fuel to turn
to gas and escape.
The four-person flyby crew would ride into Earth orbit
on a two-stage Improved Saturn V in an Apollo CSM
stacked on top of the flyby craft. Upon reaching orbit,
the CSM/flyby craft combination would detach from the
spent Saturn V S-II second stage; then the astronauts
would detach the CSM, turn it around, and dock with a
temporary docking structure on the flyby craftâs for-
ward end.
The Planetary JAGâs flyby spacecraft would consist of
the Mid-Course Propulsion Module with four main
engines; the Earth Entry Module, a modified Apollo
CM for Earth atmosphere reentry at missionâs end;
and the Mission Module, the crewâs living and working
26
Monographs in Aerospace History
Chapter 4: A Hostile Environment
27
Humans to Mars: Fifty Years of Mission Planning, 1950â2000
space. The Earth Entry Module would serve double
duty as a radiation shelter during solar flares. Mid-
Course Propulsion Module propellant tanks would be
clustered around it to provide additional radiation
shielding. The Mission Moduleâs forward level (for ârest
and privacyâ) would be lined with lockers containing
freeze-dried foods; the aft level would contain the flyby
craftâs control console, science equipment, and ward-
room table. The Planetary JAG report proposed that
the Mission Module structure and subsystems, such as
life support, be based on Earth-orbital space station
module designs.
The automated probes would be housed in the
Experiment Module forming the aft end of the flyby
spacecraft, along with a probe deployment manipulator
arm, a biology laboratory, a 40-inch telescope, and an
airlock for spacewalks with an Apollo-type docking
unit. A 19-foot-diameter radio dish antenna for high-
data-rate communications with Earth unfolded from
the back of the Experiment Module, as did a 2,000-
square-foot solar array capable of generating 22 kilo-
watts of electricity at Earth, 8.5 kilowatts at Mars, and
4.5 kilowatts in the Asteroid Belt.
With the crew and flyby craft in Earth orbit, three
Improved Saturn V rockets would launch 12 hours
apart to place the three MS-IVB rocket stages in orbit.
Chapter 4: A Hostile Environment
Figure 9âThree modified Apollo S-IVB stages burn one
after the other to launch the 1967 Planetary Joint Action
Group Mars flyby spacecraft out of Earth orbit. (NASA
Photo S-67-5998)
Figure 8âTypical piloted Mars flyby mission. 1âdepart Earth orbit. 2, 4, 10âcourse corrections. 3, 5, 6, 7âeject automated
Mars probes. 8âautomated probe collects Mars surface sample and launches it off the planet. 9âpiloted flyby craft retrieves
Mars surface sample. 11âcrew leaves Mars flyby craft in Earth return capsule. The abandoned flyby spacecraft sails past
Earth into solar orbit. 12âEarth atmosphere reentry and landing. (Planetary Exploration Utilizing a Manned Flight
System, Office of Manned Space Flight, NASA Headquarters, Washington, DC, October 3, 1966, p. 16.)
28
Monographs in Aerospace History
This rapid launch rate, a veritable salvo of 3,000-ton
rockets, each nearly 400 feet tall, would demand con-
struction of a third Saturn V launch pad at KSC. The
Planetary JAG determined, however, that Pad 39C
would be the only major new ground facility needed to
accomplish its flyby program.
Using the CSMâs propulsion system, the astronauts
would perform a series of rendezvous and docking
maneuvers to bring together the flyby craft and three
MS-IVBs. The flyby crew would then undock the CSM
from the temporary docking structure, re-dock it to the
airlock docking unit on the flyby craftâs side, and enter
the flyby craft for the first time. They would discard the
CSM and eject the temporary docking structure.
Launch from Earth orbit would occur between 5
September and 3 October 1975. The MS-IVB stages
would in turn ignite, deplete their propellants, and be
discarded. As Earth and Moon shrank in the distance,
the crew would deploy the radio antenna and rectan-
gular solar array.
The astronauts would perform a wide range of scien-
tific experiments during the 130-day flight to Mars.
These included solar studies, monitoring themselves to
collect data on the physiological effects of weightless-
ness, planetary and stellar observations, and radio
astronomy far from terrestrial radio interference.
Mars flyby would occur between 23 January and 4
February 1976, the precise date being dependent on the
date of Earth departure. Beginning several weeks before
flyby, the crew would turn the craftâs telescope toward
Mars and its moons. The pace would quicken 10 days
before flyby, when the flyby craft was 2 million kilome-
ters from Mars. At that time the astronauts would use
the probe deployment arm to unstow and release the
automated probes. At closest approach, the flyby space-
craft would fly within 200 kilometers of the Martian
dawn terminator (the line between day and night).
For the 1975 mission, the flyby craft would carry in its
Experiment Module three 100-pound Mars impactors,
one five-ton Mars polar orbiter, one 1,290-pound Mars
lander, and one six-ton Mars Surface Sample Return
(MSSR) lander. The MSSR was designed to leave the
flyby craft, land on Mars, gather a two-pound sample of
dirt and rock, and then blast it back to the passing flyby
craft using a three-stage liquid-fueled ascent vehicle.
This last concept, an effort to improve the piloted flyby
missionâs scientific productivity, was proposed by
Chapter 4: A Hostile Environment
Figure 11âThe 1967 Planetary Joint Action Groupâs Mars
flyby spacecraft releases automated probes and deploys
instruments. Close Mars flyby would last mere hours, but the
astronauts would study themselves throughout the mission,
helping to pave the way for future Mars landing expeditions.
(NASA Photo S-67-5999)
Figure 10âFollowing final S-IVB stage separation, the 1967
Planetary Joint Action Groupâs Mars flyby spacecraft deploys
solar arrays and a dish-shaped radio antenna. (NASA Photo
S-67-5991)
29
Humans to Mars: Fifty Years of Mission Planning, 1950â2000
Bellcomm at the Planetary JAGâs meeting at KSC on
29-30 June 1966.
19
The concept originated in a paper by
R. R. Titus presented in January 1966.
20
Titus, a United
Aircraft Research Laboratories engineer with a talent
for unfortunate acronyms, dubbed his concept FLEM,
for âFlyby-Landing Excursion Mode.â He had been part
of the Lockheed EMPIRE team.
Titusâ mission plan had a piloted MEM lander sep-
arating from the flyby spacecraft during the Mars voy-
age and changing course to intersect the planet. Titus
calculated that MEM separation 60 days before Mars
flyby would permit it to stay for 16 days at Mars, while
separation 30 days out yielded a 9-day stay time. At
Mars the MEM would fire its rocket engine to enter
orbit, then land. As the flyby spacecraft passed Mars,
the excursion module would blast off in pursuit. The
amount of propellant required for FLEM was much
less than for an MOR landing mission because only
the MEM would enter and depart Mars orbit. Titus
calculated that a FLEM mission boosted to Mars in
1971 using a nuclear-thermal rocket might weigh as
little as 130 tonsâlight enough, perhaps, to permit a
piloted Mars landing with a single Saturn V launch.
In the 1966 JAG piloted flyby plan, the automated
MSSR would land on Mars about two hours before the
flyby craft flew past the planet and would immediately
set to work gathering rock and soil samples using
scoop, brush, sticky tape, drill, and suction collection
devices. Less than two hours after MSSR touchdown,
its ascent vehicle first stage would ignite. If all went
well, the ascent vehicleâs small third stage would deliv-
er the samples to a point in space a few miles ahead of
the flyby craft about 17 minutes later, 5 minutes after
the flyby craftâs closest Mars approach. As their craft
overtook the sample package, the astronauts would
snatch it in passing using a boom-mounted docking
ring. They would then deposit it inside the Experiment
Moduleâs biology lab.
The Planetary JAG pointed out that the MSSR/piloted
flyby approach improved the chances for studying liv-
ing Martian organisms because the Mars samples
would reach a trained biologist within minutes of col-
lection. Living organisms collected using a purely auto-
mated sample-return lander would likely perish during
the months-long flight to a lab on Earth.
The trip back to Earth would last 537 days, during
which the astronauts would study the Mars samples
and repeat many of the same experiments per-
formed during the Earth-Mars voyage. The flyby
craft would penetrate the Asteroid Belt before
falling back to Earth, making piloted asteroid flybys
a possibility. When farthest from the Sun the flyby
craft would be on the opposite side of the Sun from
Earth, making possible simultaneous observations
of both solar hemispheres.
A few days before reaching Earth, the crew would
board the Earth Entry Module and abandon the flyby
craft. On 18 July 1977, the Earth Entry Module would
reenter Earthâs atmosphere, deploy parachutes, and
lower to a land touchdown, while the flyby craft would
fly past Earth into solar orbit. Just before the landing,
solid-propellant rocket motors would fire to cushion
impact, ending the 667-day Martian odyssey.
The Fire
NASAâs FY 1967 funding request was $5.6 billion. The
White House Budget Bureau trimmed this to $5.01 bil-
lion out of a $112 billion Federal budget before sending
the budget on to Capitol Hill. By the time President
Johnson signed it into law, NASAâs FY 1967 appropria-
tion was $4.97 billion, more than $200 million less than
FY 1966. Programs aimed at giving NASA a post-
Apollo future were hardest hit. Of the $270 million
NASA requested for AAP, for example, only $83 million
was appropriated. Voyager funding start-up was
bumped to FY 1968. Apollo Moon program funding, by
contrast, barely suffered. In part this was because the
agency was flying frequent Gemini missionsâ10 in 20
monthsâwhich kept the Moon goal in the public eye.
Kennedyâs goal seemed very close, with the first piloted
lunar landing expected in just over a year.
In Geminiâs last year, however, Americaâs attention was
increasingly drawn away from space. In March 1966,
protesters marched against the Vietnam War in
Boston, San Francisco, Chicago, Philadelphia, and
Washington. The summer of 1966 saw race riots in
Chicago and Atlanta and racist mob violence in
Grenada, Mississippi. In June 1966, President Johnson
ordered bombing raids against the North Vietnamese
cities of Haiphong and Hanoi. By then, 285,000
Americans were serving in Vietnam. As Gemini 12, the
Chapter 4: A Hostile Environment
last in the series, splashed down in November 1966, the
number of American soldiers on the ground in Vietnam
was well on its way to its 1 January 1967 total of
380,000.
Against this backdrop, in January 1967, the Planetary
JAG resumed piloted flyby planning, this time with the
purpose of developing âa clear statement of the activi-
ties required in FY 69 for budget discussionsâ
21
to place
NASA âin a position to initiate a flyby project in FY
1969.â
22
Planetary JAG participants had some reason to
be hopeful. As they reconvened, President Johnson
announced a $5.1-billion FY 1968 NASA budget that
included $71.5 million for Voyager and $8 million for
advanced planning. He also backed $455 million for a
substantial AAP. In presenting his budget, the
President explained that âwe have no alternative unless
we wish to abandon the manned space capability we
have created.â
23
On 26 January the OMSF presented its ambitious AAP
plans to Congress. Barely more than a day later,
NASAâs plans received a harsh blow as fire erupted
inside the AS-204 Apollo spacecraft on the launch pad
at KSC, killing Apollo 1 astronauts Gus Grissom, Ed
White, and Roger Chaffee. They had been scheduled to
test the Apollo CSM for 14 days in Earth orbit begin-
ning in mid-February. NASA suspended piloted Apollo
flights pending the outcome of an investigation. The
AS-204 investigation report, issued in April, found
shortcomings in Apollo management, design, construc-
tion, and quality control. Apollo redesign kept
American astronauts grounded until September 1968.
After the fire, NASA could no longer count on a friend-
ly reception on Capitol Hill. The fire, plus growing
pressure on the federal budget, meant that all NASA
programs were subjected to increased oversight. In
March, Aviation Week & Space Technology reported a
âgrowing antipathy from Congressâ toward NASAâs
programs, adding that â[d]elays in the manned pro-
gram, resulting from the Apollo 204 crew loss . . . will
hamper the agencyâs arguments before Congress since
public interest will dwindle without spectacular
results.â
24
The magazine predicted, however, that
Project Geminiâs conclusion would free up funds in FY
1968,
permitting âa modest start on Apollo
Applications and . . . Voyager.â
25
As NASA in general came under increased scrutiny, the
piloted flyby concept suffered high-level criticism for
the first time. The Presidentâs Science Advisory
Committee (PSAC) report The Space Program in the
Post-Apollo Period (February 1967) was generally posi-
tive, calling for continued Apollo missions to the Moon
after the first piloted lunar landing, as well as plane-
tary exploration using robots such as Voyager.
26
The
PSAC reiterated Fagetâs 1962 criticism of the piloted
flyby mission, however, stating that
the manned Mars flyby proposal, among its
other weaknesses, does not appear to utilize
man in a unique role . . . it appears to us that
NASA must address itself more fully to the
question, âWhat is the optimum mix of manned
and unmanned components for planetary
exploration?â
27
The PSAC also complained that Voyager and the
Planetary JAGâs piloted flyby plans were âdistinct and
apparently independent plans for planetary explo-
ration,â and criticized NASA for âabsence of integrat-
ed planning in this area.â
28
As has been seen, this crit-
icism reached the Planetary JAG early enough for an
integrated plan to be included in its report. NASA
officials denied, however, that the PSACâs criticisms
had prompted its effort to integrate Voyager and the
piloted flyby.
29
The PSACâs critique stung the Planetary JAG. One
response was to distance itself from the term âflybyââa
word identified increasingly with automated explorers
since Mariner 4âs successâby dubbing its mission an
âencounter.â
30
Planetary JAG members also sought to
reemphasize that the encounter mission astronauts
would accomplish productive observations and experi-
ments throughout their two-year voyage, not just dur-
ing the hours of Mars encounter.
OMSF advanced planner Edward Gray and his deputy
Franklin Dixon first publicly proposed the Planetary
JAGâs Apollo-based piloted Mars flyby as an FY 1969
new start the next month (March 1967) at the AAS
Fifth Goddard Memorial Symposium, where they pre-
sented a paper called âManned Expeditions to Mars
and Venus.â
31
That same month, NASA forecast a stable
annual budget of about $5 billion per year through
1970, after which the budget would decline to $4.5 bil-
lion annually for the rest of the 1970s. New programs
30
Monographs in Aerospace History
Chapter 4: A Hostile Environment
such as Voyager and the piloted flyby would be phased
in as the share of NASAâs budget allotted to Apollo
lunar missions decreased.
32
In May, Aviation Week &
Space Technology reported that the $71.5-million new-
start funding approved for Voyager by the House Space
Committee âdoes not face serious problems.â
33
A New Era for NASA
By the beginning of 1967, 25,000 United States service-
men had died in Vietnam. The summer of 1967 saw
racial violence wrack Newark, New Jersey, and Detroit,
Michigan. Large sections of Detroit burned to the
ground. At least 5,000 people lost their homes, and
more than 70 lost their lives. Violence also swept more
than 100 other American cities. Detroit alone suffered
up to $400 million in damage. Needless to say, most
Americans focused more on Earth than on space.
The cost of the Vietnam War soared to $25 billion a
yearâthe entire FY 1966 NASA budget every 10
weeks. This, plus the cost of President Johnsonâs Great
Society social welfare programs, led to spiraling
Federal budget deficits. Congress approached the
Johnson Administrationâs 1968 Federal Budget with its
scissors out, and NASA was an easy target.
In early July, Aviation Week & Space Technology
reported that the House and Senate had âsustained
the pace of spending in the Apollo program but seri-
ously cut into NASAâs plans for both manned and
unmanned space programs of the future.â
34
The
Senate voted down all Voyager funding, while the
House cut the program to $50 million. House and
Senate conferees settled on $42 million for the auto-
mated Mars program. In response, NASA announced
that a 1971 Voyager mission was out of the question.
A 1973 landing was, however, still feasible if the pro-
gram was funded adequately in FY 1969.
35
In early July, the Senate report on its FY 1968 NASA
authorization bill specifically advised against piloted
planetary missions, stating that âall near-term [piloted]
missions should be limited to earth orbital activity or
further lunar exploration.â
36
Later that month, in testi-
mony to the Senate Appropriations Committee, James
Webb refused to âgive aid and comfort to those who
would cut our programâ when asked by Spessard
Holland (Democrat-Florida) to choose between $45
million for AAP and $50 million for Voyager. Holland
chided Webb for âfailing to see that Congress is faced
with dilemmas in applying all its economies.â
37
That some in the aerospace world were sympathetic to
Hollandâs plight is telling. In an editorial titled âNew
Era for NASA,â for example, Aviation Week & Space
Technology editor Robert Hotz wrote,
We have no quarrel with reductions imposed so
far by Congress . . . . They reflect a judicious and
necessary pruning of NASAâs budget . . . . [Space
exploration] cannot hope to occupy such a large
share of the national spotlight in the future as
it did during the pioneering days of Mercury
and Gemini when the war in Vietnam was only
a tiny cloud on a distant horizon; when no
American city cores had yet glowed red at night,
and when a tax cut was the order of the day
instead of the tidal wave of tax rises that now
threatens to engulf the nation.
38
Though none of this augured well for piloted planetary
missions, the Planetary JAG continued planning its
piloted encounter mission with the aim of seeing it
included as an FY 1969 new start. The revised
Planetary JAG plan called for just two MS-IVBs.
39
This
meant that only two Saturn V rockets would need to be
launched in rapid succession, so the costly new Pad 39C
was no longer required.
The encounter spacecraft would again include an
Experiment Module with an automated probe suite
based on Voyager technology. This time, however, the
probes, including at least one large MSSR lander,
would be sealed in the Experiment Module before
launch from Earth and sterilized to avoid biological
contamination of Mars. Previous piloted flyby studies
had justified the presence of astronauts in part by their
ability to service the probes during flight. This would
now be impossible because servicing would introduce
contamination.
The Planetary JAG realized that the MSSR was the
most challenging element of its encounter mission
planâthe one demanding the earliest development
start if the first piloted encounter mission was to be
ready for flight in 1975. On 3 August 1967, therefore,
MSC issued a Request for Proposals for a â9-month
engineering study . . . to perform a detailed analysis
31
Humans to Mars: Fifty Years of Mission Planning, 1950â2000
Chapter 4: A Hostile Environment
32
Monographs in Aerospace History
and preliminary design study of unmanned probes that
would be launched from a manned spacecraft on a
Mars encounter or a Mars capture mission, [and] would
retrieve samples of the Mars surface and atmosphere
and rendezvous with the manned spacecraft.â MSC
added, âThe results of this studyâ would âaid in select-
ing experiment payload combinations of these and
other probes and in configuring the Experiment
Module section of the manned spacecraft used in the
Mars . . . Reconnaissance/Retrieval missions in the
1975-1982 time period.â Cost and technical proposals
were to be submitted to MSC by 4 September.
40
At the
same time, MSC released an RFP calling for a piloted
flyby spacecraft design study.
The Planetary JAG knew of the de facto congressional
âno new startsâ injunction but apparently assumed
that it did not apply to studies with implications
beyond the next fiscal year.
41
Congressman Joseph
Karth (Democrat-Minnesota), chair of the House
Subcommittee on Space Science and Applications, saw
it differently. Normally a strong NASA supporter, he
lashed out at the âostrich-like, head-in-the-sand
approach of some NASA planning,â and added, âVery
bluntly, a manned mission to Mars or Venus by 1975 or
1977 is now and always has been out of the questionâ
and anyone who persists in this kind of misallocation of
resources is going to be stopped.â
42
By August, the expected 1967 Federal budget deficit
was $30 billion. Goaded by MSCâs Request for
Proposals, on 16 August 1967 the House zeroed out
funding for both Voyager and advanced piloted mission
planning. AAP funding fell to $122 million. On 22
August, the House approved a $4.59 billion FY 1968
NASA budgetâa cut of more than $500 million from
the January 1967 White House request.
Faced by a spiraling budget deficit, war and anti-war
dissent, and urban riots, President Johnson reduced his
support for NASA, saying, âUnder other circumstances
I would have opposed such a cut. However, conditions
have greatly changed since I submitted my January
budget request.â
43
He added, âSome hard choices must
be made between the necessary and the desirable . . . .
We . . . dare not eliminate the necessary. Our task is to
pare the desirable.â
44
Denouement
The Voyager program died in part because NASA cast
it as a lead-in to piloted flybys. The scientific com-
munity viewed Voyagerâs loss as a slap in the face. In
September, in an unusual move, NASA officials went
before the Senate Appropriations Committee to nego-
tiate a Mariner mission in 1971 and a Mars landing
mission in 1973, both designed âto conform to sharply
reduced funding in FY 1969.â
45
The 1971 Mariner
mission became Mariner 9. In March 1968, NASA
unveiled Project Vikingâa cut-price version of the
Voyager program. Viking, managed by NASAâs
Langley Research Center, emerged as one of the few
FY 1969 NASA new starts.
MSC received and reviewed MSSR study proposals
from industry, although, of course, no contract for such
a study was ever issued. The piloted flyby mission, the
object of so much study from mid-1962 to late 1967,
was defunct. Despite the obvious congressional hos-
tility toward advanced planning, however, NASAâs
piloted Mars mission studies were not. As will be
seen in the next chapter, the focus shifted to the
other area of Planetary JAG emphasisâpiloted
Mars landing missions using nuclear rockets.
Chapter 4: A Hostile Environment
33
Humans to Mars: Fifty Years of Mission Planning, 1950â2000
Thus, Mr. Vice Presidentâ[the s]olar system is
opening up before us. With landing on the
Moon we know that man can lay claim to the
planets for his use. We know further that man
will do this. The question is when? We know
that [the] U.S. will take part. The question is
how soon will we follow up on what we have
begun with Apollo? It could be the early 1980s.
(Thomas Paine, 1969)
1
The Big Shot
In a November 1965 article on the next 20 years of
space flight, Wernher von Braun sought to convey the
Saturn V rocketâs immense potential. âOne Saturn V
alone,â he wrote, âwill carry twice as much payload as
the entire NASA space program up to this point in
time. In fact, all the orbiters, all the deep space
probes, and all the Mercurys and Geminis that have
ever flown would only load the cargo compartment of
one Saturn V to 50% of capacity.â
2
With Saturn V
available, the Moon, Mars, and indeed the entire solar
system seemed within reach.
The first of fifteen Saturn Vâs ordered by NASA to sup-
port Project Apollo rolled out to Launch Pad 39A at
Kennedy Space Center on 26 August 1967. Designated
AS-501, the mighty rocket would launch Apollo 4, the
first unmanned test of an Apollo CSM spacecraft. The
24-hour countdown commenced early on 8 November
and reached T-0 at 7 a.m. Eastern Standard Time on 9
November. Seen from the KSC press site, three and
one-half miles from the pad, the white and black
rocket rose slowly at the summit of an expanding
mountain of red flame and gray smoke. Thunder from
âthe Big Shot,â as the news media nicknamed AS-501,
drowned out television and radio reporters giving live
commentary and threatened to collapse their temporary
studios.
AS-501 stood 111 meters tall and weighed about 2,830
metric tons at liftoff. Its 10-meter-diameter S-IC first
stage carried 2,090 metric tons of kerosene fuel and
liquid oxygen oxidizer for its five F-1 rocket engines.
They gulped 13.6 metric tons of propellants each sec-
ond to develop a total of 3.4 million kilograms of thrust
at liftoff. AS-501âs first stage depleted its propellants in
two and one-half minutes at an altitude of 56 kilome-
ters, detached, and crashed into the Atlantic about 72
kilometers from Pad 39A.
The 10-meter-diameter S-II second stage carried 423
metric tons of liquid hydrogen and liquid oxygen for
its five J-2 engines, which developed a total of 1 mil-
lion pounds of thrust. The S-II depleted its propel-
lants after six and one-half minutes at an altitude of
161 kilometers.
The 6.7-meter-diameter S-IVB third stage carried 105
metric tons of liquid hydrogen and liquid oxygen for its
single restartable J-2 engine, which fired for two min-
utes to place the Apollo 4 CSM in a 185-kilometer park-
ing orbit. For an Apollo lunar mission, the J-2 engine
would ignite again after one orbit to place the Apollo
spacecraft on course for the Moon. For Apollo 4, the
third stage restarted after two Earth orbits, 3 hours and
11 minutes after liftoff, putting the stage and spacecraft
into an Earth-intersecting ellipse with a 17,335-kilome-
ter apogee (highest point above the Earth).
The Apollo 4 CSM separated from the S-IVB stage,
then fired its engine for 16 seconds to nudge its apogee
to 18,204 kilometers. The CSM engine ignited a second
time 8 hours and 10 minutes into the flight to throw
the CM at Earthâs atmosphere at a lunar-return speed
of about 40,000 kilometers per hour. The CM separated
and positioned itself with its bowl-shaped heat shield
forward. Heat shield temperature soared to 2,760
degrees Celsius, and CM deceleration reached eight
times the pull of Earthâs gravity. Three parachutes
opened, and the Apollo 4 CM splashed into the Pacific
Ocean 10 kilometers from the planned spot, 8 hours
and 38 minutes after liftoff.
The success of AS-501/Apollo 4 helped rebuild confi-
dence in NASAâs ability to fulfill Kennedyâs mandate
following the January 1967 fire. President Johnson told
reporters that the âsuccessful completion of todayâs
flight has shown that we can launch and bring back
safely to Earth the space ship that will take men to the
[M]oon.â Von Braun told reporters that he regarded
âthis happy day as one of the three or four highlights of
my professional lifeâto be surpassed only by the
manned lunar landing.â
3
âTo the Very Ends of the Solar Systemâ
Apollo 4 also cheered Mars planners, for Saturn V had
become their launch vehicle of choice following the end
of post-Saturn rocket planning in 1964. NASA and AEC
engineers developing the NERVA nuclear-thermal
Chapter 5: Apogee
rocket engine saw special cause for celebration, for
Saturn V was their brainchildâs ride into space. The
encouragement was well timed. NERVA, which stood
for Nuclear Engine for Rocket Vehicle Application, still
had no approved mission and had just survived a nar-
row scrape in a Congress ill-disposed toward funding
technology for future space missions.
NERVA was a solid-core nuclear-thermal rocket
engine. Hydrogen propellant passed through and was
heated by a uranium nuclear reactor, which caused the
propellant to turn to plasma, expand rapidly, and vent
out of a nozzle, producing thrust. Unlike chemical
rockets, no oxygen was required to burn the hydrogen
in the vacuum of space. Nuclear-thermal rockets
promised greater efficiency than chemical rockets,
meaning less propellant was required to do the same
work as an equivalent chemical system. This would
reduce spacecraft weight at Earth-orbit departure,
opening the door to a broad range of advanced mis-
sions.
Initial theoretical work on nuclear-thermal rockets
began at Los Alamos National Laboratory (LANL) in
1946. The New Mexico laboratory operated under the
aegis of the AEC. The joint AEC-U.S. Air Force ROVER
nuclear rocket program began in 1955, initially to
investigate whether a nuclear rocket could provide
propulsion for a massive intercontinental missile. In
1957, the solid-core reactor engine design was selected
for ground testing. The test series engine was appro-
priately named Kiwi, for it was intended only for
ground testing, not for flight.
Citing LANLâs nuclear rocket work, AEC supporters in
the U.S. Senate, led by New Mexico Democrat Clinton
Anderson, pushed unsuccessfully in 1958 for the com-
mission to be given control of the U.S. space program.
Anderson was a close friend of Senate Majority Leader
Lyndon Johnson, who led the Senate Space Committee
formed after Sputnik 1âs launch on 4 October 1957.
4
In
October 1958, the Air Force transferred its ROVER
responsibilities to the newly created NASA, and
ROVER became a joint AEC-NASA program. AEC and
NASA set up a joint Space Nuclear Propulsion Office
(SNPO). NASA Lewisâwhich at this time was per-
forming the first NASA Mars study, an examination of
the weight-minimizing benefits of advanced propul-
sion, including nuclear rockets (see chapter 2)âbecame
responsible within NASA for technical direction of the
ROVER program.
In July 1959, the first Kiwi-A test was carried out suc-
cessfully using hydrogen gas as propellant at the
Nuclear Rocket Development Station (NRDS) at
Jackass Flats, Nevada, 90 miles from Las Vegas.
Senator Anderson arranged for delegates to the
Democratic National Convention to be on hand for the
second Kiwi-A test in July 1960. At the Convention,
Anderson arranged for a plank on nuclear rocket
development to be inserted into the Democratic Party
platform.
5
In October 1960, the third Kiwi-A test using
hydrogen gas showed promising results, building sup-
port for a contract to be issued for development of a
flight-worthy nuclear rocket engine.
The Democratic ticket of John Kennedy and Lyndon
Johnson narrowly defeated Dwight Eisenhowerâs Vice
President, Richard Nixon, in the November 1960 elec-
tion. Anderson took over as head of the Senate Space
Committee. President Kennedy embraced space after
the Soviet Union helped end his White House honey-
moon by launching the first human into space on 12
April 1961. He charged Johnson with formulating a
visible, dramatic space goal the United States might
reach before the Soviets. Johnson suggested landing
an American on the Moon.
Before a special joint session of Congress on 25 May
1961, Kennedy called for an American astronaut on the
Moon by the end of the 1960s. Then he asked for âan
additional $23 million, together with $7 million already
available, [to] accelerate development of the ROVER
nuclear rocket. This gives promise of some day provid-
ing a means for even more exciting and ambitious
exploration of space, perhaps beyond the Moon, per-
haps to the very ends of the solar system . . . .â
6
Because of Kennedyâs speech, FY 1962 saw the real
start of U.S. nuclear rocket funding. NASA and the
AEC together were authorized to spend $77.8 million
in FY 1962. Funding in the preceding 15 years had
totaled about $155 million.
In July 1961, Aerojet-General Corporation won the con-
tract to develop a 200,000-pound-thrust NERVA flight
engine. NERVA Phase 1 occurred between July 1961
and January 1962, when a preliminary design was
developed and a 22.5-foot NERVA engine mockup was
34
Monographs in Aerospace History
Chapter 5: Apogee
assembled. At the same time, NASA Marshall set up
the Nuclear Vehicle Projects Office to provide technical
direction for the Reactor-In-Flight-Test (RIFT), a
Saturn V-launched NERVA flight demonstration
planned for 1967.
The first Kiwi-B nuclear-thermal engine ground test
using liquid hydrogen (December 1961) ended early
after the engine began to blast sparkling, melting bits
of uranium fuel rods from its reactor core out of its noz-
zle. Though the cause of this alarming failure remained
unknown, Lockheed Missiles and Space Company was
made RIFT contractor in May 1962. In early summer
1962 the Marshall Future Projects Office launched the
EMPIRE study, motivated in part by a desire to de-
velop missions suitable for nuclear propulsion. Hence,
early on NERVA became closely identified with Mars.
The second and third Kiwi-B ground tests (September
1962 and November 1962) failed in the same manner as
the first. Failure cause remained uncertain, but vibra-
tion produced as the liquid hydrogen propellant flowed
through the reactor fuel elements was suspected.
The PSAC and the White House Budget Bureau allied
against the nuclear rocket program following the third
Kiwi-B failure. They opposed funding for an early RIFT
flight test because they saw it as a foot in the door lead-
ing to a costly piloted Mars mission, and because they
believed the technology to be insufficiently developed,
something the Kiwi-B failures seemed to prove.
Kennedy himself intervened in the AEC-NASA/Budget
Bureau-PSAC deadlock, visiting Los Alamos and the
NRDS in December 1962.
On 12 December 1962, Kennedy decided to postpone
RIFT until after additional Kiwi-B ground tests had
occurred, explaining that âthe nuclear rocket . . . would
be useful for further trips to the [M]oon or trips to
Mars. But we have a good many areas competing for
our available space dollars, and we have to channel it
into those programs which will bring a resultâfirst,
our [M]oon landing, and then consider Mars.â
Kennedyâs decision marked the beginning of annual
battles to secure continued nuclear rocket funding.
7
At the May 1963 AAS Mars symposium in Denver,
SNPO director Harold Finger pessimistically reported
that nuclear rockets were not likely to fly until the mid-
1970s.
8
However, the fourth Kiwi-B test, in August
1963, revealed that vibration had indeed produced the
earlier core failures. The problem had a relatively easy
solution, so NASA, AEC, and nuclear engine supporters
in Congress became emboldened. They pressed
Kennedy to reverse his December 1962 decision.
William House, Aerojet-Generalâs Vice President for
Nuclear Rocket Engine Operations, felt sufficiently
optimistic in October 1963 to tell the British
Interplanetary Societyâs Symposium on Advanced
Propulsion Systems that a Saturn V would launch a 33-
foot-diameter RIFT test vehicle to orbit in 1967. He
predicted that one NERVA stage would eventually be
able to inject 15 tons on direct course to Mars, or 3 tons
on a three-year flight to distant Pluto.
9
Kennedy never had the opportunity to reconsider his
RIFT decision. Following the young Presidentâs
November 1963 assassination, President Johnson
took up the question. With an eye to containing gov-
ernment expenditures, he canceled RIFT in December
1963 and made NERVA a ground-based research and
technology effort.
The year 1964 saw the successful first ground test of
the redesigned Kiwi-B engine and the first NERVA
start-up tests. It also marked the nuclear rocket pro-
gramâs peak funding year, with a joint AEC-NASA
budget of $181.1 million. Though NERVA was ground-
ed, work proceeded under the assumption that success
would eventually lead to clearance for flight.
The nuclear rocket program budget gradually declined,
dropping to $140.3 million in FY 1967. NERVA did not
come under concerted attack, however, until the bitter
battle over the FY 1968 NASA budget. In August 1967,
Congress deleted all advanced planning and Mars
Voyager funds from NASAâs FY 1968 budget because it
saw them as lead-ins to a costly piloted Mars program,
and Johnson refused to save them (see chapter 4).
NERVA funding was eliminated at the same time.
Voyager had to wait until FY 1969 to be resurrected
as Viking. Through Andersonâs influence, however,
NERVA did betterâthe nuclear rocket program was
restored with a combined AEC-NASA budget of
$127.2 million for FY 1968. As if to celebrate
Andersonâs intervention, the NRX-A6 ground test in
December 1967 saw a NERVA engine operate for 60
minutes without a hitch.
35
Humans to Mars: Fifty Years of Mission Planning, 1950â2000
Chapter 5: Apogee
36
Monographs in Aerospace History
Boeingâs Behemoth
In January 1968, the Boeing Company published the
final report of a 14-month nuclear spacecraft study con-
ducted under contract to NASA Langley. The study was
the most detailed description of an interplanetary ship
ever undertaken.
10
As shown by the EMPIRE studies,
the propellant weight minimization promised by
nuclear rockets tended to encourage big spacecraft
designs. In fact, Boeingâs 582-foot long Mars cruiser
marked the apogee of Mars ship design grandiosity.
At Earth-orbital departure, Boeingâs behemoth would
include a 108-foot-long, 140.5-ton piloted spacecraft
and a 474-foot-long propulsion section made up of five
Primary Propulsion Modules (PPMs). The entire space-
craft would weigh between 1,000 and 2,000 tons, the
exact weight being dependent upon the launch oppor-
tunity used. Each 33-foot-diameter, 158-foot-long PPM
would hold 192.5 tons of liquid hydrogen. A 195,000-
pound-thrust NERVA engine with an engine bell 13.5
feet in diameter would form the aft 40 feet of each
PPM. The six-person piloted spacecraft would consist of
a MEM lander, a four-deck Mission Module, and an
Earth Entry Module.
Three PPMs would constitute Propulsion Module-1
(PM-1); two would constitute PM-2 and PM-3, respec-
tively. PM-1 would push the ship out of Earth orbit
toward Mars, then detach; PM-2 would slow the ship so
that Marsâ gravity could capture it into orbit, then it
would detach; and PM-3 would push the ship out of
Mars orbit toward Earth. At Earth, the crew would sep-
arate in the Apollo CM-based Earth Entry Module,
reenter Earthâs atmosphere, and splash down at sea.
Six uprated Saturn V rockets would place parts for
Boeingâs Mars ship in Earth orbit for assembly.
Assembly crews and the flight crew would reach the
spacecraft in Apollo CSMs launched on Saturn IB
rockets. The 470-foot-tall uprated Saturn V, which
would include four solid-fueled strap-on rockets, would
Chapter 5: Apogee
Figure 12âIn January 1968, Boeing proposed this complex Mars expedition plan using nuclear rockets and an opposition-class
trajectory. The companyâs Mars ship would measure nearly 200 meters long and support a crew of six. (Integrated Manned
Interplanetary Spacecraft Concept Definition, Vol. 1, Summary, D2-113544-1, Boeing Company, Aerospace Group, Space
Division, Seattle, Washington, p. 7.)
be capable of delivering 274 tons to a 262-mile circular
Earth orbit. Boeing envisioned modifying KSC Saturn
V launch pads 39A and 39B to launch the uprated
Saturn V, and building a new Pad 39C north of the
existing pads.
The companyâs report listed opportunities for nine
Venus-swingby, one conjunction-class, and five opposi-
tion-class Mars expeditions between November 1978
and January 1998. The conjunction-class mission would
last 900 days, while the Venus-swingby and opposition-
class missions would last from 460 to 680 days.
Boeing envisioned using the MOR mission plan NASA
Lewis used in its 1959-1961 studies. The MEM for
descending to Mars from Boeingâs orbiting Mars ship
was designed for MSC between October 1966 and
August 1967 by North American Rockwell (NAR), the
Apollo CSM prime contractor.
11
NARâs MEM report,
published the same month as the Boeing report, was
the first detailed MEM study to incorporate the
Mariner 4 results. Cost minimization was a factor in
NARâs MEM design. The company proposed a 30-foot-
diameter lander shaped like the conical Apollo CM.
The Apollo shape, it argued, was well understood and
thus would require less costly development than a
novel design.
The lightest NAR MEM (33 tons) would carry only
enough life support consumables to support two people
on Mars for four days, while the heaviest (54.5 tons)
was a four-person, 30-day lander. Like the Apollo Lunar
Module (and many previous MEM designs), NARâs
MEM design included a descent stage and an ascent
stage. The MEM would contain two habitable areasâ
the ascent capsule and the descent stage lab compart-
37
Humans to Mars: Fifty Years of Mission Planning, 1950â2000
Chapter 5: Apogee
Figure 13âCutaway of North American Rockwellâs 1968 Mars lander. Based on the Apollo Command Module shape, its design
incorporated new Mars atmosphere data gathered during the 1965 Mariner 4 automated Mars flyby. (Manned Exploration
Requirements and Considerations, Advanced Studies Office, Engineering and Development Directorate, NASA Manned
Spacecraft Center, Houston, Texas, February 1971, p. 5-3.)
38
Monographs in Aerospace History
ment. The ascent capsule would include an Apollo dock-
ing unit for linking the MEM to the mothership, and
the lab compartment would include an airlock for
reaching the Martian surface.
The MEMâs Apollo-style bowl-shaped heat shield
would protect it from friction heating during Mars
atmosphere entry. To reduce cost, NAR proposed to
develop a single heat shield design for both flight
tests in Earthâs atmosphere and Mars atmosphere
entry. This meant, of course, that the shield would be
more robust, and thus heavier, than one designed
specifically for Mars atmosphere entry. During Mars
atmosphere entry the crew would feel seven Earth
gravities of deceleration.
After atmospheric entry, the MEM would slow its
descent using a drogue parachute followed by a larger
ballute (balloon-parachute). At an altitude of 10,000
feet the ballute would detach. The MEMâs descent
engine would fire; then two of the astronauts would
climb from their couches to stand at controls and pilot
the MEM to touchdown. The company proposed using
liquid methane/liquid oxygen propellants that would
Chapter 5: Apogee
Figure 14âNorth American Rockwellâs plan for landing on Mars and returning to Mars orbit. The companyâs lander, a two-stage
design, would support up to four astronauts on Mars for up to 30 days and return to the orbiting mothership with up to 300
pounds of rocks. (Integrated Manned Interplanetary Spacecraft Concept Definition, Vol. 4, System Definition, D2-113544-4,
Boeing Company, Aerospace Group, Space Division, Seattle, Washington, January 1968, p. 145.)
offer high performance but not readily boil off or
decompose. The MEM would carry enough propellants
for two minutes of hover. Its six landing legs would
enable it to set down safely on a 15-degree slope.
For return to the mothership in Mars orbit, the crew
would strap into the ascent capsule with their Mars
samples and data. The ascent stage engine would
ignite, burning methane/oxygen propellants from eight
strap-on tanks. The ascent stage would blast away
from the descent stage, climb vertically for five sec-
onds, then pitch over to steer toward orbit. Once
empty, the strap-on tanks would fall away; the ascent
engine would then draw on internal tanks to complete
Mars orbit insertion and rendezvous and docking with
the mothership.
NAR had MEM development commencing in 1971 to
support a 1982 Mars landing. The company envisioned
a MEM flight test program using six MEM test articles
and a range of rockets, including three two-stage
Saturn Vs. The 1979 piloted MEM entry and landing
test, for example, would have a fully configured MEM
launched into Earth orbit on a two-stage Saturn V with
a piloted CSM on top. In orbit the CSM would detach,
turn, and dock with the MEM for crew transfer. The
crew would then cast off the CSM and fly the MEM to
landing on Earth.
Boeing scheduled the first Mars expedition for 1985-
1986, with Mars expedition contract awards in 1976,
and Mars hardware tests in low-Earth orbit beginning
in 1978. NAR estimated development cost of its MEM
at $4.1 billion, while Boeingâs study placed total Mars
program cost at $29 billion.
End of an Era
As Aerospace Technology magazine put it in May 1968,
âIf the political climate in Washington for manned
planetary missions is as bleak as the initial congres-
sional budget hearings indicate, the [NAR MEM]
study is . . . likely to be the last of its type for at least
a year.â
12
In fact, it was the last until the late 1980s. As
the battle over the FY 1968 budget during the summer
of 1967 made abundantly clear, a $29-billion Mars pro-
gram enjoyed support in neither the Johnson White
House nor the Congress. Events in 1968 made even
more remote the possibility that the U.S. might take on
a new Apollo-scale space commitment.
On 30 January 1968, immediately after Boeing and
NAR published their reports, North Vietnam invaded
South Vietnam on the eve of Tet, the lunar new year.
Though repulsed by U. S. and South Vietnamese forces,
the large-scale offensive drove home to Americans and
the Johnson White House that American involvement
in Indochina would likely grow before it shrank.
At the end of May, the Defense Department asked for
a $3.9-billion supplemental appropriation. Of this,
$2.9 billion was earmarked to pay for the Tet
Offensiveâthe Defense Department needed, for
example, to replace 700 destroyed helicoptersâwhile
$1 billion would beef up U.S. defenses in South Korea
following the Pueblo incident, in which North Korea
seized a U.S. ship.
13
A total of 14,592 American sol-
diers had been killed in Vietnam by the close of 1968,
by which time the total U.S. forces in Indochina stood
at more than half a million.
There was also trouble at home. Johnson was a politi-
cal casualty of Tet and other troubles shaking the
nation. On 31 March 1968, he announced that he
would not stand for reelection. On 4 April 1968, civil
rights leader Martin Luther King Jr. was gunned down
in Memphis, Tennessee; his death triggered racial vio-
lence across the country. That same month students at
Columbia University in New York seized buildings to
protest the Vietnam War in one of more than 200
major demonstrations at some 100 universities during
the year. On 6 June 1968, Democratic Party front-run-
ner Robert Kennedy was shot in Los Angeles. In
August, antiwar protesters disrupted the Democratic
National Convention.
Near the start of the FY 1969 budget cycle in early
February 1968, as American and South Vietnamese
forces pushed back the North Vietnamese, James Webb
testified to the House Space Committee, where a $4 bil-
lion FY 1969 NASA budget was, according to one com-
mittee staffer, a âfait accompli.â He reminded the
Committee that
NASAâs 1969 authorization request, at the
$4.37-billion level, is $700 million below the
amount requested last year. NASA expendi-
tures for Fiscal 1969 will be down $230 million
39
Humans to Mars: Fifty Years of Mission Planning, 1950â2000
Chapter 5: Apogee
from this year, $850 million from last year, and
$1.3 billion less than in Fiscal 1966. The NASA
program has been cut. I hope you will decide it
has been cut enough . . . .
14
In testimony to the Senate Appropriations Committee
in May, after the House approved a $4-billion NASA
budget, Webb told the Senators that President Johnson
had directed him to acquiesce to the cut, then
expressed concern over NERVAâs future.
15
The nuclear
rocket stayed alive in early June 1968 only after a
lengthy Senate floor battle waged by Howard Cannon
(Democrat-Nevada), whose state included the NRDS.
Webb told the Senate Appropriations Committee later
that month that the $4-billion NASA budget would
require halting Saturn V production for a year and can-
celing NERVA. In an attempt to rally NERVA support-
ers to approve their engineâs ride into space, he added
that âto proceed with NERVA while terminating
Saturn V cannot be justified.â
16
On 1 August 1968, Webb turned down George Muellerâs
request to make long lead-time purchases for manufac-
ture of two more Saturn Vâs, the sixteenth and seven-
teenth in the series. He informed the OMSF chief that
production would halt with the fifteen already allotted
for the Apollo lunar program.
17
A week later Webb told
Congress that âthe future is not brightâ for the Saturn
rockets.
18
At a White House press conference on 16 September
1968, Webb announced that he would step down after
nearly 8 years as NASA Administrator. He told journal-
ists that he left the Agency âwell prepared . . . to carry out
the missions that have been approved . . . . What we have
not been able to do under the pressures on the budget
has been to fund new missions for the 1970s . . . .â
19
Thomas Paine Takes Charge
The final FY 1969 NASA budget was $3.995 billion,
making it the first below $4 billion since 1963. This was
more than $370 million below NASAâs request, but
almost exactly what Johnson had told Webb to accept
in May. The Saturn V production line went on standby.
The nuclear rocket program received $91.1 million, of
which $33.1 million came from NASA funds.
NASA Deputy Administrator Thomas Paine became
Acting NASA Administrator upon Webbâs departure on
7 October. Webb, a 25-year veteran of Federal govern-
ment service, had described Paine as one of a ânew
breed of scientist-administrators making their way into
government.â
20
Formerly director of General Electricâs
TEMPO think tank, he had entered government ser-
vice through a program for recruiting managers from
industry.
Paine had become Webbâs Deputy
Administrator in March 1968, replacing Robert
Seamans. When he took over NASA from Webb, Paine
had seven months of Federal government experience.
Immediately after taking NASAâs reins, Paine told the
Senate Space Committee that he would seek a $4.5 bil-
lion NASA budget in FY 1970, followed by annual
increases leading to a $5.5-billion budget in FY 1975.
Paine said that he wanted a six- to nine-man space sta-
tion serviced by Apollo CSMs in the mid-1970s. George
Mueller also testified, calling for a $4.5-billion NASA
budget in FY 1970. He said that this was necessary to
avoid a gap in piloted flights after the Apollo lunar
landings.
21
On 30 October 1968, the Budget Bureau completed a
âhighlightsâ paper on âmajor aspects of National
Aeronautics and Space operations which warrant
attention at an early point in 1969â for President
Johnsonâs successor. The paper noted that âpressure is
mounting to budget significant sums for follow-on
manned space flight activities.â It stated that âthe
advantages of nuclear propulsion do not begin to
approximate the costs for missions short of a manned
Mars landing. No national commitment has been made
to undertake this mission[,] which would cost $40-
$100B[illion] . . . nevertheless, pressures are strong in
NASA, industry, and Congress to undertake the devel-
opment of the nuclear rocket.â
22
Republican Richard Nixon defeated Hubert Humphrey,
Johnsonâs Vice President, for the White House in
November. Though Apollo 7 had triumphantly returned
NASA astronauts to orbit in October, space had been
overshadowed as a campaign issue by the war, the
economy, student revolt, and many other âdown-to-
Earthâ issues. Nixon had promised a tax cut, which
promised to place yet more pressure on Federal agen-
cies to cut spending.
40
Monographs in Aerospace History
Chapter 5: Apogee
Six weeks after the election, in the Johnson
Administrationâs twilight days, space flight won back
the front page. On 21 December 1968, Apollo 8 astro-
nauts Frank Borman, James Lovell, and William
Anders became the first people to launch into space on
a Saturn V rocket and the first humans to orbit a world
other than Earth. The Apollo 8 CSM dropped behind
the Moon early on 24 December and fired its engine for
four minutes to slow down and allow the Moonâs grav-
ity to capture it into lunar orbit.
Thirty-five minutes after the spacecraft passed beyond
the Moonâs limb, it emerged from the other side. As it
did, Earth rose into view over the hilly lunar horizon,
and the crew snapped their planetâs picture. Lovell
described the Moon to people on Earth as âessentially
gray, no color; looks like plaster of Paris or sort of gray-
ish deep sand.â
23
Later, in one of the most memorable
moments of the space age, the crew took turns reading
to the world from the biblical book of Genesis. Early on
Christmas Day 1968, after 10 lunar orbits, the Apollo 8
crew fired their CSMâs engine to escape the Moonâs
gravitational pull and fall back to Earth.
Originally Apollo 8 was intended as an Earth-orbital test
of the Saturn V and the Lunar Module Moon lander, but
the Lunar Module was not ready. Sending Apollo 8 to
orbit the Moon was first proposed in August 1968 by
George Low, director of the Apollo Spacecraft Program
Office at MSC, and was eagerly promoted by Tom Paine
despite initial skepticism from NASA Administrator
Webb.
24
Because the crew lacked a Lunar Module, they
lacked the backup propulsion and life support systems it
could provide. These would come in handy during
James Lovellâs next flight to the Moon on Apollo 13 in
April 1970.
The image of Earth rising into view over the pitted gray
Moon featured prominently on end-of-year magazines
and newspapers. It formed a counterpoint of fragile
beauty and bold human achievement that accentuated
the war, dissent, and assassinations of 1968. This was
reflected in Nixonâs first inaugural speech on 20
January 1969:
We have found ourselves rich in goods, but
ragged in spirit; reaching with magnificent
precision for the Moon, but falling into rau-
cous discord on Earth. We are caught in war,
wanting peace. We are torn by divisions,
wanting unity.
25
Democrat Paine submitted his resignation pro forma
when Republican Nixon took office. Surprisingly, Nixon
did not accept it. Though Aviation Week & Space
Technology reported that Nixon was impressed by the
job Paine had done since coming to NASA, the real rea-
sons were apparently less meritorious.
26
Nixon had
never shown much interest in space and could find no
ideologically suitable replacement who wanted to head
NASA. He may also have desired to have a Democrat in
place to blame if the Kennedy/Johnson Apollo program
failed.
27
Paine was confirmed as NASA Administrator
in March 1969.
Being a Democrat in a Republican administration was
enough to leave Paine in a weak position. On top of
that, however, Paine was a Washington neophyte.
Webb had been wily, a Washington insider given to
deal-making; Paine was an idealist given to emotive
arguments. Paine was, according to NASA Historian
Roger Launius, âevery bit as zealous for his cause as
had been his namesake.â Furthermore, he was âunwill-
ing to compromise and . . . publicly critical of the
[Nixon] administrationâs lack of strong actionâ with
regards to space.
28
He excoriated his Center directors
for lacking boldness. He considered this disloyal to his
view of America, the expansive country, ready to tackle
any challenge.
29
To Paine, the late 1960s was not a time to try menâs souls.
He complained to the Washington Evening Star of âwhat
I would call almost a national hypochondria . . . in many
ways crippling some of the forward-looking things weâre
able to do . . . I feel that one of the very highest priority
matters is the war on poverty and the problems of the
cities. But in the meantime weâre making . . . a lot of
progress in the civil rights area and really, this
nation is a good deal healthier than weâre giving it
credit for today.â
30
Paine tried to use the excitement generated by Apollo
8 as a lever to gain Nixonâs commitment to an expan-
sive post-Apollo future for NASA. His efforts were
countered by voices counseling caution. Nixon had
appointed âtransition committeesâ to help chart a
course for his new Administration. On 8 January 1969,
the Task Force on Space transition committee, chaired
by Charles Townes, handed in its report. The Task
41
Humans to Mars: Fifty Years of Mission Planning, 1950â2000
Chapter 5: Apogee
Force, made up of 13 technologists and scientists, re-
commended against new starts and proposed a steady
NASA budget of $4 billion per year âa rather frugal
amountâ equivalent to âthree-quarters of one percent
of GNP [Gross National Product].â
31
The Task Force counseled continued lunar exploration
after the initial Apollo Moon landings and advised
Nixon to postpone a decision on a large space station
and the reusable shuttle vehicle needed to resupply it
economically. The primary purpose of the station was, it
said, âto test manâs ability for an extended spaceflight
over times of a year or more, so that the practicality of
a manned planetary mission could be examined.
However, the desirability of such a mission is not yet
clear . . . .â
32
The Task Force recommendations resembled those in
the February 1967 PSAC report, and with good rea-
sonâthe membership lists of the two groups were
almost identical. One new addition was Robert
Seamans, Secretary of the Air Force, who had been
NASA Deputy Administrator when the PSAC had sub-
mitted its 1967 report.
Even as the Task Force presented its recommendations
to Nixon, Paineâs optimistic plans for NASAâs FY 1970
budget foundered. President Johnsonâs FY 1970 budget
request for NASA, released 15 January 1969, was $3.88
billionâ$800 million less than the $4.7 billion âopti-
mumâ figure Paine had given the Budget Bureau in
November and more than $100 million less than what
Paine had said was the âminimum acceptable.â When
Nixonâs Budget Bureau chief, Robert Mayo, asked
agency heads a week later to further trim the Johnson
budget, Paine pushed for a $198-million increase. Mayo
quickly rebuffed Paineâs request.
33
Nixonâs FY 1970
budget went to Congress on 15 April. NASAâs share was
$3.82 billion, of which Congress eventually appropriat-
ed $3.75 billion.
Space Task Group
Paine pointed to the Task Force on Space report as an
example of what he did not want for NASAâs future.
34
At
a NASA meeting on space stations held in February at
Langley, Paine invoked instead von Braunâs Collierâs
articles.
35
Following the meeting, Aviation Week &
Space Technology magazine reported that NASA
planned a 100-person space station by 1980, with first
12-person module to be launched on a modified Saturn
V in 1975.
36
Nixonâs science advisor, Lee Dubridge, tried to get
authority to set NASAâs future course, in part because
he sensed Paineâs aims were too expansive, but Paine
protested. On 13 February 1969, President Nixon sent
a memorandum to Dubridge, Paine, Defense Secretary
Melvin Laird, and Vice President Spiro Agnew, asking
them to set up a Space Task Group (STG) to provide
advice on NASAâs future.
37
On 17 February, Nixon
solicited Paineâs advice on the agencyâs direction.
Paineâs long, detailed letter of 26 February sought to
step around the STG process and secure from Nixon
early endorsement of a space station.
38
In his
response, Nixon politely reminded Paine of the newly
formed STG.
39
STG meetings began on 7 March 1969. In addition to
the four voting members, the group included
observers: Glenn Seaborg of the AEC; U. Alexis
Johnson, Under Secretary of State for Political Affairs;
and, most influential, the Budget Bureauâs Mayo.
Robert Seamans stood in for Melvin Laird. The STG
chair was Agnew, another Washington neophyte.
Misreading the Vice Presidentâs importance within the
Nixon Administration, Paine focused his efforts on
wooing Agnew to his cause. Much of the STGâs work
was conducted outside formal STG meetings, which
occurred infrequently.
NASAâs STG position became based on the Integrated
Program Plan (IPP) developed by Muellerâs OMSF,
which was first formally described to Paine in a report
dated 12 May.
40
Mueller attributed many of its concepts
to a NASA Science and Technical Advisory Council
meeting held in La Jolla, California, in December 1968.
Though concerned mostly with Earth-orbital and cis-
lunar missions, the report proposed that âthe subsys-
tems, procedures and even vehiclesâ for such missions
âbe developed with a view towards their possible use in
a future planetary program . . . .â
41
The IPP schedule was aggressive even by 1960s Moon
race standards. Between 1970 and 1975, NASA would
conduct a dozen Apollo lunar expeditions and launch
and operate three AAP space stationsâtwo in Earth
orbit and one in lunar polar orbit. The year 1975 would
see the debut of the reusable Earth-orbital Space
42
Monographs in Aerospace History
Chapter 5: Apogee
43
Humans to Mars: Fifty Years of Mission Planning, 1950â2000
Shuttle, which could carry a 25-ton, 40-foot-long, 22-
foot-wide payload in its cargo bay.
Shuttle payloads would include a standardized space
station module housing up to 12 astronauts, a propul-
sion module usable as a piloted Moon lander or Space
Tug, and tanks containing liquid hydrogen propellant
for the NERVA-equipped Nuclear Shuttle, which would
first reach Earth orbit on an uprated Saturn V in 1977.
Significantly, Muellerâs IPP gave NERVA a non-Mars
mission as part of a larger reusable transportation sys-
tem in cislunar space. Up to 12 astronauts would con-
duct a Mars flight simulation aboard the Space Station
in Earth orbit from 1975 to 1978, and 1978 would see
establishment of a Lunar Base.
By 1980, 30 astronauts would live and work in cis-
lunar space at any one time. Four Nuclear Shuttle
flights and 42 Space Shuttle flights per year would
support the Space Station Program. Six Nuclear
Shuttle flights, 48 Space Shuttle flights, and eight
Space Tug Moon lander flights per year would support
the Lunar Base Program.
NASAâs Big Gun
Paine liked Muellerâs ambitious IPP. He asked Wernher
von Braun to make it even more expansive by building
a Mars mission concept onto it in time for a 4 August
presentation to the STG. The presentation was timed to
capitalize on the enthusiasm and excitement generated
by the first Apollo Moon landing mission, which was set
to lift off on 16 July 1969.
Paine saw von Braun as âNASAâs big gun.â He believed
that the space flight salesmanship for which the
German-born rocketeer was famous could still help
shape the future of American space flight as it had in
the previous two decades. According to Von Braun, âit
was an effort of a very few weeks to put a very consis-
tent and good and plausible story together.â
42
Meanwhile, Paineâs efforts to woo Agnew were, it
appeared, beginning to pay off. At the Apollo 11 launch,
the Vice President spoke of his âindividual feelingâ that
the United States should set âthe simple, ambitious,
optimistic goal of a manned flight to Mars by the end of
the century.â
43
On 20 July, Apollo 11 Commander Neil Armstrong and
Lunar Module Pilot Edwin âBuzzâ Aldrin landed the
spider-like Lunar Module Eagle on the Moonâs Sea of
Tranquillity. At the start of humanityâs first two-hour
Moon walk, Aldrin described the landscape as a âmag-
nificent desolation.â The astronauts remained at
Tranquillity Base for 21 hours before rejoining
Command Module Pilot Michael Collins aboard the
CSM Columbia in lunar orbit. On 24 July 1969, they
splashed down safely in the Pacific Ocean, achieving
the goal Kennedy had set eight years before.
In reporting the Apollo 11 landing, the Los Angeles
Herald-Examiner pointed to space-age spin-offs, such
as ânew paints and plastics,â then predicted that âthe
Mars goal should bring benefits to all mankind even
greater than the . . . [M]oon program.â
44
The
Philadelphia Inquirer anticipated opposition to a Mars
program; it asked, âwill the inspiration be abandoned
before the veiled censure of those who seem to suggest
the solution of all human dilemmas lies in turning
away from space to other priorities?â
45
Aviation Week & Space Technology reported that â[s]pace
officials sense that public interest is near an all-time
high . . . .â
46
Yet polls taken at the time did not indicate
strong public support for Mars exploration. A Gallup poll
showed that the majority of people polled aged under 30
years favored going on to Mars; however, a larger major-
ity of those over 30 opposed. Taken together, 53 percent
of Americans opposed a Mars mission, 39 percent
favored it, and 8 percent had no opinion.
47
In addition to the polls, new automated probe data sup-
plied Mars mission detractors with ammunition. The
Mariner 6 spacecraft had left Earth on 24 February,
just before STG meetings began. On 31 July 1969, as
Paine and von Braun put the finishing touches on their
4 August pitch, it flew over the southern hemisphere of
Mars, snapping 74 grainy images of a forbidding land-
scape pocked by craters. A feature known to Earth-
based telescopic observers as Nix Olympica (âthe
Olympian Snowsâ) appeared as a 300-mile crater with
a bright central patch.
The spacecraftâs twin, Mariner 7, had left Earth on 26
March. It flew over Marsâ southern hemisphere on 5
August 1969, snapping 126 images of the smooth-
floored Hellas basin, the heavily cratered Hellespontus
region, and the south pole ice cap. The probes seemed
Chapter 5: Apogee
to confirm the pessimistic picture painted by Mariner 4
in 1965. The New York Times noted that NASA had
âbegun drumming up pressure to spend huge sums
required to send men to Mars in the early 1980s . . . .
But the latest Mariner information makes the possibil-
ity of life on Mars much less than it seemed even a
week ago, thus removing much of the original motiva-
tion for such a project.â
48
NASAâs 4 August STG presentation had three parts,
lasted 55 minutes, and took into account neither the
opinion polls nor the new Mars data. In the first part,
Paine spent 20 minutes describing the âmystery, chal-
lenge, rich potential, and importance to man of the
solar systemâ and âhow the United States can move
from [the] start represented by Apollo to exploration of
the entire solar system with a program requiring only
a modest investment of our national resources.â
49
Von Braun followed Paine and spent 30 minutes
describing a piloted Mars expedition in 1982. His pres-
entation formed the heart and soul of NASAâs STG
pitch.
50
In retrospect, it also marked the apogee of von
Braunâs career.
Von Braun drew on a sizable library of conceptual Mars
spacecraft art generated in the Marshall Future
Projects Office to show Mayo, Dubridge, Seamans,
Johnson, Seaborg, and Agnew vehicles similar to the
Boeing Mars cruiser and the NAR MEM. In his IPP-
based plan, the MEM was the only piece of hardware
applicable only to Mars flight. All other vehicle ele-
ments would, he explained, be developed for cislunar
roles. MEM go-ahead in 1974 would mark de facto com-
mitment to a 1982 Mars expedition. The first space sta-
tion module, the design of which would provide the
basis for the Mars ship Mission Module, would fly in
1975, as would the first Earth-orbital Space Shuttle.
The year 1978 would see the MEM test flight; then, in
1981, the first Mars mission would depart Earth orbit
for a Mars landing in 1982.
The Mars mission would employ two Mars spacecraft
consisting of three Nuclear Shuttles arranged side by
side and a Mission Module. The complete spacecraft
would measure 100 feet across the Nuclear Shuttles
and 270 feet long. All modules would reach orbit on
upgraded Saturn V rockets. After the twin expedition
ships were assembled, reusable Space Shuttles would
launch water, food, some propellant, and two six-person
crews to the waiting Mars ships. At Earth-orbit launch,
each ship would mass 800 tons, of which 75 percent was
hydrogen propellant.
Von Braun targeted Mars expedition departure for 12
November 1981. The port and starboard Nuclear
Shuttles would then fire their NERVA engines, achieve
44
Monographs in Aerospace History
Chapter 5: Apogee
Figure 15âTwin Mars ships blast their all-male crews from
Earth orbit using NERVA nuclear rocket stages. In August
1969, Wernher von Braun used images such as this to pres-
ent NASAâs vision of a Mars expedition in the 1980s to the
Space Task Group and to Congress. (NASA Photo MSFC-
69-PD-SA-176)
Figure 16âCompared with cramped Apollo spacecraft, the
lodgings proposed for NASAâs 1980s Mars ships were pala-
tial. In this cutaway, note the four-deck Mission Module
(center) and large conical Mars lander (right). (NASA
Photo S-69-56295)
45
Humans to Mars: Fifty Years of Mission Planning, 1950â2000
Trans-Mars Injection, and shut down and separate from
the center Nuclear Shuttle and Mission Module. They
would turn around and fire their engines again to slow
down and enter elliptical Earth orbit. A few days later
they would reach perigee (lowest point above the Earth)
at the original assembly orbit altitude, fire their engines
to circularize their orbits, and rendezvous with the
Space Station for refurbishment and re-use. The ships
would weigh 337.5 tons each after port and starboard
Nuclear Shuttle separation.
As in the Planetary JAG piloted flyby missions, the
nine-month coast to Mars would be âby no means an
idle phase.â The ships each would serve as âa manned
laboratory in space, free of the disturbing influences of
the Earth.â According to von Braun, â[t]he fact that
there will be two observation points, Earth and space-
craft, permits several possible experiments.â In addi-
tion, âas yet unidentified comets might be observed for
the first time.â
51
Von Braun had the twin Mars ships reaching Mars on
9 August 1982. Each would fire the NERVA engine on
its remaining Nuclear Shuttle to slow down and enter
Mars orbit. At Mars Orbit Insertion each spacecraft
would weigh 325 tons. The crews would then spend
two days selecting landing sites for the expeditionâs 12
automated Sample Return Probes. The probes would
land, retrieve samples uncontaminated by human
contact, and lift off, then deliver the samples auto-
matically to sterilized bio-labs on the ships for study.
If the samples contained no hazards, a three-man land-
ing party would descend to the surface in one of the
47.5-ton MEMs. The other would be held in reserveâ
von Braun explained that âcapability is provided for
one man to land a MEM and bring a stranded crew
back to the ship.â He promised that âManâs first step on
Mars will be no less exciting than Neil Armstrongâs
first step on the Moon.â
52
The astronauts would then spend between 30 and 60
days on Mars. Von Braun listed objectives for Martian
exploration, including the following:
âą Understand Martian geology âbecause Mars
probably closely paralleled the earth in origin
and . . . development.â
âą Search for lifeâvon Braun stated that âprelim-
inary data indicate that some lower forms of life
can survive in the Martian environment . . . in
isolated areas higher forms . . . may exist. Man
on Mars will [also] be able to study . . . the
behavior of terrestrial life forms transplanted to
the Martian environment.â
âą
âDrilling for . . . water will be an early objec-
tive . . . and its discovery would open many
possibilities . . . . For example, it might
become possible to produce rocket fuel for the
return trip on later missions.â
53
The landing party would lift off in the MEM ascent
stage using the descent stage as a launch pad. The
ascent stage would dock with the orbiting ship and the
crew would transfer 900 pounds of samples and equip-
ment, then would discard the expended ascent stage.
The ships would ignite their center Nuclear Shuttles to
leave Mars on 28 October 1982, after 80 days near the
planet. The ships would weigh 190 tons each prior to
Mars orbit departure.
Von Braun told the STG that the twin Mars ships
would fly by Venus on 28 February 1983, to use the
planetâs gravity to slow their approach to Earth, there-
by reducing the amount of braking propellant needed
to enter Earth orbit. During swingby the astronauts
would map Venusâ cloud-shrouded surface with radar
and deploy four automated probes.
Von Braun scheduled return to Earth for 14 August
1983. He noted that an Apollo-style direct reentry was
possible; however, until âa better assessment can be
made of the back contamination hazard (the return by
man of pathogens that might prove harmful to earth
inhabitants), a more conservative approach has been
planned, i.e., the return of the crew to earth orbit for a
quarantine period.â
54
The center Nuclear Shuttles
would place the Mission Modules in Earth orbit and
perform rendezvous with the Space Station, where doc-
tors would examine the astronauts. The Mars ships
would weigh 80 tons each at missionâs end, one-tenth of
their Earth-departure weight. Following their quaran-
tine period, the crew would return to Earth aboard a
Space Shuttle. The center Nuclear Shuttles, mean-
while, would be refurbished and reused.
He then looked beyond the first expedition, stating that
additional flights to Mars could occur during the peri-
ods 1983-84, 1986-87, and 1988-89. The 50-person Mars
Base might be established in 1989, in time for the 20th
Chapter 5: Apogee
46
Monographs in Aerospace History
anniversary of von Braunâs presentation. Von Braun
told the STG that NASAâs budget would peak at $7 bil-
lion per year in 1975, or about 0.6 percent of GNP, and
that it would level out at $5 billion in 1989, at which
time its share of GNP would be 0.3 percent.
55
This
assumed steady 4 percent annual growth in the U.S.
economy. In his closing remarks, Paine put the cost a
little higher than had von Braun; he told the other STG
members that â[t]his kind of program would be possible
for the United States with a budget rising to about $9
billion [per year] in the last half of the decade.â
56
âNow Is Not the Time . . .â
NASAâs vision was breathtaking, but stood little
chance of acceptance in 1969 America. Robert
Seamans appears to have been generally sympathetic
to Paineâs vision, yet cognizant of political and eco-
nomic realities. He arrived at the 4 August meeting
with a letter for Agnew laying out a less expansive
view of Americaâs future in spaceâone similar to the
recommendations made by the transition Task Force
in January. Seamans wrote, âI donât believe we should
commit this Nation to a manned planetary mission, at
least until the feasibility and need are more firmly
established. Experience must be gained in an orbiting
space station before manned planetary missions can
be planned.â Then he recommended against early com-
mitment to a space station.
Seamans advised instead that NASA should expand
AAP and continue lunar exploration âon a careful step-
by-step basis reviewing scientific data from one flight
before going to the next.â He differed from the transi-
tion Task Force by recommending âa program to study
by experimental means including orbital tests the pos-
sibility of a Space Transportation System that would
permit the cost per pound in orbit to be reduced by a
substantial factor (ten times or more).â
57
Aviation Week
& Space Technology had by this time already pre-
dicted that the STG would recommend a reusable
Space Shuttle as NASAâs post-Apollo focus.
58
On 5 August, the day Mariner 7 flew past Mars, Paine
and von Braun presented their pitch to the Senate
Space Committee. Clinton Anderson, its chair, had in
effect already responded to the presentation; on 29 July
1969, he said that ânow is not the time to commit our-
selves to the goal of a manned mission to Mars.â
59
Coming from Anderson, this was ominous and some-
what puzzling. The New Mexico Senator had backed
NASA since its birth, in large part because the Agency
gave the nuclear rocket program he supported funding
and a raison dâĂȘtre. His rejection of Mars placed him in
a dilemmaâhow could he back nuclear propulsion yet
not support what was widely seen as its chief mission?
Other Space Committee members had similar reac-
tions to NASAâs presentation. Senator Mark Hatfield
(Republican-Oregon) told Paine and von Braun that he
supported the space program, but was ânot really
ready, at this point . . . to make commitments . . . to
meet a deadline to get a man to Mars.â Senator
Margaret Chase Smith (Republican-Maine) named
Paineâs game, saying that the government âshould
avoid making long-range plans during this emotional
period [following Apollo 11] . . . otherwise we may
become involved in a crash program without the justi-
fication we had for Apolloâand therefore without the
full support of Congress.â
60
Despite the clear signals from Congress, the STG
remained split between Washington neophytes and old
hands, with the former stubbornly preaching Mars and
the latter counseling something less expansive. Robert
Mayo broke the deadlock when he proposed that the
group offer the President several pacing options con-
tingent on available funds.
61
Paine and Mueller then took their case to the public
with a presentation to the National Press Club. Mueller
painted a picture of NASAâs space activities in 1979,
when, he said, more than 200 people would work in
space at one time. Most would be scattered in facilities
between Earth orbit and the lunar surface; however, 12
would be en route to Mars in two ships.
62
Aviation Week
& Space Technology editor Robert Hotz attended the
Press Club talks and became swept up in NASAâs vision.
In his editorial following the talks he took a page from
Paineâs book, writing that
the Apollo 11 mission has opened an endless
frontier which mankind must explore. Man is
extending his domain from the 8,000-mile-
diameter of his home planet earth to the 8-
billion-mile diameter of the solar system . . . .
Hopefully [the President] will note that only
by setting extremely high goals have extraor-
dinary results been achieved . . . . We think
Dr. Paine made a telling point when he
warned against establishing future goals too
low.
63
Chapter 5: Apogee
Congress, meanwhile, voiced more reservations.
George Miller (Democrat-California), chair of the
House Committee on Science and Astronautics, did
not want âto commit to a specific time period for set-
ting sail to Mars.â Miller was not opposed to going to
Mars on principle; in fact, he believed it âhighly prob-
able that five, perhaps 10 years from now we may
decide that it would be in the national interest to
begin a carefully planned program extending over
several years to send men to Mars.â
64
J. W. Fulbright (Democrat-Arkansas), Committee on
Foreign Relations chair, sought to put Apollo in proper
perspective as an element of 1960s realpolitik: âThe
[Apollo 11] landing called forth a great deal of poetizing
about the human spirit bursting earthly bounds . . . . In
all this I perceive not humbug . . . but rather more sen-
tentiousness than plain hard truth. Americans went to
the Moon for a number of reasons of which, I am con-
vinced, the most important by far was to beat the
Russians.â
65
Sending American astronauts on to Mars
had nothing to do with beating the Russians. Therefore,
Fulbright saw little cause to support such a mission.
Americaâs Next Decades in Space
NASA released its report Americaâs Next Decades in
Space: A Report to the Space Task Group on 15
September 1969.
66
Paine was the principal author of
the report, which aimed to promote NASAâs STG posi-
tion. In retrospect the report marked the apogee of
NASA Mars expedition planning. With a note of pride
it pointed out that, in NASAâs first decade,
the American space program progressed from
the 31-pound Explorer 1 in earth orbit to
Apollo spacecraft weighing 50 tons sent out to
the moon [and] from manned flights of a few
thousand miles and 15-minute duration to
the 500,000 mile round-trip 8-day [Apollo 11]
mission which landed men on the [M]oon and
returned them safely to [E]arth.
67
The NASA report then appealed to President Nixon to
think of his place in history, and to see his decision as
an unprecedented opportunity:
At the moment of its greatest triumph, the
space program of the United States faces a cru-
cial situation. Decisions made this year will
affect the course of space activity for decades to
come . . . . This Administration has a unique
opportunity to determine the long-term future
of the Nationâs space progress. We recommend-
ed that the United States adopt as a continuing
goal the exploration of the solar system . . . . To
focus our developments and integrate our pro-
grams, we recommend that the United States
prepare for manned planetary expeditions in
the 1980s.
68
Not surprisingly, the NASA reportâs program closely
resembled the one Paine and von Braun described in
their 4 August STG presentation. Continued piloted
lunar exploration after Apollo would, the NASA report
proclaimed, âexpand manâs domain to include the
[M]oonâ by establishing a lunar base. This would lay
groundwork for a piloted Mars expedition in the 1980s.
As Mayo had proposed, the NASA report described
different program rates, each with a different date for
reaching Mars, the ultimate goal of all the programs.
The âmaximum rate,â in which money was no object
and only the pace of technology could slow NASAâs
rush to Mars, scheduled the first Mars expedition for
1981. Program I launched the first expedition in
1983, while Program II, the pacing option favored by
Agnew, put it in 1986. Program III was identical to
Program II, except that no date was specified for the
first Mars expedition.
The STG report proper, The Post-Apollo Space Program:
Directions for the Future, was also published on 15
September 1969. It had a split personality.
69
The main
body closely followed NASAâs Americaâs Next Decades in
Space reportânot surprisingly, since Paine was again
the principal author. The introductory âConclusions and
Recommendationsâ section, however, differed markedly
in tone and emphasis from the NASA-authored section.
This was because it was added in early September at
the insistence of senior White House staffers who did
not want to provide President Nixon with only ambi-
tious objectives from which to choose.
70
The âConclusions and Recommendationsâ section
acknowledged that NASA had âthe demonstrated
organizational competence and technology base . . . to
carry out a successful program to land man on Mars
within 15 yearsâ; however, it failed to advocate an
aggressive Mars program, recommending instead
sending humans to Mars âbefore the end of this cen-
tury.â At the same time, it cautioned that âin a bal-
47
Humans to Mars: Fifty Years of Mission Planning, 1950â2000
Chapter 5: Apogee
anced program containing other goals and activities,
this focus should not assume over-riding priority and
cause sacrifice of other important activity in times of
severe budget constraints.â
71
New space capabilities would be developed in a three-
phase program, to which the introductory section
attached no firm schedule. Phase 1 would see âexploita-
tion of existing capability and development of new
capability, maintaining program balance within avail-
able resources.â This would include continued âApollo-
typeâ lunar missions. New development would be based
on the principles of âcommonality, reusability, and econ-
omy.â Phase 2 was an âoperational phaseâ using new
systems in cislunar space with emphasis on âexploita-
tion of science and applicationsâ aboard space stations.
In Phase 3, âmanned exploration missions out of
[E]arth-[M]oon spaceâ would occur, âbuilding upon the
experience of the earlier two phases.â
72
The
âConclusions and Recommendationsâ section cau-
tioned,
Schedule and budgetary implications within
these three phases are subject to Presidential
choice and decision . . . with detailed program
elements to be determined in a normal annual
budget and program review process.
73
Nixonâs Response
Shortly after the Apollo 11 lunar landing, von Braun
told space policy analyst John Logsdon that
the legacy of Apollo has spoiled the people at
NASA . . . . I believe that there may be too many
people in NASA who at the moment are waiting
for a miracle, just waiting for another man on a
white horse to come and offer us another planet,
like President Kennedy.
74
Von Braun might have placed his boss in that category.
Paine placed great stock in the effect the NASA section
of the STG report would have on President Nixon.
Another documentâa lengthy memorandum by Mayo
dated 25 September 1969âapparently had greater
effect, however. Mayo told the President that NASA
had requested $4.5 billion for FY 1971 despite a $3.5-
billion cap imposed by his office. He then recommended
that Nixon âhold an announcement of your space deci-
sion until after you have reviewed the [STG] report rec-
ommendations specifically in the context of the total
1971 budget problem . . . .â Mayo added that he believed
the NASA sections of the STG report âsignificantly
underestimatedâ the costs of future programs.
75
In late September, Aviation Week & Space Technology
reported that NASA was hopeful that it might receive
a supplemental appropriation in FY 1970 to begin work
toward Mars.
76
In October this optimism led Mueller to
establish the Planetary Missions Requirements Group
(PMRG), which included representatives from NASA
Headquarters and several NASA field centers. The
PMRG, the successor to the Planetary JAG, first met
formally in December 1969. Its purpose was to blue-
print Mars mission concepts in the context of the STG
integrated plan.
77
By the time the PMRG met for the first time, however,
NASA had received bad news. On 13 November 1969,
Mayoâs Office of Management and Budget (OMB) (for-
merly the Budget Bureau) had informed Paine that
NASAâs FY 1971 request would be $1 billion shy of his
requestâjust $3.5 billion. Paine called the figure âunac-
ceptableâ and told Mayo that âthe proposed rationaleâ
for this budget figure âignores and runs counter to the
conclusions reached by the Space Task Group . . . the
OMB staff proposals would force the President to reject
the Space Program as an important continuing element
of his Administrationâs total program.â
78
Paine was compelled to acquiesce, however. On 13
January 1970, he briefed newsmen on NASAâs budget
ahead of Nixonâs FY 1971 budget speech. He termed
the $3.5 billion budget âsolid,â and announced that the
Saturn V rocket production line, already dormant,
would close down permanently.
79
This was a serious
blow to the nuclear rocket program. It meant that, in
addition to having no approved mission, it now had no
way to get into space. NASA subsequently began study
of using the Earth-orbital Space Shuttle to place
NERVA-equipped rocket stages into Earth orbit.
Paine also canceled the planned tenth lunar landing
mission, Apollo 20, so that its Saturn V could launch
the Skylab space station, and announced that the
Viking Mars probe would slip to a 1975 launch with a
1976 Mars landing. In an apparent effort to raise alarm
and fend off further cuts, Paine released a list of NASA
Center closures in order of priority. First to go would be
48
Monographs in Aerospace History
Chapter 5: Apogee
Ames, in Nixonâs California stronghold, and the last
three in order would be MSC, Marshall, and KSC.
80
In late January, just before Nixon unveiled his Federal
budget for FY 1971, NASA took another cut. When sent
to Capitol Hill on 2 February 1970, NASAâs portion of
the budget had fallen to $3.38 billion. In announcing
NASAâs budget, Nixon said that â[o]ur actions make it
possible to begin plans for a manned mission to Mars.â
81
In fact, the 1970-71 period would see NASAâs last for-
mal piloted Mars plan until the 1980s.
Nixon did not use his 22 January 1970 State of the
Union address to plot the way forward in space as
some in NASA had hoped that he might. His first pri-
ority, he said, was to âbring an end to the war in
Vietnam.â He also proposed to âbegin to make repara-
tions for the damage we have done to our air, to our
land, and to our waters.â
82
Apollo 8 pictures of blue
Earth rising over the barren Moon had become a ral-
lying point for the environmental movementânot, as
Paine had hoped, for space exploration. Paine was
unimpressed by Nixonâs environmentalist slant. He
told an industry group that â[w]e applaud the increase
in sewage disposal plants. But we certainly hope this
doesnât mean the nation has taken its eyes off the
stars and put them in the sewers.â
83
Nixon finally issued his policy on the post-Apollo
space program on 7 March 1970. Unlike Kennedyâs
1961 Moon speech, Nixonâs statement was broad and
vague, with no specifics about NASA funding. Rather
than endorse a specific target date for a piloted Mars
mission, he said that âwe will eventually send men to
explore the planet Mars.â The British weekly The
Economist reported that people at NASA âlooked like
children who got the jigsaw puzzle they were expecting
rather than the bicycle they were dreaming of.â
84
PSAC Recommends Shuttle
At the same time Nixon issued his space policy, his
PSAC issued The Next Decade in Space, a report
extolling the possibilities of a Space Shuttle-based space
program. The presidential advisory body acknowledged
that â[e]normous technological capabilities have been
built up in the Apollo Program,â but recommended âa
civilian space effort about half the magnitude of the
present level.â
85
The PSAC emphasized the military and
direct economic benefits of piloted space travel, which it
said could only be accrued by replacing virtually all
expendable rockets with a reusable Space
Transportation System (STS). This would include the
Space Shuttle and a reusable orbital tug.
The STS would allow âorbital assembly and ultimately
radical reduction in unit cost of space transportation,â
the PSAC stated, quoting a NASA/Defense Department
study that placed the cost per flight of the STS at $5
million, or 1 percent of the Saturn V cost.
86
At the time
the PSAC released its report, the U.S. could launch four
Saturn V rockets per year, each with a payload of about
100 tons. The PSAC reasoned that â[s]ince only ten
flights of the STS can in principle fulfill the role of two
Saturn V launches/year, this capability might be
reached soon after initial operation of the STS.â
87
The PSAC then addressed piloted Mars exploration,
writing that â[p]rudence suggests that the possibility of
undertaking a manned voyage to Mars be kept in mind
but that a national commitment to this project be
deferred at this time.â
88
The STS, it expected, âcould place
the equipment needed for the Mars mission in orbit with
one or two dozen launches and at a cost substantially
below that of a single Saturn V.â It also recommended
that the permanent space station it said should precede
a piloted Mars mission be deferred until after the STS
could be used to assemble it.
89
Despite the heavy reliance
it placed on the STS, the PSAC recommended deferring
a decision to build it until FY 1972.
In July 1970, Paine submitted his resignation. On 15
September the first anniversary of the release of the
STG and NASA reports, George Low took over as
Acting NASA Administrator. In February 1971,
Presidential Assistant Peter Flanigan was ordered to
find a NASA Administrator who would âturn down
NASAâs empire-building fervor and turn his attention
to . . . work[ing] with the OMB and White House.â
90
The Last Mars Study
The PMRG, meanwhile, continued low-level Mars expe-
dition planning. NASAâs post-Apollo Mars aspirations
died with a whimperâa call to NASA Centers partici-
pating in the PMRG for reports summing up their work.
PMRG work at MSC resided in the Engineering and
Development Directorateâs Advanced Studies Office
49
Humans to Mars: Fifty Years of Mission Planning, 1950â2000
Chapter 5: Apogee
50
Monographs in Aerospace History
under Morris Jenkins. MSC Associate Director of
Engineering Maxime Faget reviewed Jenkinsâ February
1971 report. In his introduction, Jenkins explained,
Official statements regarding the manned
Mars mission have always been conditioned by
an emphasis that there was no set time frame
for it. This together with problems of budget
constraints on the more immediate future pro-
grams and the overall posture of the space pro-
gram, influenced formal support for this study.
Justifiably, the formal support was always very
small and . . . non-continuous . . . .
91
The guiding principle of MSCâs PMRG study was
austerity. In general configuration its Mars ship
resembled Boeingâs 1968 behemoth, but chemical
propulsion stood in for nuclear. According to
Jenkins, âeverything [was] done to make [this study]
a useful point of departure when national priorities
and economic considerations encourage the mount-
ing of a manned Mars expedition.â
92
MSC targeted
its 570-day Mars expedition for the 1987-88 launch
opportunity, following an 11-year development and
test period beginning in the mid-1970s.
MSC assumed availability of a fully reusable Space
Shuttle based on Max Fagetâs âflybackâ design. The fly-
back shuttle would include a winged orbiter launched
on a winged booster. Both booster and orbiter would
carry astronauts. MSC envisioned a booster the size of
a 747 and an orbiter on the scale of a DC-9.
The study rejected launching Mars spacecraft compo-
nents in the 15-foot-diameter payload bay of the
orbiter because as many as 30 modules would have to
be launched separately and brought together in orbit,
necessitating a âcomplex and lengthy assembly and
checkout process.â
93
Instead, MSC proposed launch-
ing the Mars shipâs three 24-foot-diameter modules
on the back of the Shuttle booster with the aid of
Chemical Propulsion System (CPS) stages. Three
CPS stages would be launched into orbit without
attached modules.
The Shuttle booster would carry the CPS and attached
module (if any) partway to orbit, then separate to
Chapter 5: Apogee
Figure 17âLast gasp (for a while): NASAâs 1971 Mars spaceship design, the last until the 1980s, proposed to reduce cost
by using projected Space Shuttle technology and rejecting nuclear engines in favor of cheaper chemical propulsion.
(Manned Exploration Requirements and Considerations, Advanced Studies Office, Engineering and Development
Directorate, NASA Manned Spacecraft Center, Houston, Texas, February 1971, p. 5-2.)
return to the launch site. The CPS would then ignite to
achieve Earth orbit. Each CPS would weigh 30 tons
empty and hold up to 270 tons of liquid hydrogen/liquid
oxygen propellants. In keeping with the principle of
austerity, the CPS stages would use the same rocket
engine and propellant tank designs as the Shuttle
booster and orbiter, and do double duty as Mars ship
propulsion stages. Assembling the expeditionâs single
ship would need 71 Shuttle booster launches. Six would
launch the ship (three modules and six CPS stages),
and the remainder would carry Shuttle orbiters serving
as tankers for loading the CPS stages with propellants.
The assembled Mars ship would include a hangar for
automated probes and a MEM based on the 1968 NAR
design. For redundancy, its 55-ton, four-deck Mission
Module would be split into two independent pressur-
ized volumes, each containing a duplicate spacecraft
control station. Deck four would be the shipâs solar flare
radiation shelter. The 65-foot-long Electrical Power
System module would contain pressurized gas storage
tanks and twin solar arrays. The crew would rotate the
Mars ship end over end about twice per minute to pro-
duce artificial gravity in the Mission Module equal to
one-sixth Earthâs gravity (one lunar gravity).
Earth departure would require a series of maneuvers.
Maneuver 1 would expend two CPS stages to place the
Mars ship in elliptical âintermediate orbit.â Maneuver 2
and Maneuver 3 would use one CPS stageâthe first
would place the ship in elliptical âwaiting orbit,â and
the second would adjust the plane of the departure
path. Space tugs would later recover the three discard-
ed CPS stages for reuse. Maneuver 4 would place the
ship on a 6-month trajectory to Mars. The fourth CPS
would enter solar orbit after detaching from the Mars
ship and would not be recovered.
Slowing the ship so that Marsâ gravity could capture
it into a 200-mile by 10,000-mile orbit would expend
the fifth CPS. The elliptical orbit would require less
propellant to enter and depart than a circular one.
The five-person crew would spend 15 days in orbit
studying Mars and preparing the MEM for landing;
then three crewmembers would separate in the MEM,
leaving behind two to watch over the mothership.
The MEM crew would explore their landing site using
a pair of unpressurized electric rovers resembling the
Apollo Lunar Roving Vehicle, which was slated to be
driven on the Moon for the first time on Apollo 15 in
July 1971. During Mars surface excursions, one
crewmember would remain in the MEM while the
other two took out one rover each. This âtandem con-
voyâ arrangement would allow the Mars explorers to
avoid the âwalk backâ limit imposed on single-rover
traverses in the Apollo program. Walk back distance
was limited less by astronaut stamina than by the
amount of water and air the space suit backpacks could
hold. If one Mars rover failed, the functional rover
would return both astronauts to the MEM. Each rover
would include a hook for towing the failed rover back to
the MEM for repairs.
Rover maximum speed would be 10 miles per hour, and
total area available to two rovers would amount to
8,000 square miles, compared to only 80 square miles
for a single rover. Once every 15 days, a 36-hour tra-
verse of up to 152 miles would occur, with the astro-
nauts sleeping through the frigid Martian night on the
parked rovers in their hard-shelled aluminum space
suits. Jenkins did not attempt to estimate the amount
of sleep the astronauts might actually be able to
achieve during their overnight camping trips.
The astronauts would collect samples of rock and soil
with emphasis on finding possible life. According to the
MSC report, â[t]he potential for even elementary life to
exist on another planet in the solar system may . . . be
the keystone to the implementation of a manned plan-
etary exploration program . . . manâs unique capabili-
ties in exploration could . . . have a direct qualitative
impact on life science yield.â
94
After 45 days of surface exploration, the crew would
blast off in the MEM ascent stage and dock with the
mothership. Any specimens of Mars life collected would
be transferred to a Mars environment simulator. The
crew would discard the ascent stage; then the sixth
and final CPS would ignite to push the ship back
toward Earth. The MEM astronauts would remain
quarantined in one pressurized volume until the dan-
ger of spreading Martian contagion to the other astro-
nauts was judged to be past.
The MSC PMRG report received only limited distribu-
tion within NASA and virtually none outside the
Agency. Formal studies within NASA aimed at sending
humans to Mars would not occur again until the
Manned Mars Missions exercise in 1984 and 1985.
51
Humans to Mars: Fifty Years of Mission Planning, 1950â2000
Chapter 5: Apogee
52
Monographs in Aerospace History
Chapter 5: Apogee
NERVA Falls, Shuttle Rises
The OMBâs FY 1972 request for NASA was $3.31 bil-
lion. The budget slashed NERVA funding in favor of
continued Space Shuttle studies. Combined AEC-
NASA nuclear rocket funding plummeted to $30 mil-
lion split evenly between the two agencies. NASA and
the AEC had together requested $110 million. The
allotted budget threatened to place the NRDS on
standby and was considered by many sufficient only to
shut down the program.
In February 1971, Clinton Anderson held a hearing on
the cut in NASAâs NERVA funding. In his introductory
remarks, he lauded the nuclear rocket program as âone
of the most successful space technology programs ever
undertakenâ and pointed to the $1.4-billion investment
in nuclear propulsion technology since 1955.
95
Senator
Alan Bible (Democrat-Nevada) then pointed out that
the STG report called for nuclear rockets.
96
Acting NASA Administrator George Low took his
marching orders from the highest levels of the Nixon
White House. The Earth-orbital Shuttle had to come
first, he saidâwithout it NERVA had no ride to space.
He told the Senators that, âNERVA needs the Shuttle,
but the Shuttle does not need NERVA.â
97
Low denied that the funding cut would kill the pro-
gram, explaining that âuseful work on long lead-time
itemsâ could be accomplished.
98
There would, however,
be no technical progress during FY 1972, and possibly
none in FY 1973. âWe have not, as yet, been able to look
forward beyond that,â Low added.
99
Two months later, in May 1971, 21 members of
Congress wrote to President Nixon requesting more
funds for NERVA in FY 1972. When the White House
failed to respond, Congress of its own accord budgeted
$81 million for nuclear rockets, of which NASAâs por-
tion was $38 million. In October, however, the OMB
refused to release more than the $30 million the
Administration had requested. In November the OMB
stood by its FY 1972 nuclear propulsion request despite
protests from the Senate floor.
100
On 5 January 1972, President Nixon met with James
Fletcher,
Tom Paineâs successor as NASA
Administrator, at the âWestern White Houseâ in San
Clemente, California. Afterward, Fletcher read out
Nixonâs statement calling for an FY 1973 new start on
the Shuttle. The announcementâs venue was signifi-
cantâCalifornia, a state of many aerospace firms, was
vital to Nixonâs 1972 reelection bid.
101
Nixon pointed out
that âthis major new national enterprise will engage
the best efforts of thousands of highly skilled workers
and hundreds of contractor firms over the next several
years.â Fletcher added that it was âthe only meaningful
new manned program that can be accomplished on a
modest budget.â
102
First flight was scheduled for 1978.
Nixon sent his FY 1973 budget to Capitol Hill on 24
January 1972. As its supporters had feared, the budget
contained no funds for NERVA. Anderson, nuclear
propulsionâs greatest champion, was ill and could not
defend it. The last NERVA tests occurred in June and
July of 1972. Anderson retired from the Senate at the
end of 1972. The FY 1974 budget terminated what
remained of the U.S. nuclear rocket program.
103
With both NERVA and Saturn V goneâthe last Saturn
V flew in May 1973âNASAâs piloted space flight ambi-
tions collapsed back to low-Earth orbit. Yet the Agency
did not cease to strive toward Mars. As we will see in
the next chapter, NASAâs robot explorers conducted the
first in-depth Mars exploration in the 1970s, holding
open the door for renewed piloted Mars planning.
Additional automated missions will most cer-
tainly occur, but the ultimate scientific study of
Mars will be realized only with the coming of
manâman who can conduct seismic and elec-
tromagnetic sounding surveys; who can launch
balloons, drive rovers, establish geologic field
relations, select rock samples and dissect them
under the microscope; who can track clouds and
witness other meteorological transients; who
can drill for permafrost, examine core tubes,
and insert heat-flow probes; and who, with his
inimitable capacity for application of scientific
insight and methodology, can pursue the quest
for indigenous life forms and perhaps discover
the fossilized remains of an earlier biosphere.
(Benton Clark, 1978)
1
The New Mars
In the 1960s, most automated missions beyond low-
Earth orbitâthe Rangers, Surveyors, and Lunar
Orbitersâsupported the piloted Apollo program. In the
1970s, as NASAâs piloted program contracted to low-
Earth orbit, its automated program expanded beyond
the Moon. Sophisticated robots flew by Mercury,
Jupiter, and Saturn, and orbited and landed on Venus
and Mars.
Though they were not tailored to serve as precursors to
human expeditions in the manner of the Rangers,
Surveyors, and Lunar Orbiters, the automated missions
to Mars in the 1970s shaped the second period of piloted
Mars mission planning, which began in about 1981. The
first of these missions, Mariner 9, took advantage of the
favorable Earth-Mars transfer opportunity associated
with the August 1971 opposition to carry enough pro-
pellant to enter Mars orbit. It was launched from Cape
Kennedy on 30 May 1971.
In September, as Mariner 9 made its way toward Mars,
Earth-based astronomers observing the planet through
telescopes saw a bright cloud denoting the onset of a
dust storm. By mid-October it had become the largest
on record. Wind-blown dust obscured the entire sur-
face, raising fears that Mariner 9 might not be able to
map the planet from orbit as planned.
2
On 14 November 1971, after a 167-day Earth-Mars
transfer, Mariner 9 fired its engine for just over 15 min-
utes to slow down and become Marsâ first artificial
satellite. Dust still veiled the planet, so mission con-
trollers pointed the spacecraftâs cameras at the small
Martian moons Phobos and Deimos. In Earth-based
telescopes they were mere dots nearly lost in Marsâ red
glare. In Mariner 9 images, Phobos was marked by par-
allel cracks extending from a large crater. Apparently
the impact that gouged the crater had nearly smashed
the little moon. Deimos, Marsâ more distant satellite,
had a less dramatic, dustier landscape.
The giant dust storm subsided during December,
theatrically unveiling a surprising world. Mars was
neither the dying red Earth espoused by Percival
Lowell nor the dead red moon glimpsed by the flyby
Mariners.
3
From its long-term orbital vantage point,
Mariner 9 found Mars to be two-faced, with smooth
northern lowlands and cratered southern highlands.
The missions to the Moon confirmed that a relation-
ship exists between crater density and ageâthe
more densely cratered a region, the older it is. Hence,
Mars has an ancient hemisphere and a relatively
young hemisphere.
Mars is a small worldâhalf Earthâs diameterâwith
large features. The Valles Marineris canyons, for
example, span more than 4,000 kilometers along
Marsâ equator. Nix Olympica, imaged by Mariner 6
and Mariner 7 from afar and widely interpreted as a
bright crater, turned out to be a shield volcano 25 kilo-
meters tall and 600 kilometers wide at its base.
Renamed Olympus Mons (âMount Olympusâ), it
stands at one edge of the Tharsis Plateau, a continent-
sized tectonic bulge dominating half the planet. Three
other shield volcanoes on the scale of Olympus Mons
form a line across Tharsisâ center.
Most exciting for those interested in Martian life were
signs of water. Mariner 9 charted channels tens of kilo-
meters wide. Some contain streamlined âislandsâ
apparently carved by enormous rushing floods. Many of
the giant channels originate in the southern highlands
and open out onto the smooth northern plains. The
northern plains preserve rampart cratersâalso called
âsploshâ cratersâwhich scientists believe were formed
by asteroid impacts in permafrost. The heat of impact
apparently melted subsurface ice, which flowed out-
ward from the impact as a slurry of red mud, then
refroze.
4
53
Humans to Mars: Fifty Years of Mission Planning, 1950â2000
Chapter 6: Viking and the Resources of Mars
Mariner 9 depleted its nitrogen attitude-control propel-
lant on 27 October 1972, after returning more than
7,200 images to Earth. Controllers quickly lost radio
contact as it tumbled out of control. A week later, on 6
November 1972, mission planners using Mariner 9
images announced five candidate Viking landing sites.
5
Viking 1 left Earth on 20 August 1975 and arrived in
Mars orbit on 19 June 1976. Its twin, Viking 2, left
Earth on 9 September 1975 and arrived at Mars on 7
August 1976. The spacecraft consisted of a nuclear-
powered lander and a solar-powered orbiter. The Viking
1 lander separated from its orbiter and touched down
successfully in eastern Chryse Planitia on 20 July
1976. Viking 2 alighted near the crater Mie in Utopia
Planitia on 3 September 1976.
The first color images from the Viking 1 lander showed
cinnamon-red dirt, gray rocks, and a blue sky. The sky
color turned out to be a processing error based on pre-
conceived notions of what a sky should look like. When
the images were corrected, Marsâ sky turned dusky
pink with wind-borne dust.
6
The Vikings confirmed the old notion that Mars is the
solar system planet most like Earth, but only because
the other planets are even more alien and hostile. A
human dropped unprotected on Marsâ red sands would
gasp painfully in the thin carbon dioxide atmosphere,
lose consciousness in seconds, and perish within two
minutes. Unattenuated solar ultraviolet radiation
would blacken the corpse, for Mars has no ozone layer.
The body would freeze rapidly, then mummify as the
thin, parched atmosphere leeched away its moisture.
By the time the Vikings landed, almost no one believed
any longer that multicellular living things could exist
on Mars. They held out hope, however, for hardy single-
celled bacteria. On 28 July 1976, the Viking 1 lander
scooped dirt from the top few centimeters of Marsâ sur-
face and distributed it among three exobiology detec-
tors and two spectrometers. The instruments returned
identical equivocal readingsâstrong positive responses
that tailed off, weak positive responses that could not
be duplicated in the same sample, and, most puzzling,
an absence of any organic compounds the instruments
were designed to detect.
Viking 1 and Viking 2 each scooped additional samplesâ
even pushing aside a rock to sample underneathâand
repeated the tests several times with similar equivocal
results. Most scientists interpreted the Viking results
as indicative of reactive soil chemistry produced by
ultraviolet radiation interactions with Martian dirt,
not of life. The reactive chemistry probably destroys any
organic molecules.
7
Improved cameras on the Viking orbiters, meanwhile,
added detail to Mariner 9âs Mars map. They imaged
polygonal patterns on the smooth northern plains
resembling those formed by permafrost in Earthâs
Arctic regions. Some cratersâGusev, for exampleâ
looked to be filled in by sediments and had walls
breached by sinuous channels. Perhaps they once held
ice-clad lakes.
The Viking images also revealed hundreds of river-size
branching channelsâcalled âvalley networksââin
addition to the large outflow channels seen in Mariner
9 images. Though some were probably shaped by slow-
ly melting subsurface ice, others appeared too finely
branched to be the result of anything other than sur-
face runoff from rain or melting snow. Ironically, most
of the finely branched channels occurred in the south-
ern hemisphere, the area that reminded people in the
1960s of Earthâs dead Moon. The flyby Mariners might
have glimpsed channels among the Moonlike craters
had their cameras had better resolution.
Low pressure and temperature make free-standing
water impossible on Mars today. The channels in the
oldest part of Mars, the cratered southern highlands,
seem to point to a time long ago when Mars had a
dense, warm atmosphere. Perhaps Mars was clement
enough for a sufficiently long period of time for life to
form and leave fossils.
8
The Viking landers and orbiters were gratifyingly long-
lived. The Viking 1 orbiter functioned until 7 August
1980. Together with the Viking 2 orbiter, it returned
more than 51,500 images, mapping 97 percent of the
surface at 300-meter resolution. Though required to
operate for only 90 days, the Viking 1 lander, the last
survivor of the four vehicles, returned data for more
than six years. The durable robot explorer finally broke
contact with Earth on 13 November 1982.
9
Viking was a tremendous success, but it had been wide-
ly billed as a mission to seek Martian life. The incon-
clusive Viking exobiology results and negative inter-
54
Monographs in Aerospace History
Chapter 6: Viking and the Resources of Mars
pretation placed on them helped dampen public enthu-
siasm for Mars exploration for a decade. Yet Viking
showed Mars to be eminently worth exploring.
Moreover, Viking revealed abundant resources that
might be used to explore it.
Living off the Land
During the period that Mariner 9 and the Vikings
revealed Mars to be a rich destination for explorers,
almost no Mars expedition planning occurred inside
or outside NASA. The Agency was preoccupied with
developing the Space Shuttle, and Mars planners
independent of NASAâwho would make many con-
tributions during the 1980sâwere not yet active in
significant numbers.
Papers on In-Situ Resource Utilization (ISRU) were
among the first signs of re-awakening interest in pilot-
ed Mars mission planning. ISRU is an old concept, dat-
ing on Earth to prehistory. ISRU can be defined as
using the resources of a place to assist in its explo-
rationâthe phrase âliving off the landâ is essentially
synonymous. In the context of space exploration, ISRU
enables spacecraft weight minimization. If a spacecraft
can, for example, collect propellants at its destination,
those propellants need not be transported at great
expense from Earthâs surface. In the 1960s, ISRU was
studied largely in hopes of providing life-support con-
sumables. By the 1980s, the propellant production
potential of ISRU predominated.
NASA first formally considered ISRU in 1962, when it
set up the Working Group on Extraterrestrial
Resources (WGER). The WGER, which met throughout
the 1960s, focused on lunar resources, not Martian.
This was because more data were available on lunar
resource potential, and because lunar resource use
was, in the Apollo era, potentially more relevant to
NASAâs activities.
10
The UMPIRE study (1963-1964) recommended apply-
ing ISRU to establish and maintain a Mars base dur-
ing long conjunction-class surface stays. Doing this
would, of course, demand more data on what resources
were available on Mars. NASA Marshallâs UMPIRE
summary report stated that â[t]his information,
whether it is obtained by unmanned probes or by
manned [flyby or orbiter] reconnaissance missions, would
make such a base possible,â making the â âcost effective-
nessâ of Mars exploration . . . much more reasonable
than [for] the short excursions.â
11
Fifteen years after UMPIRE, the Vikings at last pro-
duced the in-situ data set required for serious consid-
eration of Mars ISRU. The first effort to assess the
potential of Martian propellant production based on
Viking data spun off a 1977-78 NASA JPL study of an
automated Mars sample-return mission proposed as a
follow-on to the Viking program. Louis Friedman
headed the study, which was initially inspired by
President Gerald Fordâs apparently casual mention of
a possible âViking 3â mission soon after the successful
Viking 1 landing.
12
Robert Ash, an Old Dominion
University professor working at JPL, and JPL staffers
William Dowler and Giulio Varsi published their
results in the July-August 1978 issue of the refereed
journal Acta Astronautica.
13
They examined three propellant combinations. Liquid
carbon monoxide and liquid oxygen, they found, were
easy to produce from Martian atmospheric carbon
dioxide, but they rejected this combination because it
produced only 30 percent as much thrust as liquid
hydrogen/liquid oxygen. Electrolysis (splitting) of
Martian water could produce hydrogen/oxygen, but
they rejected this combination because heavy, energy-
hungry cooling systems were necessary to keep the
hydrogen liquid, thus negating the weight-reduction
advantage of in-situ propellant manufacture.
Liquid methane/liquid oxygen constituted a good com-
promise, they found, because it yields 80 percent of
hydrogen/oxygenâs thrust, yet methane remains liquid
at higher temperatures, and thus is easier to store. The
Martian propellant factory would manufacture
methane using a chemical reaction discovered in 1897
by French chemist Paul Sabatier. In the Sabatier re-
action, carbon dioxide is combined with hydrogen in the
presence of a nickel or ruthenium catalyst to produce
water and methane. The manufacture of methane and
oxygen on Mars would begin with electrolysis of
Martian water. The resultant oxygen would be stored
and the hydrogen reacted with carbon dioxide from
Marsâ atmosphere using the Sabatier process. The
methane would be stored and the water electrolyzed to
continue the propellant production process.
Chapter 6: Viking and the Resources of Mars
55
Humans to Mars: Fifty Years of Mission Planning, 1950â2000
56
Monographs in Aerospace History
Chapter 6: Viking and the Resources of Mars
Ash, Dowler, and Varsi estimated that launching a one-
kilogram sample of Martian soil direct to Earth would
need 3.8 metric tons of methane/oxygen, while launch-
ing a piloted ascent vehicle into Mars orbit would need
13.9 metric tons. These are large quantities of propel-
lant, so conjunction-class trajectories with Mars sur-
face stay-times of at least 400 days would be necessary
to provide enough time for propellant manufacture.
Benton Clark, with Martin Marietta (Vikingâs prime
contractor) in Denver, published the first papers
exploring the life-support implications of the Viking
results. His 1978 paper entitled âThe Viking Resultsâ
The Case for Man on Marsâ pointed out that every kilo-
gram of food, water, or oxygen that had to be shipped
from Earth meant that a kilogram of science equip-
ment, shelter structure, or ascent rocket propellant
could not be sent.
14
Clark estimated that supplies for a
10-person, 1,000-day conjunction-class Mars expedition
would weigh 58 metric tons, or about âone hundred
times the mass of the crew-members themselves.â The
expedition could, however, reduce supply weight, there-
by either reducing spacecraft weight or increasing
weight available for other items, by extracting water
from Martian dirt and splitting oxygen from Martian
atmospheric carbon dioxide during its 400-day Mars
surface stay.
Clark wrote that Mars offered many other ISRU possi-
bilities, but that they probably could not be exploited
until a long-term Mars base was established. This was
because they required structures, processing equip-
ment, or quantities of power unlikely to be available to
early expeditions. Crop growth using the âextremely
saltyâ Martian soil, for example, would probably have to
await availability of equipment for âpre-processing . . . to
eliminate toxic components.â
15
The Vikingsâ robotic scoops barely scratched the
Martian surface, yet they found useful materials such
as silicon, calcium, chlorine, iron, and titanium. Clark
pointed out that these could supply a Mars base with
cement, glass, metals, halides, and sulfuric acid.
Carbon from atmospheric carbon dioxide could serve
clever Martians as a foundation for building organic
compounds, the basis of plastics, paper, and elastomers.
Hydrogen peroxide made from water could serve as
powerful fuel for rockets, rovers, and powered equip-
ment such as drills.
During the 1980s, the Mars ISRU concept generated
papers by many authors, as well as initial experimen-
tation.
16
Robert Ash, for example, developed experimen-
tal Mars ISRU hardware at Old Dominion University
with modest funding support from NASA Langley
17
and
from a non-government space advocacy group, The
Planetary Society.
18
That a private organization would
fund such work was significant.
Before ISRU could make a major impact, piloted Mars
mission planning had to awaken more fully from its
decade-long post-Apollo slumber. Post-Apollo Mars
planning occurred initially outside official NASA aus-
pices. This constituted a sea-change in Mars plan-
ningâup to the 1970s, virtually all Mars planning was
government-originated. In the 1980s, as will be seen in
the coming chapters, individuals and organizations
outside the government took on a central, shaping role.
We didnât know all of the people who finally did
speak . . . until they called us! Somehow they
heard about the conference, through the flyers
we sent around and from word of mouth, and
they volunteered. It really was a Mars
Underground! (Christopher McKay, 1981)
1
Columbia
Columbia, the first Space Shuttle, lifted off from Pad
39A at Kennedy Space Center on 12 April 1981, with
Commander John Young and Pilot Robert Crippen on
board for a two-day test flight. Nearly 12 years before,
the Apollo 11 CSM Columbia had left the same pad
atop a Saturn V at the start of the first Moon landing
mission. For Shuttle flights, the twin Complex 39 pads
were trimmed back and heavily modified. Designated
STS-1, it was the first U.S. piloted space flight since the
joint United States-Soviet Apollo-Soyuz mission in July
1975.
At launch, the 2,050-metric-ton Shuttle âstackâ con-
sisted of the delta-winged orbiter Columbia and twin
45.4-meter-long Solid Rocket Boosters (SRBs)
attached to a 47.4-meter-long expendable External
Tank (ET). Columbia measured 37.2 meters long with
a wingspan of 23.8 meters. Seconds before planned
liftoff, the three Space Shuttle Main Engines (SSMEs)
in the orbiterâs tail ignited in rapid sequence, drawing
liquid hydrogen and liquid oxygen propellants from
the ET. Then, at T-0, the two SRBs lit up. Unlike the
Saturn V, which climbed slowly during first-stage
operation, Columbia leapt from the launch pad. Also
unlike the Saturn V engines, the SRBs could not be
turned off once they ignited, making abort impossible
until they exhausted their propellants and separated.
This was not considered a major riskâSRBs, used
since the 1950s, were considered a mature technology.
Two minutes into STS-1, the SRBs separated and fell
into the Atlantic for recovery and reuse. Columbiaâs
SSMEs, the worldâs first reusable large rocket engines,
continued pushing the orbiter and ET toward space.
Eight and one-half minutes after launch, the SSMEs
shut down and the ET separated. Young and Crippen
fired Columbiaâs twin Orbiter Maneuvering System
(OMS) engines to complete orbital insertion while the ET
tumbled and reentered, then opened the long doors cov-
ering Columbiaâs 18.3-meter by 4.6-meter payload bay.
The payload bay was the orbiterâs raison dâĂȘtre.
Maximum payload to low-Earth orbit was about 30
metric tons, though center of gravity and landing
weight constraints restricted this to some degree. The
payload bay could carry satellites for release into orbit
or a European-built pressurized laboratory module
called Spacelab. The Space Shuttle orbiter was also the
only space vehicle that could rendezvous with a satel-
lite and capture it for repair or return to Earthâit
could return about 15 metric tons to Earth in its pay-
load bay. NASA hoped to use the Space Shuttle to
launch components for an Earth-orbiting space station
and other vehicles, such as aerobraking Orbital
Transfer Vehicles (OTVs) based at the station.
On 14 April Young and Crippen fired Columbiaâs OMS
engines for about two minutes to begin reentry. The
STS-1 reentry had almost nothing in common with pre-
vious piloted reentries. Columbiaâs heat shield did not
ablateâthat is, burn awayâto protect it from the fric-
tion heat of reentry. Instead, in the interest of reusabil-
ity, Columbia relied on more than 24,000 individually
milled spun-glass tiles to shield its aluminum skin.
After a pair of close-timed sonic boomsâthey would
become a Space Shuttle trademarkâColumbia glided
to a touchdown on the wide dry lake bed at Edwards
Air Force Base, California. Future landings would
occur on a runway seven kilometers from the Complex
39 Shuttle pads at KSC.
2
NASA heralded the flight as the start of a new era of
routine, inexpensive space access that might spawn
industry off Earth. An ebullient Young told reporters,
âWeâre not really too farâthe human race isnâtâfrom
going to the stars.â
3
The Case for Mars
The Mars buffs who were gathered in Boulder,
Colorado, for the first Case for Mars conference, just
two weeks after the first Shuttle flight, would have set-
tled for NASAâs setting its sights on Marsânever mind
the stars. Fueled by the Viking discoveries, would-be
Mars explorers dared look beyond the Space Shuttle.
They hoped that Mars ship propellants and components
might soon be manifested as Shuttle payloads. They
also saw in the Shuttle and in the Space Station
Program (expected soon to follow) sources of hardware
57
Humans to Mars: Fifty Years of Mission Planning, 1950â2000
Chapter 7: The Case for Mars
for Mars ship parts, much as planners in the 1960s envi-
sioned using Apollo hardware for piloted Mars flybys.
The 1981 Case for Mars conference provided the first
public forum for Mars planning since the 1960s. The
conference crystallized around an informal seminar
based on NASAâs 1976 study The Habitability of Mars,
organized by Christopher McKay, a University of
Colorado at Boulder astro-geophysics Ph.D. candidate.
The seminar brought together Mars enthusiasts from
Boulder and around the country.
The âMars
Underground,â as they light-heartedly called them-
selves, decided in the spring of 1980 that the time was
ripe for a conference on Mars exploration.
4
The Case for Mars conference drew its name from the
title of Benton Clarkâs 1978 Mars ISRU paper (see
chapter 6). Clark took part in the conference, along
with about 300 other engineers, scientists, and enthu-
siasts.
5
It was the largest gathering of would-be Mars
explorers since the 1963 Symposium on the Manned
Exploration of Mars.
The conference was in part a brain-storming sessionâ
an opportunity to take stock of ideas on how to explore
Mars. Among the concepts presented was S. Fred
Singerâs âPH-D Proposal,â which drew upon Shuttle-
related technology expected to exist in 1990.
6
Singerâs
scenario had staying powerâhe was still writing about
it in the spring of 2000.
7
Singerâs $10-billion expedition would use Deimos, Marsâ
outer moon, as a base of operations for exploring the
Martian system. It was similar to the 1960s piloted
flyby and orbiter missions in how it minimized space-
craft weight. None of the six to eight astronauts would
land on Mars, though a sample-return lander would
bring up a âgrab sampleâ from the planet and two astro-
nauts would visit Phobos, Marsâ inner moon. The astro-
nauts would remote-control between 10 and 20 Mars
surface rovers during their two-to-six-month stay in the
Martian system. At Deimosâ orbital distance, round-trip
radio travel time would be only one-fifth of a second.
Two astronauts would be âmedical scientistsâ who
would study human reactions to weightlessness, radia-
tion, and isolation throughout the expedition. They
would minimize risk to the crew from these long-
duration space flight hazards by continually monitoring
their health; data they gathered would also minimize risk
for future Mars landing expeditions.
Singerâs expedition would rely on solar-electric
thrusters, using electricity from a large solar array to
ionize and electrostatically expel argon gas. As
described in chapter 2, electric propulsion thrusters
produce constant low-thrust acceleration while using
very little propellant. Singer assumed that the solar
array would be available in high-Earth orbit in 1990 as
part of a pre-existing Shuttle-launched cislunar infra-
structure. The cost of the solar array was thus not
included in Singerâs expedition cost estimate.
At the start of the PH-D Proposal expedition, the
unpiloted solar-electric propulsion system would spiral
out from Earth, slowly gaining speed. Several weeks
later, as it was about to escape Earth orbit, the piloted
Phobos-Deimos craft would catch up, using chemical
rockets, and dock. This technique minimized risk to
crew by reducing the amount of time they had to spend
in weightlessness and by speeding them through the
Van Allen Radiation Belts. The solar-electric propulsion
system would accelerate the spacecraft until expedition
mid-point; then its thrusters would be turned to point in
the direction of travel. The spacecraft would then decel-
erate until it was captured into orbit by Marsâ gravity.
The 1990-91 target launch date would allow Singerâs
expedition to take advantage of a Venus flyby opportu-
nity to gain speed and change course without using
propellant. Total expedition duration would be âsome-
thing less than two years.â Electric propulsion plus
Venus flyby plus postponing the piloted Mars landing
until a later expedition would reduce spacecraft weight
at Earth-orbit departure to about 300 tons.
The Planetary Society
In 1983, The Planetary Society, a non-profit space
advocacy organization with about 100,000 members,
commissioned the most detailed piloted Mars mission
study since 1971. The organization did this because,
as Society president Carl Sagan and executive direc-
tor Louis Friedman wrote in their foreword to the
study report, âsince Apollo, there have been, in the
United States at least, almost no serious studies of
manned (or womanned) voyages to other worlds,
despite the fact that enormous technological advances
58
Monographs in Aerospace History
Chapter 7: The Case for Mars
have been made since those early lunar landings.â
8
Writing in the Societyâs member magazine, The
Planetary Report, Friedman explained that âwe fund-
ed [the study] because it is important to have solid
technical evidence to back us in our advocacy of new
goals . . . .â
9
The nine-month study, âa labor of loveâ
performed at a âbargain basement priceâ by Science
Applications International Corporation (SAIC), was
completed in September 1984.
10
SAICâs Mars mission design resembled MSCâs 1963
Flyby-Rendezvous mode. Eighteen Space Shuttle
launches would deliver more than 160 metric tons of
spacecraft components to Earth orbit. The four-person
crew would travel to Mars in a 121-metric-ton
Outbound Vehicle consisting of four âsub-vehicles.â
These were the 38-metric-ton Interplanetary Vehicle,
the 19-metric-ton Mars Orbiter, the 54-metric-ton Mars
Lander, and the 10-metric-ton Mars Departure Vehicle.
The Interplanetary Vehicle, which would provide one-
quarter of Earthâs gravity by spinning three times each
minute, would include pressurized crew modules based
on Spacelab modules. The Mars Orbiter, the Mars
Departure Vehicle, and the conical, two-stage Mars
Lander were together designated the Mars Exploration
Vehicle (MEV). The MEV would include a 54-meter-
diameter aerobrake. The crew would return from Mars
in the 43-metric-ton Earth Return Vehicle (ERV),
which resembled the Interplanetary Vehicle except in
that it would include a conical 4.4-metric-ton Earth-
return capsule nested in a 13-meter-diameter aero-
brake. Of these vehicles, only the MEV would have to
slow down and enter Mars orbit. This, plus extensive
use of aerobraking, would reduce the amount of propel-
lant required to carry out SAICâs Mars expedition,
which in turn would reduce spacecraft weight.
The unpiloted ERV would depart Earth orbit on 5 June
2003, using three large OTVs stacked together, each
carrying over 27 metric tons of propellants. The SAIC
team assumed that reusable space-based OTVs would
be available in Earth orbit as part of NASAâs Space
Station Program. The expense of developing, launching,
and operating the OTVs was thus not counted in the
cost of the expedition. OTV 1 would fire its engines at
perigee, increasing its apogee distance, then separate.
OTV 2 would repeat this procedure. OTV 3âs perigee
burn would place the ERV on course for Mars. This
series of maneuvers would require about six hours.
The crew would depart Earth in the Outbound Vehicle
ten days later, on 15 June 2003. Because it was nearly
three times heavier than the ERV, the Outbound
Vehicle would need perigee burns by seven OTVs over
about two days to achieve a Mars-bound trajectory.
On 24 December 2003, the crew would near Mars in
the Outbound Vehicle, board and undock the MEV, and
aerobrake into Mars orbit.
The
abandoned
Interplanetary Vehicle would fly past Mars into solar
orbit. Three of the four crew would enter the Mars
Lander and descend to the surface, which they would
explore using a pressurized rover. On 23 January
2004, after a month on Mars, the surface crew would
lift off in the Mars Lander ascent stage with 400 kilo-
grams of rock samples to rejoin their colleague aboard
the Mars Orbiter.
The ERV, meanwhile, would approach Mars on a flyby
trajectory. The crew would board the Mars Departure
Vehicle, abandon the Mars Lander ascent stage and
Mars Orbiter, and leave Mars orbit in pursuit of the
ERV. Rendezvous and docking would occur while the
ERV was outbound from Mars. Friedman noted that
â[b]ecause the orbit doesnât close around Mars, the crew
has only a chance at one precise time, to rendezvous
with the return vehicle. Although this is risky, SAIC
analysis found it acceptable compared to other mission
risks. (However, some of us at The Planetary Society
wonder if the crew will feel the same way!)â
11
Eighteen months later, on 5 June 2006, the crew
would board the Earth-return capsule and separate
from the ERV. They would aerobrake in Earthâs
atmosphere while the abandoned ERV flew past
Earth into solar orbit.
The SAIC team estimated the cost of their Mars expe-
dition at $38.5 billion in 1984 dollars, of which $14.3
billion would be spent on Mars spacecraft hardware,
$2 billion would pay for Shuttle launches, and $18.5
billion would be spent on operations. Friedman point-
ed out that, over a decade, this cost averaged about $4
billion annually, or about 60 percent of NASAâs
approximately $7-billion FY 1984 budget.
12
59
Humans to Mars: Fifty Years of Mission Planning, 1950â2000
Chapter 7: The Case for Mars
Space Station
Traditionally, space stations have been envisioned as
having multiple functions, not least of which was as an
assembly and servicing baseâa spaceportâfor space-
craft, including those bound for Mars. In 1978, as Space
Shuttle development moved into its final stages,
NASAâs Johnson Space Center (JSC) (as MSC was
renamed in 1973) began planning a Shuttle-launched
modular space station called the Space Operations
Center (SOC). A space shipyard, the SOC was the most
important station concept in the years 1978 through
1982âthe period immediately before gaining approval
for a station became a realistic goal for NASA.
13
An internal NASA presentation in May 1981âone
month after STS-1âdescribed the SOC as the cen-
tral element of a âspace operations systemâ that
would include the Space Shuttle, OTVs for moving
objects assembled at the SOC to orbits beyond the
Shuttleâs altitude limit, and Manned OTVs for
transporting astronauts on satellite service calls.
14
A
JSC press release in early 1982 referred to the SOC
as a âspace base and marshaling yard for large and
complex payloadsâ providing âgarage space for
reusable cryogenic stages.â
15
After his first year in office, during which NASA took
deep cuts, President Ronald Reagan came to see the
political benefits of being identified with a successful
space program. On 4 July 1982, Columbia returned
from space at the end of mission STS-4. Reagan was on
hand amid fluttering American flags to declare the
Shuttle operational. He spoke of establishing a more
permanent presence in space, but withheld a clear
mandate to build a space station until his 25 January
1984 State of the Union address. When he did, he
emphasized its laboratory function:
We can follow our dreams to distant stars, liv-
ing and working in space for peaceful economic
and scientific gain. Tonight I am directing
NASA to develop a permanently manned Space
Station and to do it within a decade. The Space
Station would permit quantum leaps in our
research in science, communications, in metals
and in life-saving medicines which can only be
manufactured in space . . . .
16
The lab function was emphasized partly to keep the
Stationâs estimated cost as close to $8 billion as possi-
ble.
17
As we have seen, Mars planners early in the
1980s assumed that OTVs and other Earth-orbit infra-
structure applicable to Mars exploration would soon
become available. With the spaceport role de-empha-
sized and the lab role moved to the fore, the justifica-
tion for OTVs was largely removed, and the ability to
assemble other Earth-orbit infrastructure, such as
Singerâs solar array, was made forfeit. Assembling the
Space Station itself would provide some experience
with application to Mars ship assembly. However, it
would provide little experience with handling tankage
and propellants in space, both crucial to building a
Mars ship.
Soviets to Mars
In the early 1980s, such NASA advanced planning as
existed focused more on the Moon than on Mars. The
revival in NASA Mars interest owes much to geologist
and Apollo 17 Moonwalker Harrison Schmitt, and to
the Agencyâs lunar base studies, which had never
receded to the same degree as its Mars studies.
Schmitt was concerned about an on-going Soviet space
buildup, which saw long stays by cosmonauts aboard
Salyut space stations and development of a Soviet
shuttle and heavy-lift rocket, as well as plans for ambi-
tious robotic Mars missions.
18
Schmitt also concentrat-
ed on Mars because he had asked children, the future
space explorers, about returning to the Moon and
found that they were not interested because people
had already been there.
19
Schmitt had attempted to promote Mars exploration in
the late 1970s while serving as Republican U.S.
Senator from New Mexico. Following Vikingâs success,
he had put forward a bill calling for the U.S. to develop
the capability to establish a settlement on Mars by
2010. His âChronicles Planâ excited momentary inter-
est in President Jimmy Carterâs White House, inducing
NASA Administrator Robert Frosch to activate a small
NASA study team. The teamâs July 1978 workshop at
Wallops Island, Virginia, produced nothing new. In fact,
the consensus was that âpast work [from the 1960s]
should not be updated unless serious consideration is
being given to conducting a manned Mars mission prior
to the year 2000.â
20
In short, NASA was too busy work-
ing on the Space Shuttle in 1978 to think about Mars.
60
Monographs in Aerospace History
Chapter 7: The Case for Mars
61
Humans to Mars: Fifty Years of Mission Planning, 1950â2000
Schmitt renewed his Mars efforts in 1983 by contacting
Paul Keaton of LANL during a meeting held in the run-
up to the 1984 Lunar Bases and Space Activities of the
21st Century conference, held at the National Academy
of Sciences in Washington, DC.
21
As seen in Chapter 5,
LANL was involved in space flight before NASA was
created through its work on nuclear rockets. At the
lunar base conference, Schmitt presented a paper on
his âMars 2000 Millennium Project,â which he hoped
would âmobilize the energies and imaginations of
young people who are already looking beyond Earth
orbit and the [M]oon.â
22
He also made contact with
NASA engineers and scientists interested in exploring
Mars as well as the Moon.
23
Schmitt then pressed for a study to give the President
the option to send humans to Mars should he desire to
respond to the Soviet buildup. LANL partnered with
NASA to conduct the Manned Mars Mission (MMM)
study during 1984 and 1985. The effort culminated in
the joint NASA-LANL MMM workshop at NASA
Marshall (10-14 June 1985).
24
The workshop published
three volumes of proceedings in 1986.
25
Especially noteworthy, given Schmittâs primary ration-
ale for the MMM workshop, was a JSC plan for a pilot-
ed Mars flyby based on technology expected to exist in
the 1990s as part of the Space Station Program. This
aimed at countering a possible Soviet piloted Mars
flyby mission.
In April 1985, at Schmittâs request, the CIA prepared
an analysis of possible Soviet space moves. The analy-
sis cited â[p]ublic comments in 1982 by the Soviet
S[cience] & T[echnology] Attaché assigned to
Washington and in 1984 by the President of the Soviet
Academy of Science,â which suggested that âthe
Soviets have confidence in their ability to conduct such
a mission.â The CIA then predicted that â . . . they will
choose a one-year flyby as their first step.â
26
The analysis cited current and future indicators point-
ing to Soviet piloted Mars exploration. These included
continuing work on a heavy-lift rocket âcapable of
placing into low-earth orbit about five times the
payload of the present largest Soviet space launch
vehicle, thereby significantly reducing the number
of launch vehicles required.â
27
The âstrongest current
indicator,â however, was âthe long-duration stays in
space by cosmonautsâ aboard Salyut space stations.
Potential future indicators included âa cosmonaut stay
in low-earth orbit of one year duration . . . [and] space
tests of a nuclear propulsion system . . . .â
28
The CIA
guessed that the first Soviet Mars flyby might occur as
early as 1992, in time for the 500th anniversary of
Columbusâs arrival in the Americas.
29
The JSC flyby plan for countering this possible Soviet
move was prepared by Barney Roberts, who performed
lunar base studies in the JSC Engineering Directorate.
30
Robertsâ year-long Mars flyby mission would begin with
orbital assembly at the Space Station. Shuttles would
deliver two expendable strap-on propellant tanks and
an 18-ton Mission Module to the Station. The latter
would dock with a 6-ton Command Module (not to be
confused with the Apollo CM) and two 5.75-ton OTVs
assumed to be in space already as part of the Space
Station Program. Shuttle-derived heavy-lift rockets
would then deliver 221 tons of liquid hydrogen/liquid
oxygen propellants. The propellants would be loaded
into the strap-on and OTV tanks just prior to departure
for Mars. Spacecraft weight at Earth-orbit departure
would come to 358 tons.
Chapter 7: The Case for Mars
Figure 18âIn 1985, NASAâs Johnson Space Center
responded to suspected Soviet Mars plans by proposing a
U.S. Mars flyby using Space Station and lunar base hard-
ware then planned for the 1990s. Here the flyby spacecraft
orbits Earth before setting out for Mars. (âConcept for a
Manned Mars Flyby,â Barney Roberts, Manned Mars
Missions: Working Group Papers, NASA M002, NASA/Los
Alamos National Laboratories, Huntsville, Alabama/Los
Alamos, New Mexico, June 1986, Vol. 1, p. 210.)
62
Monographs in Aerospace History
At the proper time, the OTV engines would ignite and
burn for about one hour to put the flyby craft on course
for Mars. This would empty the strap-on tanks, but
Roberts advised retaining them to provide additional
meteoroid and radiation shielding for the crew mod-
ules. After a six-month Earth-Mars transfer, the flyby
spacecraft would spend two and one-half hours within
about 20,000 miles of Mars. Closest approach would
occur 160 nautical miles above the Martian surface
with the flyby craft moving at 5 miles per second.
As Earth grew from a bright star to a distant disk, the
astronauts would discard the strap-on tanks, then
undock one OTV and redock it to the Command Module.
They would enter the Command Module and discard
the Mission Module and the second OTV. The OTV/
Command Module combination would slow to a manage-
able reentry speed using the OTVâs engines, aerobrake to
Earth-orbital speed, then dock at the Space Station.
Roberts found (as had planners in the 1960s) that
Earth return was the most problematical phase of the
flyby mission because the OTV would hit Earthâs
atmosphere at 55,000 feet per second, producing fric-
tion heating beyond the planned limits of the OTV heat
shields. In addition, the crew would experience âexorbi-
tantâ deceleration levels after spending a year in
weightlessness.
In the 1960s, planners proposed a Venus flyby to reduce
reentry speed without using propellant, but Roberts
did not mention this possibility. He proposed instead to
slow the OTV and Command Module to 35,000 feet per
second using the formerâs engines. Adding this burn
would nearly double spacecraft weight at Earth-orbit
departure. Roberts calculated that, assuming the Space
Shuttle-derived heavy-lift rocket could deliver cargo to
Earth orbit at a cost of $500 per pound, Earth-braking
propellant would add $250 million to mission costs.
31
Interplanetary Infrastructure
Some Mars planners envisioned the NASA Space
Station in low-Earth orbit as merely the first in a series
of stations in logical places serving as Mars trans-
portation infrastructure, much like trails, canals, rail-
Chapter 7: The Case for Mars
Figure 19âDuring return to Earth the flyby spacecraft
discards empty propellant tanks, revealing cylindrical
Command and Mission Modules between twin almond-
shaped Orbital Transfer Vehicles. (âConcept for a Manned
Mars Flyby,â Barney Roberts, Manned Mars Missions:
Working Group Papers, NASA M002, NASA/Los Alamos
National Laboratories, Huntsville, Alabama/Los Alamos,
New Mexico, June 1986, Vol. 1, p. 210.)
Figure 20âThe flyby crew prepares to aerobrake in Earthâs
atmosphere. As Earth grows from a bright star to a disk, they
undock the Command Module and one Orbital Transfer
Vehicle, abandoning the second Orbital Transfer Vehicle and
their home for the previous year, the Mission Module.
(âConcept for a Manned Mars Flyby,â Barney Roberts,
Manned Mars Missions: Working Group Papers, NASA
M002, NASA/Los Alamos National Laboratories, Huntsville,
Alabama/Los Alamos, New Mexico, June 1986, Vol. 1, p. 213.)
ways, and coaling stations formed transportation infra-
structure in bygone days. They looked ahead to solar-
orbiting space stations, known as cyclers, traveling a
regular path between Earth and Mars, and to space-
ports at the Lagrange gravitational equilibrium points.
Apollo 11 Lunar Module Pilot Buzz Aldrin, the second
man on the Moon, described cyclers in a popular-audience
article in Air & Space Smithsonian magazine in 1989:
Like an oceanliner on a regular trade route, the
Cycler would glide perpetually along its beauti-
fully predictable orbit, arriving and departing
with clock-like regularity. By plying the solar
systemâs gravitational âtrade windsâ it will carry
mankind on the next great age of exploration
. . . . For roughly the same cost as getting
humans safely to Mars via conventional expend-
able rocketry (because the problems to be solved
would be largely the same), the Cycler system
would provide a reusable infrastructure for trav-
el between Earth and Mars far into the future.
32
In the 1960s, Massachusetts Institute of Technology pro-
fessor Walter Hollister and others studied âperiodicâ
orbits related to Crocco flyby orbits but indefinitely
repeating. A space station in such an orbit would cycle
âforeverâ between Earth and the target planet. In
January 1971, Hollister and his student, Charles Rall,
described an Earth-Mars transport system in which at
least four cycling periodic-orbit stations would operate
simultaneously, permitting opportunities every 26
months for 6-month transfers between Earth and Mars.
33
As the large periodic-orbit station flew past Earth or
Mars, small ârendezvous shuttle vehiclesâ would race
out to meet it and drop off crews and supplies for the
interplanetary transfer. After several Mars voyages,
the cycler approach would yield a dramatic reduction in
spacecraft mass over the MOR mission mode because
the cycler would only need to burn propellants to leave
Earth orbit once; after that, only the small shuttles
would need to burn propellants to speed up and slow
down at Earth and Mars.
The Case for Mars II conference (10-14 July 1984)
included a workshop that planned âa permanent Mars
research base using year 2000 technologyâ as a âpre-
cursor to eventual colonization.â The Case for Mars II
workshop took advantage of the long-term weight-
minimization inherent in cyclers and Mars ISRU. The
Boulder Center for Science and Policy published a JPL-
funded report on the workshop results in April 1986.
34
The Case for Mars had begun to gather steam.
Participants in the second conference included
Harrison Schmitt with a paper on his Mars 2000 proj-
ect, Benton Clark, and Christopher McKay, who had
earned his Ph.D. and gone to work at NASA Ames.
Former NASA Administrator Tom Paine presented a
timeline of Mars exploration spanning 1985 to 2085. It
predicted, among other things, a lunar population in
the thousands in the 2025-2035 decade and a Martian
population of 50,000 in the 2055-2065 decade.
35
Barney
Roberts, Michael Duke, and lunar scientist Wendell
Mendell presented a paper called âLunar Base:
A
Stepping Stone to Mars,â
36
while NASA Space Station
manager Humboldt Mandell presented a paper called
âSpace Station: The First Step.â
37
In the Case for Mars II plan, the cyclerâs Earth-Mars leg
lasted six months, followed by a Mars-Earth leg lasting
20 to 30 months. Each crew would spend two years on
Mars, and new crews would leave Earth every two years.
The first crew would leave Earth in 2007 and return in
2012; the second crew would depart in 2009 and return
in 2014; and so on. This schedule would require at least
two cyclers. As Hollister and Rall proposed, small Crew
Shuttle vehicles would transfer crews to and from the
passing cycler. The Crew Shuttles were envisioned as
two-stage biconic vehicles designed for aerobraking at
Earth and Mars. Their proposed shape was derived
from ballistic missile warhead research.
A heavy-lift rocket capable of launching at least 75
metric tons, possibly based on Shuttle hardware, would
place cycler components, some based on Shuttle and
Space Station hardware, into Earth orbit for assembly.
The 1984 Case for Mars plan called for cycler assembly
at the low-Earth orbit Space Station; in a subsequent
version, a dedicated assembly facility was proposed.
The first Mars expedition would require 24 heavy-lift
rocket launches and 20 Shuttle launches.
ISRU would supply the Case for Mars II base with
many consumables, including propellant. âMars is
abundantly endowed with all the resources necessary
to sustain life,â the report stated, adding that âpropel-
lant production on the surface of Mars is critical to
reducing the cost of the programâ because it âreduces
the Earth launch weight by almost an order of magni-
63
Humans to Mars: Fifty Years of Mission Planning, 1950â2000
Chapter 7: The Case for Mars
64
Monographs in Aerospace History
tude.â
38
Each Crew Shuttle would require 150 tons of
Mars ISRU-manufactured carbon monoxide/oxygen
propellant to catch up with the passing Earth-bound
cycler. The Case for Mars II workshop proposed that an
automated probe should test ISRU propellant produc-
tion on Mars before the Mars base program began.
Lagrangia
Like the cycler concepts, the notion of siting infrastruc-
ture at the Lagrange points dates to the 1960s. Its theo-
retical roots, however, date to 1772. In that year, French
mathematician Joseph Lagrange noted that gravitation-
al equilibrium points exist in isolated two-body systems.
Lagrange points exist in spaceâfor example, in the
two-body Earth-Moon system. In theory, an object
placed at one of these points will remain as if nesting
in a little cup of space-time. In practice, Lagrange
points in space are unstable or quasi-stable because
planets and moons do not exist as isolated two-body
systems. In the case of the Earth-Moon system, the
Sunâs gravitational pull introduces instability.
Objects placed at the Earth-Moon Lagrange points
thus tend to move in âhalo orbitsâ around the
Lagrange point and require modest station keeping
to avoid eventual ejection.
Robert Farquhar, an engineer at NASAâs Goddard
Space Flight Center in Greenbelt, Maryland, first
wrote about using the Lagrange equilibrium points of
the Earth-Moon system in the late 1960s.
39
For the
NASA MMM workshop in June 1985, Farquhar teamed
up with David Dunham of Computer Sciences
Corporation to propose using Lagrange points as âstep-
ping stonesâ for Mars exploration.
40
Farquhar and Dunham envisioned a large, reusable
Interplanetary Shuttle Vehicle (ISV) in halo orbit about
the quasi-stable Earth-Sun Lagrange 1 point, 1.5 mil-
lion kilometers in toward the Sun. A Mars transport
spacecraft parked there would be gravitationally bound
to Earth much more weakly than if parked in low-Earth
orbit. A mere propulsive burp would suffice to nudge the
ISV out of halo orbit; then gravity-assist swingbys of the
Moon and Earth would place it on course for Mars with
little additional propellant expenditure. This meant, of
course, that the amount of propellant that would need
to be launched from Earth was minimized. To save even
more propellant, the ISV might park at the Mars-Sun
Lagrange 1 point, about 1 million kilometers Sunward
from Mars, and send the crew to the Martian surface
using small shuttle vehicles.
Farquhar and Dunham pointed out that an automat-
ed spacecraft had already left Earth-Sun Lagrange 1
on an interplanetary trajectory. The International
Sun-Earth Explorer-3 spacecraft had entered Earth-
Sun Lagrange 1 halo orbit on 20 November 1978.
After completing its primary mission it was maneu-
vered during 1984 through a series of Earth and
Moon swingbys to place it on course for Comet
Giacobinni-Zinner. Farquhar supervised the effort.
The maneuvers consumed less than 75 kilograms of
propellant. Renamed the International Comet
Explorer, the spacecraft successfully flew past
Giacobinni-Zinner, 73 million kilometers from Earth,
on 11 September 1985.
Paul Keaton elaborated on Farquhar and Dunhamâs
MMM paper in a âtutorialâ paper published in August
1985. He wrote that â[a]n evolutionary manned space
program will put outposts along routes with economic,
scientific, and political importanceâ to serve as ââfilling
stationsâ for [making and] storing rocket fuelâ and
âtransportation depots for connecting with flights to
other destinations.â
41
The first outpost would, of course, be NASAâs planned
Space Station in low-Earth orbit, where Earthâs mag-
netic field would help protect travelers from galactic
cosmic rays and solar flare radiation, and medical
researchers would learn about the effects of long-term
weightlessness on the human body. Keaton then looked
beyond Earth orbit for the next outpost site. He pro-
posed placing it in halo orbit around the Earth-Moon
Lagrange 2 point, 64,500 kilometers behind the Moon,
or at Farquharâs Earth-Sun Lagrange 1 site. He wrote,
[f]or the settlement of space, a Lagrange equi-
librium point between the Sun and Earth has
the nearly ideal physical characteristics of a
transportation depot . . . . Lagrange point halo
orbits are the present standard by which any
alternative concept for a transportation depot
must be gauged.
42
Cyclers and Lagrange point spaceportsâinfrastruc-
ture spanning worldsâimply large-scale permanent
Chapter 7: The Case for Mars
65
Humans to Mars: Fifty Years of Mission Planning, 1950â2000
Chapter 7: The Case for Mars
space operations and long-term commitment to build-
ing space civilization. Such grandiose visions are not
widely shared outside of a subset of the small com-
munity of would-be Mars explorers, as will be seen in
the next chapter.
Mars is the world next door, the nearest planet
on which human explorers could safely land.
Although it is sometimes as warm as a New
England October, Mars is a chilly place, so cold
that some of its thin carbon dioxide atmosphere
freezes out at the winter pole. There are pink
skies, fields of boulders, sand dunes, vast
extinct volcanoes that dwarf anything on
Earth, a great canyon that would cross most of
the United States, sandstorms that sometimes
reach half the speed of sound . . . hundreds of
ancient river valleys . . . and many other mys-
teries. (The Mars Declaration, 1987)
1
National Commission on Space
Late 1984, when the Space Shuttle was operational
and Space Station development was underway, seemed
an auspicious time to begin charting a course for NASA
to follow after Space Station completion in the early
1990s. Congress mandated that President Reagan cre-
ate an independent commission to sort through the
possibilities and provide recommendations. The
National Commission on Space (NCOS) was launched
officially on 29 March 1985 with the goal of blueprint-
ing the next 20 years of the civilian space program. The
NCOS was to present results to the White House and
Congress following a one-year study.
Reagan tapped Tom Paine, NASA Administrator
from 1968 to 1970, to head the NCOS. Fourteen com-
missioners joined Paine. They included such lumi-
naries as Neil Armstrong, the first human to walk on
the Moon; Chuck Yeager, the first human to break
the sound barrier;
former United Nations
Ambassador Jeane Kirkpatrick; Space Shuttle astro-
naut Kathy Sullivan; and retired Air Force General
Bernard Schriever. Laurel Wilkening, a planetary
scientist and Vice Provost of the University of
Arizona, was Vice Chair.
Non-voting NCOS members included representatives
from both parties of Congress and the Departments of
State, Commerce, Agriculture, and Transportation, as
well as the National Science Foundation and the White
House Office of Science and Technology Policy. In addi-
tion to the inputs provided by its members, the NCOS
held public forums and solicited written contributions
from academe, business, and the general public.
The result was Pioneering the Space Frontier, a glossy
report billed as âan exciting vision of our next fifty
years in space.â
2
It was the first in a series of high-pro-
file space reports produced in the Reagan/Bush years.
Paineâs attitude had not changed much since his time
as NASA Administrator. He still saw it as his job to
challenge Americans to take on the solar system. The
NCOS reportâs expansive vision bore Paineâs unmistak-
able stamp; in fact, it bore a resemblance to Paineâs
timeline from the Case for Mars II. Paine looked to an
expanding 21st-century economy with âfree societies
on new worldsâ and âAmerican leadership on the new
frontier.â
Events caught up with the NCOS exercise, however. On
the chilly Florida morning of 28 January 1986, with
much of the Commissionâs work complete, Space
Shuttle Challenger exploded 73 seconds into mission
STS-51L, killing seven astronauts and grounding the
remaining three Shuttle orbiters. The immediate cause
of the accident was failure of a seal in one of the
Shuttleâs twin SRBs.
The Challenger accident threw the giddy optimism of
Paineâs NCOS report into sharp relief. It was a wake-up
call. The Space Shuttle would not, could not, provide the
kind of low-cost, routine space access envisioned during
the 1970s. âThe myth of an economic Shuttleâ was laid
bare.
3
The basic tool for establishing space infrastruc-
ture was found wanting, forcing many of the infrastruc-
ture elements envisioned by Mars planners in the early
1980s into some indefinite post-Shuttle future.
The accident contributed to NASAâs decision to redesign
the Space Station in mid-1986. After more than two years
of studies, NASA had unveiled its station design in early
1986. Called the Dual Keel, it was primarily a space lab-
oratory, but included a large rectangular truss which
might eventually hold hangars, assembly equipment, and
a propellant depot for Moon and Mars spacecraft. The
rectangular truss was, however, adopted primarily to pro-
vide attachment points for anticipated user payloads,
with space-facing payloads on the top and Earth-facing
payloads on the bottom.
4
Following Challenger, the Dual Keel design came to be
seen as too ambitious. The rectangular truss was
deferred to a future Phase II of station assembly. Phase
I would consist of a single straight truss holding solar
67
Humans to Mars: Fifty Years of Mission Planning, 1950â2000
Chapter 8: Challengers
arrays and a cluster of pressurized modules. Designers
sought, however, to include software âscarsâ and hard-
ware âhooksâ in the Phase I design to permit eventual
expansion to the full Dual Keel configuration.
5
From the Mars explorersâ point of view, the accident
demonstrated that the Space Shuttle could not be used
to launch Mars ships. It had been felt by many before
Challenger that the Shuttle would have to be supple-
mented by a heavy-lift rocket if piloted flight beyond
low-Earth orbit was to be a credible NASA goal, but it
became patently obvious to most everyone on that cold
day in January 1986.
Paineâs report was crammed full of new vehicles and
interplanetary infrastructure based largely on SAIC
and Eagle Engineering studies. The NCOS called for
new cargo and passenger launch vehicles to replace the
Space Shuttle by 1999 and 2000, respectively. These
were components of a âHighway to Spaceâ that would
include the initial Earth-orbital Space Station (1992), a
space-based OTV (1998), and an initial Earth-orbital
spaceport (1998). This segued into a âBridge Between
Worldsâ that would include a single-stage-to-orbit
space plane, a Moon base with facilities for mining
lunar oxygen, cyclers and Lagrange point stations,
nuclear-electric space freighters, and, by 2026, a Mars
base resembling the one put forward at the Case for
Mars II workshop (1984).
The NCOS program would cost about $700 billion
between 1995 and 2020. This cost would, Paine wrote,
be paid through increases in NASA funding keeping
pace with projected increases in U.S. GNP of 2.4 per-
cent per year. NASA funding in 1986 was about $10 bil-
lion, or less than 1 percent of GNP. According to the
report, if NASA funding remained near 1 percent of
GNP, it would increase to $20 billion in 2000 and to $35
billion in 2020. For the near-term, the report urged that
the new technology development share of NASAâs budg-
et be raised from 2 percent to 6 percent.
The NCOS turned over its report to the Reagan White
House in March 1986, two months after the Challenger
accident. Paine went public with the report even before
presenting it to the White House by giving a draft to
Aviation Week & Space Technology
magazine.
6
Unusually, the report was also published as a trade
paperback and sold in bookshops.
Paine presented the NCOS report formally to President
Reagan and the Senate and House Space Committees
on 22 July 1986. It urged the White House to direct the
NASA Administrator to respond by 31 December 1986
with general long-range and specific short-range imple-
mentation plans. Paine summed up the NCOS report
the next day at the NASA Mars Conference, underway
at the National Academy of Sciences to commemorate
the tenth anniversary of Viking 1âs landing. He told the
assembled scientists and engineers that Reagan had
assured him that the Commissionâs recommendations
would be accepted.
7
The reportâs conclusion assumedâcorrectlyâthat
Paineâs vision would be seen as grandiose, and took
pains to defend it. As he had done in the 1969 Space
Task Group report, Paine described the technological
progress made in the past in an effort to demonstrate
the progress that could be made in coming decades.
Is our expansive view of Americaâs future
realistic? Are the technical advances we
project achievable? Will people accept the
risks and discomforts to work on other
worlds? We believe that the answer to all
three questions is âYes!â Few Americans in
the early days of the Air Age ever expected to
fly the Atlantic. . . yet nearly 75,000 people
now fly the Atlantic daily . . . . It is equally
difficult for Americans this early in the
Space Age to visualize the 21st-century tech-
nologies that will enable the average citizen
to soar into orbit at low cost, to fly to new
worlds beyond Earth, and to work and live on
the space frontier in closed-ecology bios-
pheres using robotically-processed local
resources . . . . We should . . . emphasize that:
The Commission is not prophesying; it is
describing what the United States can make
happen through vigorous leadership in pio-
neering the space frontier.
8
The NCOS plan was not so much a plan for guiding
NASAâs future as an evocation of the pioneering spirit
which Paine felt was flagging in 20th-century
Americans. The romantic attraction to pioneering has
in fact always been a rare thing. Those afflicted by it
frequently feel great zeal, which blinds them to the fact
that they are raritiesâthat others, while frequently
68
Monographs in Aerospace History
Chapter 8: Challengers
69
Humans to Mars: Fifty Years of Mission Planning, 1950â2000
sympathetic to their vision, do not place as high a pri-
ority as they do upon making it real.
The NCOS report was not well received, primarily
because the Challenger accident had made clear that
NASA was in no position to tackle such an expansive, all-
encompassing plan. But it was also seen as too general,
with too many proposals. In late August 1986, former
Presidential Science Advisor George Keyworth, who
had been a non-voting NCOS member, said the report
had forfeited impact by putting forward proposals
âthat stretch all the way from China to New York.â
9
At
a time when NASA was grounded and struggling to
adapt its programs to the Shuttleâs revealed shortcom-
ings, the NCOS discussed topics as wide-ranging as
self-replicating space factories, the International
Space Year, and the Big Bang. Arguably, all were
important to NASAâs future missions, but presenting
them in a single report merely made the view forward
seem more clouded.
The Reagan White House quietly shelved the NCOS
report; as Paine complained in an Aviation Week &
Space Technology opinion piece in September 1987,
â[T]he mandated presidential response to the commis-
sion has been delayed.â
10
It is hard to fault the spirit of
Paineâs report. But the Agencyâs challenge in 1986 was
to recover from the Challenger accident. If a plan for
NASAâs future in space was to be drawn up, it would
have to attempt to take into account the realities of U.S.
space flight in the mid-1980s. Such a plan was not long
in coming, thanks to heightened public interest in
NASAâs activities following the Challenger accident,
widespread concern that NASA had no long-term direc-
tion, and on-going efforts by Mars advocates.
The Ride Report
Sally Ride was a member of the 1978 astronaut class,
the first selected for Space Shuttle flights; in 1983 she
became the first American woman in space. She flew on
the Shuttle twice and sat on the Rogers Commission
investigating the Challenger accident before James
Fletcher, in his second stint as NASA Administrator,
appointed her as his Special Assistant for Strategic
Planning (18 August 1986) and charged her with
preparing a new blueprint for NASAâs future. She was
assisted by a 10-member panel and a small staff. The
result of her 11-month study was a slim report entitled
Leadership and Americaâs Future in Space.
Aviation Week & Space Technology reported initial
resistance inside NASA to releasing Rideâs report. The
magazine quoted an unnamed NASA manager who
said the agency was âafraid of being criticized by the
Office of Management and Budget.â The reportâs frank
tone may also have contributed to NASAâs reluctance.
In the end, Agency managers relented and published
2,000 copies in August 1987.
11
On 22 July 1987, Ride testified to the House
Subcommittee on Space Science and Applications. She
told the Subcommittee that the âcivilian space program
faces a dilemma, aspiring toward the visions of the
National Commission on Space, but faced with the real-
ities of the Rogers Commission report.â
12
Ride explained
that she had attempted to reconcile âtwo fundamental,
potentially inconsistent views.â âMany people,â she said,
believed that âNASA should adopt a major visionary
goal. They argue that this would galvanize support, focus
NASA programs, and generate excitement.â Others, Ride
stated, maintained that NASA was âalready overcom-
mitted for the 1990sââthat it would be âstruggling to
operate the Space Shuttle and build the Space Station,
and could not handle another major program.â
13
While Paineâs NCOS report urged rapid implementa-
tion of an expansive vision, Rideâs report outlined four
more limited leadership initiatives âas a basis for dis-
cussion.â She explained that her report was ânot
intended to culminate in a selection of one initiative
and elimination of the other three, but rather to pro-
vide concrete examples which could catalyze and focus
the discussion of the goals and objectives of the civil
space program, and of NASA efforts required to pursue
them.â
14
Ride thus deviated from the pattern Paine had estab-
lished in the STG report and continued in the NCOS
report; she did not propose a single âmaster plan.â In
her congressional testimony she explained her guiding
principle: âgoals must be carefully chosen to be consis-
tent with the national interest and . . . NASA capabili-
ties. It is not appropriate for NASA to set the goals of
the civilian space program. But NASA should lead the
discussion . . . , present options, and be prepared to
make recommendations.â
15
Rideâs four Leadership
Initiatives were as follows:
âą
Mission to Planet Earth:
âa program that
would use the perspective afforded from space
to study . . . our home planet on a global scale.â
Chapter 8: Challengers
âą
Solar system exploration using robots.
âą
Outpost on the Moon: an â. . . evolutionary, not
revolutionary . . . program that would build on.
. . the legacy of the Apollo Program . . . to con-
tinue exploration, to establish a permanent sci-
entific outpost, and to begin prospecting the
Moonâs resources.â
âą Humans to Mars: âa series of round trips to
land on the surface of Mars, leading to the
eventual establishment of a permanent base.â
The Mars mission, Ride asserted, should ânot
be another Apolloâa one-shot foray or a polit-
ical stunt.â
16
None of Rideâs four initiatives necessarily depended on
the others. Her âattempt to crystallize our vision of the
space program in the year 2000â in fact represented a
partial break from the space station-Moon-Mars pro-
gression that had typified most NASA advanced plan-
ning.
17
Rideâs approach caused confusion. For example,
Aviation Week & Space Technology magazine and many
newspapers incorrectly reported that she had called for
a Moon base as a precursor to a piloted Mars mission.
In fact, her report stated that the Moon was ânot
absolutely necessaryâ as a âstepping stoneâ to Mars.
18, 19
This reflected the influence of a NASA Advisory
Council Task Force led by Apollo 11 astronaut Michael
Collins. âI think it is a mistake to consider the [M]oon
as a necessary stepping stone to Mars,â Collins told
Aviation Week & Space Technology in July. âIt will not
get support politically, or from the U.S. public, which
thinks weâve âalready done the [M]oon.ââ
20
Ride person-
ally favored the Moon-Mars progression, however; she
wrote that it âcertainly makes sense to gain experience,
expertise, and confidence near Earth first.â
21
In common with the station-Moon-Mars progression,
Rideâs initiatives all included NASAâs Space Station.
This was a ground rule established by Fletcherânot
surprisingly, since the Space Station Program had
begun only three years before and was fiercely defend-
ed by NASA.
22
As explained earlier, in Challengerâs
aftermath, Space Station had become a two-phase pro-
gram. Ride pointed out that a decision on NASAâs
future course would impact the Phase II configuration.
She wrote that a âkey question for the not-too-distant
future is âhow should the Space Station evolve?ââ and
noted that Space Station evolution workshops in 1985
and 1986 had found that âa laboratory in space featur-
ing long-term access to the microgravity environment
might not be compatible with an operational assembly
and checkout facility [of the type envisioned to support
Moon and Mars exploration], as construction opera-
tions could disturb the scientific environment.â
23
Like the NCOS report, Rideâs report called for NASA to
increase its efforts to develop advanced space technology
for exploration missions.
She told the House
Subcommittee that âthe future of our space program lies
in careful selection and dedicated pursuit of a coherent
civil space strategy, and the health of our current space
program lies in determined development of technologies
required to implement that strategy.â
24
Rideâs report rec-
ommended Project Pathfinder, a program to develop
technologies that had been identified by a panel of NASA
engineers as crucial to future space programs. These
included aerobraking, automated rendezvous and dock-
ing, and advanced chemical propulsion. âUntil advanced
technology programs like Pathfinder are initiatedâ wrote
Ride, âthe exciting goals of human exploration will
always remain 10 to 20 years in the future.â
25
On 1 June 1987, Fletcher had created the NASA
Headquarters Office of Exploration, with Ride as
Acting Assistant Administrator for Exploration,
responsible for coordinating missions to âexpand the
human presence beyond Earth.â In explaining this
move, Fletcher said that â[t]here are considerableâ
even urgentâdemands for a major initiative to reener-
gize Americaâs space program . . . this office is a step in
responding to that demand.â
26
In her report, Ride wrote
that â[e]stablishment of the Office of Exploration was
an important first step. Adequate support of the Office
will be equally important.â She noted that there was
âsome concern that the office was created only to pla-
cate critics, not to provide a serious focus for explo-
ration. Studies relating to human exploration of the
Moon or Mars currently command only about 0.03 per-
cent of NASAâs budget . . . this is not enough . . . .â
27
Ride targeted the first Mars landing for 2005. Her
report pointed out, however, that âNASAâs available
resources were strained to the limit flying nine Shuttle
flights in one year.â âThis suggests,â it concluded, âthat
we should . . . proceed at a more deliberate (but still
aggressive) pace, and allow the first human landing to
70
Monographs in Aerospace History
Chapter 8: Challengers
occur in 2010. This spreads the investment over a
longer period.â
28
SAIC began designing the Mars mission in Rideâs
report in January 1987 and completed its study for the
NASA Headquarters Office of Exploration in
November 1987.
29
John Niehoff, the studyâs Principal
Investigator, was the âHumans to Mars Initiative
Advocateâ for the Ride Report. He had also worked on
The Planetary Societyâs 1984 Mars study (see Chapter
7). Niehoff âs team proposed a three-part Mars explo-
ration strategy:
âą
1990s: Robotic missions, including a global
mapper and a sample-return mission, would
âaddress key questions about exobiology and
obtain ground-truth engineering data.â This
period would also see research aboard the
Space Station into the effects of prolonged
weightlessness on astronaut health, and devel-
opment of âheavy-lift launch vehicles, high
energy orbital transfer stages, and large-scale
aerobrakes.â
âą
2000s: Piloted missions with round-trip times
of about one year, stay-times near Mars of 30 to
45 days, and Mars surface excursions of 10 to
20 days were the primary emphasis of the
SAIC study. These missions would explore
potential outpost sites and build up interplan-
etary flight experience. The one-year trip-time
was designed to reduce crew exposure to
weightlessness and radiation.
âą
After 2010: âA piloted base on Mars . . . a great
national adventure which would require our
commitment to an enduring goal and its sup-
porting science, technology, and infrastructure
for many decades.â
30
A large amount of energy would be required to get the
ship to Mars and back in about a year, which in turn
would demand a prohibitively large amount of propel-
lant. With an intent to reduce the number of heavy-lift
rocket launches needed to mount the expedition, SAIC
adopted a split/sprint mission mode based on a design
developed by students from the University of Texas and
Texas A&M University. This had a one-way, automated
cargo vehicle leaving Earth ahead of the piloted sprint
71
Humans to Mars: Fifty Years of Mission Planning, 1950â2000
Chapter 8: Challengers
Figure 21âScience Applications International Corporation developed its Mars mission plan for NASA during 1987. The pilot-
ed spacecraft (shown here in cutaway) would reach Mars with empty propellant tanks and dock with a waiting automated
cargo ship to fill up for the trip homeâa controversial departure from past Mars plans. (Piloted Sprint Missions to Mars,
Report No. SAIC-87/1908, Study No. 1-120-449-M26, Science Applications International Corporation, Schaumburg, Illinois,
November 1987, p. 9.)
vehicle on a low-energy trajectory. The cargo vehicle
would carry Earth-return propellants for the piloted
ship. To some this was worrisomeâif the sprint space-
craft could not rendezvous and dock with the cargo
vehicle, the crew would become stranded at Mars with
no propellants for return to Earth.
31
In phase 1 of SAICâs four-phase Mars mission, seven
heavy-lift rockets would launch parts for the cargo
vehicle and a reusable OTV, propellants, and cargo into
orbit near the Space Station. The OTV and cargo vehi-
cle together would measure 30.5 meters long and weigh
58.8 metric tons fully fueled. In addition to Earth-
return propellants for the piloted sprint vehicle, the
23.9-metric-ton cargo vehicle would carry the Mars lan-
der and scientific equipment.
According to SAICâs timetable, on 9 June 2003 the OTV
would push the cargo ship onto a minimum-energy
Mars trajectory, then separate and aerobrake in
Earthâs atmosphere to return to the Space Station for
reuse. The cargo ship would aerobrake into Mars orbit
on 29 December 2003.
Phase 2 would start one year after phase 1. Eight
heavy-lift launch vehicles would place propellants and
components for the piloted sprint vehicle and a second
OTV into Earth orbit near the space station. The OTV
used to launch the cargo vehicle would be combined
with the new OTV and the sprint vehicle to create a
73.9-metric-ton, 47.5-meter-long stack. The sprint vehi-
cle alone would weigh 19.4 metric tons fully fueled.
SAICâs sprint vehicle design was based on a 24.4-meter-
diameter saucer-shaped aerobrake. Four pressurized
living modules housing six explorers nestled within the
saucer. Twin restartable rocket engines drew propellant
from spherical liquid hydrogen and liquid oxygen tanks
mounted on top of the living modules. A docking tunnel
started at the conical ERV mounted on the aerobrakeâs
inner surface, passed through a âbridgeâ tunnel linking
the modules, and protruded beyond the twin engine
bells. The thick-walled ERV doubled as the shipâs radia-
tion shelter.
The sprint vehicle would leave Earth on 21 November
2004. The first OTV would accelerate the sprint ship
and second OTV, separate, and aerobrake in Earthâs
atmosphere for return to the Space Station. The second
OTV would also accelerate the sprint ship and return
to the station. The OTVs could be reused for future
sprint/split Mars expeditions. The sprint vehicle would
then fire its own rockets briefly to complete insertion
onto a low-energy trans-Mars trajectory. A six-month
trip to Mars would be possible, but Niehoff âs team
advocated an eight-month trajectory that would allow
a Mars flyby and abort to Earth if the cargo ship wait-
ing in Mars orbit with the piloted shipâs Earth-return
propellant failed during the crewâs flight to Mars. An
abort would have the Mars crew back on Earth on 5
January 2006. Assuming no abort became necessary,
the sprint ship would aerobrake into Mars orbit on 3
July 2005.
32
In phase 3, the sprint spacecraft would dock with the
cargo ship in Mars orbit. Three astronauts would board
the two-stage lander, undock, and land on Mars for 10
to 20 days. The crew in orbit, meanwhile, would per-
form scientific research, eject the sprint shipâs Mars
72
Monographs in Aerospace History
Chapter 8: Challengers
Figure 22âTwo Orbital Transfer Vehicles would push the
Science Applications International Corporation piloted
Mars ship out of Earth orbit. The company assumed that
Orbital Transfer Vehicles would be built for non-Mars pro-
grams in time to support its expedition, slated to reach Mars
in 2005. (Piloted Sprint Missions to Mars, Report No. SAIC-
87/1908, Study No. 1-120-449-M26, Science Applications
International Corporation, Schaumburg, Illinois, November
1987, p. 27.)
aerobrake, and transfer Earth-return propellant from
the cargo vehicle. The lander crew would then return to
Mars orbit in the ascent stage. On 2 August 2005, the
sprint vehicle would fire its engines for a high-energy
five-month sprint return to Earth.
Phase 4 would begin a few days before Earth arrival
(15 January 2006 for a nominal mission). The astro-
nauts would enter the ERV and separate from the
sprint spacecraft. The ERV would aerobrake into Earth
orbit while the abandoned sprint ship entered solar
orbit. A station-based OTV would recover the ERV;
then a Space Shuttle would return the crew to Earth.
On 26 May 1987, NASA had announced that, after fin-
ishing her study, Ride would leave NASA to become
Science Fellow in the Stanford University Center for
International Security and Arms Control.
33
In August,
John Aaron took over the Office of Exploration. Studies
begun in January 1987 to support the Ride report
became the basis for piloted exploration âcase studiesâ
in FY 1988. These examined a mission to Phobos, a
Mars landing mission, a lunar observatory, and a lunar
outpost-to-Mars evolutionary program. All commenced
with assembly of the Phase I Space Station.
34
Martin Marietta became the Office of Explorationâs de
facto exploration study contractor. On 15 May 1987,
NASA Marshall had awarded the $1.4-million Mars
Transportation and Facility Infrastructure Study con-
tract to the company, with SAIC in âan important team-
ing role,â and Life Systems and Eagle Engineering as
subcontractors.
35
The initial contract focus was in keep-
ing with Marshallâs propulsion emphasis; as in the
EMPIRE days, the Huntsville Center anticipated
developing new rockets for Mars.
However, because it was the only Mars-related NASA
contract when the Office of Exploration was estab-
lished, it became a mechanism for funding more gener-
al Mars-related studies. The contract, which lasted
until 30 April 1990, underwent 500 percent growth as
new study areas were grafted on. By the time it ended,
Martin Marietta had generated nearly 3,000 pages of
reports. Though Martin Marietta lost the contract to
Boeing when it was recompeted in late 1989, it served
to create an institutional expertise base for Martin
Marietta studies during the Space Exploration
Initiative (1989â93).
36
Opposition
NASA started as an instrument of Cold War competi-
tion with the Soviet Union. In the 1970s, having won
the race to the Moon, NASA was partly reapplied as an
instrument of international détente. The 1972 Space
Cooperation Agreement called for the Apollo-Soyuz
Test Project and other cooperative space activities. A
Soviet Soyuz spacecraft docked in Earth orbit with
Americaâs last Apollo spacecraft in July 1975. When the
agreement was renewed in 1977, it included plans for a
U. S. Shuttle docking with a Soviet Salyut space sta-
tion. By 1980, however, the Soviet invasion of
Afghanistan had undermined détente, ending virtually
all talks on piloted space cooperation.
37
In 1982, the Reagan White House let the Space
Cooperation Agreement lapse to protest continued
Soviet involvement in Afghanistan and martial law in
Poland. In the first major step toward renewed cooper-
ation, Senator Spark Matsunaga (Democrat-Hawaii)
sponsored legislation calling for renewal of the Space
Cooperation Agreement.
Congress passed the
Matsunaga resolution, and President Reagan signed it
into law in October 1984.
38
On 11 March 1985, Mikhail Gorbachev became the
Soviet Unionâs new leader. He set about implementing
a raft of new reform policies. Making them work meant
diverting resources from Cold War confrontation to
domestic production. A charismatic leader representing
a new generation of Soviet politicians, he encouraged
many in the West by working to thaw relations with the
United States.
Against this background, The Planetary Society part-
nered with the influential AIAA to hold the Steps to Mars
conference in Washington, DC, on the tenth anniversary
of Apollo-Soyuz. NASA Administrator James Beggs was
on hand to hear Carl Sagan and others promote a joint
United States-Soviet Mars expedition.
Sally Ride had written of the difficulty of reconciling
visionary and conservative space goals. The Planetary
Society Mars proposal fell into the former category.
Unlike some visionary goals, however, it proposed giv-
ing Mars exploration a political purpose, just as Apollo
lunar exploration had a political function in the 1960s.
Beggs endorsed U.S.-Soviet space cooperation, but cau-
73
Humans to Mars: Fifty Years of Mission Planning, 1950â2000
Chapter 8: Challengers
tioned that âwhen you get down to the nitty-gritty of
working out details, itâs not so easy.â
39
The U.S. and the Soviet Union renegotiated a new
Space Cooperation Agreement in November 1986.
Unlike its predecessors in 1972 and 1977, it contained
no provision for cooperative piloted missions. A month
later, Sagan published a prescient editorial in Aviation
Week & Space Technology. The Cornell University
astronomer asked, âWhat if sometime in the next few
years a general strategic settlement with the Soviet
Union is achieved . . . ? What if the level of military pro-
curement . . . began to decline?â Sagan believed that
â[I]t [was] now feasible to initiate a systematic program
of exploration and discovery on the planet Mars . . .
culminating in the first human footfalls on another
planetâ at a cost âno greater than a major strategic
weapons system, and if shared by two or more nations,
still less.â He added that Mars was âa human adventure
of high order, able to excite and inspire the most prom-
ising young people.â
40
The U.S. and the Soviet Union renewed the Space
Cooperation Agreement in April 1987. Emboldened,
The Planetary Society circulated The Mars Declaration
widely in late 1987. Declaration signatories included
former NASA Administrators and Apollo-era officials,
astronauts, Nobel laureates, actors, authors, politi-
cians, university presidents and chancellors, profes-
sors, pundits, composers, artists, and others. It called
for a joint U.S.-Soviet expedition to serve as a model for
superpower cooperation in tackling problems on Earth,
and it called Mars a âscientific bonanzaâ that could pro-
vide âa coherent focus and sense of purpose to a dispir-
ited NASAâ in the wake of the Challenger accident.
41
Mars, the Declaration continued, would give the U.S.
Space Station a âcrisp and unambiguous purposeâ as an
assembly point for Mars ships and as a laboratory for
research into long-duration space flight. Planetary
Society vice president and former JPL director Bruce
Murray was outspoken on this point. Reiterating what
George Low and Nixonâs PSAC had stated in the early
1970s, he told the AIAA in January 1988 that âthe prin-
cipal logic for the [S]tation is in the context of a Mars
goal.â
42
Meanwhile, the âfuture indicatorsâ the CIA had listed
for Harrison Schmitt in 1985 had begun to occur. On 15
May 1987, the Soviet Union launched the first Energia
rocket, the most powerful to leave Earth since the U.S.
scrapped the Saturn V. Energia functioned perfectly,
though its 80-metric-ton Polyus payload failed to
achieve orbit. On 21 December 1988, cosmonauts
Vladimir Titov and Musa Manarov returned to Earth
after a record 365-day stay aboard the Mir space sta-
tionâlong enough to have performed a one-year pilot-
ed Mars flyby.
Mikhail Gorbachev first publicly called for a joint U.S.-
Soviet Mars mission as Titov and Manarov boarded
Mir in December 1987. He told the Washington Post
and Newsweek before the May 1988 Moscow summit
that he would âoffer to President Reagan cooperation in
the organization of a joint flight to Mars. That would be
worthy of the Soviet and American people.â
43
On 24
May 1988, Pravda carried an article by Soviet space
flight leaders Yuri Semyonov, Leonid Gorshkov, and
Vladimir Glushko calling for a joint Mars mission.
44
Little progress was made toward Mars at the Moscow
Summit, but major strides were taken toward ending
the Cold War. Time magazineâs cover for 18 July 1988
showed a Viking photo of Mars with U.S. and Soviet
flags and the legend âOnward to Mars.â
Halfway through Titov and Manarovâs year-long stay
on Mir (7 July 1988), the Soviet Phobos 1 Mars probe
lifted off from Baikonur Cosmodrome on a Proton
rocket. Phobos 2 lifted off on 12 July. The twin probes
featured involvement by more than a dozen countries,
including the United States. They were designed to
orbit Mars and explore their namesake moon Phobos.
After rendezvous with the pockmarked little moon,
they would drop a âhopperâ rover and a small lander.
In retrospect, however, the probes were the Soviet Mars
program in miniatureâthey got off to a triumphant
start, then sputtered. On 31 August 1988, operators at
the Flight Control Center in Kaliningrad, near Moscow,
sent the Phobos 1 Mars spacecraft an erroneous radio
command that caused it to lose attitude control and
turn its solar arrays away from the Sun. Starved for
power, Phobos 1 failed just two months into its 200-day
flight to Mars. Phobos 2 reached Mars orbit on 29
January 1989. The spacecraft returned useful data on
Mars and Phobos; however, it failed in late March as it
neared the long-anticipated Phobos rendezvous.
At 6.5 metric tons each, the Phobos probes were the
heaviest Mars probes ever to leave Earth orbit. They
74
Monographs in Aerospace History
Chapter 8: Challengers
75
Humans to Mars: Fifty Years of Mission Planning, 1950â2000
took advantage of the minimum-energy launch oppor-
tunity associated with the September 1988 Mars oppo-
sition, the best since 1971.
Mars glowed bright orange-red in Earthâs skies as the
Space Shuttle Discovery was rolled to its Florida
launch pad for the first Shuttle flight since Challenger.
On 29 September 1988, as Earth overtook Mars in its
orbit and pulled ahead, Discovery lifted off on the 26th
flight of the Space Shuttle Program. The four-day, five-
crew STS-26 flight ended a 33-month hiatus in U.S.
piloted space flightâthe longest since the 1975-1981
Shuttle development period. By the time STS-27
launched in December, Mars was fading fast and the
U.S. Space Shuttle was no longer the worldâs only
reusable piloted spacecraft. The second Energia rocket
had launched on 15 November 1988 with a Buran
shuttle on its back for an unpiloted test flight.
The Mars planning community, though still small
and with few resources, was in ferment. New leader-
ship in the Soviet Union, the expanding Soviet space
program, and the thawing of U.S.-Soviet relations,
coupled with Americaâs return to piloted space flight
and growing public awareness of Mars, seemed to cre-
ate an opportunity. As will be seen in the next chap-
ter, newly elected President George Bush would take
up the mantle of President Kennedy and declare for
Mars. Though a failure, his initiative would not be
without significant results.
Chapter 8: Challengers
The study and programmatic assessment
described . . . have shown that the [Space]
Exploration Initiative is indeed a feasible
approach to achieving the Presidentâs goal . . . .
The last half of the 20th century and the first
half of the 21st century will almost certainly be
remembered as the era when humans broke the
bonds that bound them to Earth and set forth
on a journey into space . . . . Historians will fur-
ther note that the journey to expand the human
presence into the solar system began in earnest
on July 20, 1989, the 20th anniversary of the
Apollo 11 landing. (The 90-Day Study, 1989)
1
Space Wraith
Viewed as a space program, as it was intended to be,
the Space Exploration Initiative (SEI) was a failure.
Viewed as an âidea generatorâ for Mars exploration
planning, however, SEI was a successâsome concepts
it fostered dramatically reshaped subsequent planning
efforts.
2
It was also successful as a painful but neces-
sary growth process. SEI relieved NASA of weighty his-
torical baggage. It weaned large segments of the
Agency from its faith in the efficacy of Kennedyesque
Presidential proclamations, and it further weakened
the pull the station-Moon-Mars progression exerted on
senior NASA managers, a process that had first seen
high-level expression at NASA in the 1987 Ride report.
Like Apollo before it, the decision to launch SEI had
more to do with non-space policy than with its stated
space flight aims. SEI and Apollo were, however, dia-
metrical opposites in most other respects. Apollo
occurred at the Cold Warâs height, while SEI occurred
at its end. Apollo aimed at displaying American tech-
nological prowess to counter Soviet space successes,
while SEI aimed in part to provide new tasks for
defense-oriented government agencies and contractors
as the Soviet threat receded. Apollo was greeted with
public enthusiasm, while SEI was forgotten even as it
began. Finally, Apollo accomplished both its political
and space flight goals, while SEI accomplished neither.
The concept of a big Apollo-style space initiative was in
the air in the late 1980s. In late 1987 and early 1988,
the Reagan Administration considered and rejected a
âKennedy-style declarationâ calling for a Moon base or
a man on Mars. White House staffers explained that
they had lacked information adequate to make a âtech-
nically and fiscally responsible decision.â
3
The White
House opted instead for its National Space Policy
(February 1988) and for giving NASAâs Space Station a
nameâFreedom (July 1988). More importantly, it
requested $100 million in FY 1989 to start NASAâs
Pathfinder technology development program. The
Agency had asked for $120 million. In December 1987,
a National Research Council report estimated that
NASA would have to spend $1 billion a year on tech-
nology development for several years to make up for
past neglect. Despite this finding, the funding request
was poorly received in Congressânot a propitious sign
for big new initiatives.
4
Early in his Administration, President George Bush re-
established the National Space Council and put his
Vice President, Dan Quayle, in charge. On 31 May
1989, Bush directed NASA to prepare for a Presidential
decision on Americaâs future in space by proposing a
space goal with visible milestones achievable early in
the 21st century. The directive was said to have origi-
nated with OMB director Richard Darman and
Quayleâs advisors.
5
NASA Administrator Richard Truly,
Assistant Administrator for Exploration Franklin
Martin, and JSC director Aaron Cohen briefed Quayle
in June.
Bush revealed what they had told Quayle and launched
the SEI on the steps of the National Air and Space
Museum on 20 July 1989, the 20th anniversary of the
Apollo 11 Moon landing. Bush told his audience,
Space is the inescapable challenge . . . . We
must commit ourselves to a future where
Americans and citizens of all nations will
live and work in space . . . . In 1961 it took a
crisisâthe space raceâto speed things up.
Today we donât have a crisis. We have an
opportunity. To seize this opportunity, Iâm
not proposing a 10-year plan like Apollo. Iâm
proposing a long-range, continuing commit-
ment. First, for the coming decadeâfor the
1990sâSpace Station Freedom, our critical
next step in all our space endeavors. And
nextâfor the new centuryâback to the
Moon. Back to the future. And this time,
back to stay. And then, a journey into tomor-
row, a journey to another planetâa manned
mission to Mars . . . today Iâm asking . . . our
77
Humans to Mars: Fifty Years of Mission Planning, 1950â2000
Chapter 9: Space Exploration Initiative
able Vice President, Dan Quayle, to lead the
National Space Council in determining
specifically whatâs needed . . . . The space
council will report back to me as soon as pos-
sible with concrete recommendations to
chart a new and continuing course to the
Moon and Mars and beyond.
6
Aviation Week & Space Technology greeted the initiative
with skepticism and a pun, calling it a âspace wraith.â
âPresident Bush,â the magazine reported, âset forth a
long-term space plan without a budget and with no more
than a skeletal timetable. He then called for more
study.â
7
The initiative was, moreover, âsprungâ on
Congress with little âspadeworkâ by either the
Administration or by NASA.
8
This helped ensure opposi-
tion. Congress sent the Bush White House a clear mes-
sage by eliminating funds for the Pathfinder technology
development program from the FY 1990 NASA budget.
On 26 July, Truly and Martin briefed NASA employ-
ees on the Presidentâs call. They outlined a âbuilding
block approach to progressively more difficult human
missions.â
9
The proposal, a retread of the 1960s
Integrated Program Plan, ignored the less expansive
alternative program approach laid out by Sally Ride in
1987. Rideâs report was based on conservative projections
of NASAâs future resources, but the Truly and Martin
plan took it for granted that resources for a large, Apollo-
style program would automatically follow the Presidentâs
Kennedyesque proclamation.
10
Truly and Martin laid out the following timetable:
âą
1995-2000: Space Station Freedom operational;
robotic precursor spacecraft explore the Moon
âą
2001-2010: Lunar outpost; robotic precursors
explore Mars
âą
Post-2010: Mars expedition
The Moon and Mars goals would give âdirection and
focusâ to Space Station Freedom, Truly and Martin
stated, while the lunar outpost would give American
astronauts experience in living and working on
another world before confronting Marsâ greater
demands. The Moonâs proximity to Earth (âa three-day
tripâ) and scientific value made it an attractive way
station on the road to Mars. For its part, Mars was
SEIâs ultimate goal because it had âintrigued humans
for centuries,â was âscientifically excitingâ and âthe
most Earth-like planet,â and because it had resources
to support human life. Striving for Mars would âcement
long-term U.S. leadership in spaceâ by providing a
âchallenging focus for [the] space program.â
Truly and Martin told NASA civil servants that Bushâs
call was âa major institutional challenge for NASAâ
that would ârequire restructure of [the] [A]gency.â
NASA would seek to add staff and facilities and would
streamline its procurement system.
The 90-Day Study
The task of turning NASAâs SEI plan into a report for
Quayleâs National Space Council fell to an internal
NASA team led by Aaron Cohen. He had 90 days to
complete his study, which started on 4 August 1989.
The schedule was said to have been driven in part by
Bushâs desire to have an SEI implementation plan in
hand for his State of the Union speech in early 1990. In
September, Truly said that Cohenâs study involved 160
managers from across the Agency, of whom 100 were
based at JSC.
Mark Craig,
JSC Lunar-Mars
Exploration Program Office manager, headed the JSC
study team.
11
On 2 November 1989, Truly passed
Cohenâs report to President Bush.
Cohenâs report contained five âreference approachesâ
that followed âthe Presidentâs strategy: First, Space
Station Freedom, and next back to the Moon, and then
a journey to Mars.â There was, of course, nothing new to
this approach. In common with the 1969 Space Task
Group report, the reference approaches were in fact one
approach with multiple timetables for carrying it out,
not a range of alternate plans. NASA seemed to be say-
ing that there was only one way to explore the Moon
and Mars.
Approach A emphasized âbalance and speed.â Space
Station Freedom assembly would be completed in
1997, two to three years ahead of the completion date
planned at the time Cohenâs report was released.
Astronauts would return to the Moon in 2001 and per-
manently staff a lunar outpost the following year. By
2010 the outpost would produce 60 tons of oxygen per
year. In 2016, four astronauts would travel to Mars in
a transfer vehicle using lunar oxygen propellant and
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Monographs in Aerospace History
Chapter 9: Space Exploration Initiative
would spend 30 days on the surface. The year 2018
would see the first 600-day tour-of-duty in a perma-
nent Mars outpost.
Cohenâs Approach B aimed for the âearliest possible
landing on Mars.â The lunar and Mars activities out-
lined in Approach A would occur simultaneously,
requiring more spending in the 2000-2010 decade. The
first Mars expedition would occur in 2011.
Approach C strove for âreduced logistic support from
Earthââthat is, increased reliance on ISRU. Lunar
oxygen production would thus begin in 2005, earlier
than in Approach A.
Approach D was to pick Approach A, B, or C, then slip
all dates two to three years to allow Space Station
Freedom completion in 1999 or 2000. Americans would
return to the Moon in 2004.
Approach E assumed that the U.S. would undertake
Bushâs initiative, but on a âreduced scale.â Freedom
would be completed as scheduled in 1999 or 2000,
and Americans would return to the Moon in 2004.
The lunar outpost would be completed in 2012, and
astronauts would spend 30 days on Mars in 2016. A
60-day Mars stay would occur in 2018, followed by a
90-day stay in 2022. The Mars outpost would be acti-
vated in 2027.
Cohenâs report called for new heavy-lift rockets based
on Space Shuttle hardware or on the Pentagonâs
Advanced Launch System. The largest would place up
to 140 metric tons into orbit and have a launch shroud
up to 15 meters wideâlarge enough to cover reusable
aerobrake heat shields.
To support the Bush initiative, Space Station
Freedom would evolve from lab to spaceport through
four configurations. First, the baseline single truss
would be expanded to include the vertical lower keel
trusses and lower boom truss of the Dual Keel
design. The second configuration saw the addition of
a lunar spacecraft hangar and a second habitation
module to house four-person crews en route to the
Moon. The crew roster would rise to 12 in the third
configuration to support lunar spacecraft servicing
and increased life sciences research and Freedom
maintenance. The fourth configuration would see the
addition of the Dual Keel upper trusses and instal-
lation of a Mars spacecraft assembly facility.
The report called for increased civil service hiring
and new budget processes within NASA, but it
included no cost estimates. A JSC team led by
Humboldt Mandell performed a cost analysis and
prepared a cost section, but it was stricken and most
copies shredded by Trulyâs order because the costs
arrived at were deemed politically unacceptable.
12
Cost information was leaked from the National
Space Council, however, so suppressing the cost
data merely stymied informed discussion.
13
SEIâs
critics seized on the highest leaked cost estimates
without consideration of the cushion they contained
because they lacked complete informationâor, if
they had access to the details of the cost estimate,
they could safely ignore them because they were not
publicly available.
According to Mandell, The 90-Day Study plan âwas
over-costed by a considerable amount.â
14
The stricken
cost estimates included a 55 percent reserveââan
allowance incorporating both the cost estimating
uncertainties for individual developments (i.e., project-
level reserves) and allowances for changes in scope
(i.e., program-level reserves).â
15
The initial cost of a
permanent Moon base using Approach A and including
the 55 percent âcushionâ would be $100 billion in con-
stant 1991 dollars between 1991 and 2001. The Mars
expedition would cost an additional $158 billion
between 1991 and 2016 based on the same stipula-
tions. Thus, achieving the letter of Bushâs speechâa
return to the Moon to stay and a mission to Marsâ
would cost a total of $258 billion, of which 55 percent
($141 billion) was cushion.
16
Continuing operations would, of course, add to SEIâs
cost. In Approach A, operating the lunar base from
2001 to 2025 would cost $208 billion, while operating
a Mars outpost from 2017 to 2025 would cost $75 bil-
lion. Thus the SEI program cost for Approach A for 34
years, from 1991 to 2025, including operations and a
55 percent cushion, would come to $541 billion.
17
The cost summary had NASAâs annual budget climbing
from about $13 billion in 1990 to about $35 billion in
2007 for Approach A. At its peak, about half would be
allotted to Moon and Mars programs, meaning that the
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Humans to Mars: Fifty Years of Mission Planning, 1950â2000
Chapter 9: Space Exploration Initiative
average annual cost for Moon and Mars would be about
$15 billion per year.
18
A Quick Study
The 90-Day Study plan was NASAâs official proposal for
accomplishing SEI, but it was not the only SEI plan put
forward by the Agency. In the summer of 1989, an
Office of Exploration task force under Ivan Bekey per-
formed a âquick study . . . with analysis support by
Martin Mariettaâ which, it claimed, âdefined a much
more practical Mars program . . . by virtue of reducing
the scale of operations through judicious choices and
invention of a new launch vehicle concept.â
19
Focused on
Mars and relying heavily on Mars ISRU for propellant
production, it appears in retrospect as a premonition of
piloted Mars planning in the 1990s.
The study was based on Martin Marietta work performed
under the Marshall Transportation Infrastructure con-
tract, as well as on the Phobos and Mars Case Studies.
Bekeyâs task force briefed Truly on its proposal in the
summer of 1989, but it had little obvious influence on The
90-Day Study.
20
Bekey presented the concept at the 40th
International Astronautical Federation Congress in
Malaga, Spain, in October 1989, just before Truly sent
Cohenâs report to President Bush.
The Bekey task force proposed that astronauts go first
to Phobos. There they would set up an ISRU propellant
plant for making propellants from Phobos materials,
which are believed to be water-rich. Bekeyâs group also
proposed to minimize impact on Space Station Freedom
by using heavy-lift launch vehicles to launch a few
large components rather than resorting to on-orbit
assembly of many small components. Mission rate
would be kept low to reduce spending rate. The piloted
Mars expedition would be preceded in the 1990s by a
âpreparatory programâ including automated precur-
sors, technology development, and biomedical research.
The Moon played no mandatory role in Bekeyâs pro-
posed Mars program.
Bekeyâs task force found that, assuming an opposi-
tion-class trajectory with a Venus flyby for the initial
Phobos expedition and a conjunction-class trajectory
for the Mars landing expeditions, the maximum
spacecraft mass at Earth-orbit departure for a Phobos
expedition was similar to the minimum mass for a
Mars landing expeditionâabout 700 tons. Therefore,
the short Phobos mission in 2004 could act as a
âshakedown cruiseâ for the Mars landing mission
spacecraft design, helping to minimize risk to the
crew during the longer landing missions.
Three astronauts would travel to Phobos with a
piloted Mars lander, which would touch down
unpiloted on Mars to act as a backup habitat for the
2007 Mars landing expedition crew. The 2004 crew
would spend a month at Phobos, during which they
would demonstrate an automated ISRU pilot plant.
Three expeditions would then travel to Marsâ surface to
set up infrastructure for a Mars outpost. Five astro-
nauts would launch to Mars in 2007, land near the
backup habitat from the 2004 mission, and spend a
year on the surface. On the next expedition, five astro-
nauts would set up the first half of a propellant pro-
duction facility on Phobos and land on Mars.
Expedition 4 would set up the remainder of the propel-
lant plant, âreadying the Mars infrastructure for a sus-
tained series of visitsâ that would establish a perma-
nent outpost on Mars.
The task force Phobos/Mars spacecraft design consist-
ed of a large dish-shaped aerobrake with twin Space
Station Freedom-derived cylindrical habitats. The
spacecraft would rely on tethers to create artificial
gravity; the astronauts would reel out the habitat
modules from the aerobrake, then rotate the assem-
blage end over end to produce artificial gravity.
Bekey proposed launching Mars ship components and
propellant on Shuttle-derived Shuttle-Z rockets, which
would include three or four Space Shuttle Main
Engines (SSMEs), a strengthened External Tank, and
two Solid Rocket Boosters. Shuttle-Z would use existing
Kennedy Space Center Shuttle facilities and cost about
the same per launch as the Shuttle, âbut with 4-6 times
the payload.â
28
By using the Mars transfer stage as the Shuttle-Z
third stage, up to 164 tons could be placed in low-
Earth orbit. This would permit the Phobos/Mars
spacecraft to be fully assembled with âat mostâ two
Shuttle-Z launches. Three Shuttle-Z launches would
refuel the Mars transfer stage in orbit. A similar con-
cept was proposed in the 1971 MSC PMRG study. The
crew would then board the ship from a Space Shuttle
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Monographs in Aerospace History
Chapter 9: Space Exploration Initiative
orbiter and fire the refueled transfer stage to leave
Earth orbit for Mars.
The Bekey task force estimated that the total weight
launched per year to carry out its Mars program would
be about half that needed to carry out the split-sprint
mission plan defined by SAIC for the 1987 Ride Report.
Bekeyâs admittedly optimistic preliminary cost esti-
mate was $40 billion for two landings on Mars.
20
The Great Exploration
Alternatives to The 90-Day Study also surfaced outside
NASA. In mid-September, at about the time Cohen pre-
sented his initial briefing on his study to the National
Space Council,
Lawrence Livermore National
Laboratory (LLNL) engineers, led by Lowell Wood,
briefed Quayle on their Great Exploration plan for
SEI.
21
LLNL, which was operated by the University of
California under contract to the U.S. Department of
Energy, was associated with design and test of nuclear
weapons, as well as research into advanced particle
beam and laser weapon systems.
The Livermore plan was not well received by NASA,
which saw it as an effort to invade its territory.
22
The
meaning of the âopportunityâ Bush mentioned in his 20
July speech thus seemed clearâSEI was to be an
opportunity for the national laboratories to expand
their bailiwick. According to some participants, one
purpose of SEI was to provide work for Federal govern-
ment agencies and contractors suffering cut-backs
because the Cold War was ending. Cohenâs study had,
in fact, taken into account the need to provide tasks for
organizations such as the Army Corps of Engineers and
the Department of Energy labs.
23
NASAâs understand-
ing was, however, that NASA would be in charge.
24
LLNLâs Great Exploration plan drew on its 1985
Columbus lunar and 1988 Olympia Mars studies.
25, 26
Wood and his colleagues explained that their plan
respected âcontemporary politico-economic realities,â
which would not tolerate a $400-billion space program
lasting three decades. Their plan, they claimed, would
require a decade and cost only $40 billion.
27
The Livermore team called for âmanned space explo-
ration as though it were a profit-seeking enterpriseâ
with âswift exploration, settlement and infrastructure
creation.â âEach step,â they explained, would leave
âmajor operational legaciesâand commitmentsâ so
that âLunar and Martian Bases, once manned, never
need be unmanned thereafter.â They also called for
extensive use of off-the-shelf technology to launch and
outfit inflatable structures (âcommunity-sized space
suitsâ), including an Earth-orbital station, âGas
Stationâ propellant depots, and Moon and Mars surface
bases.
28
The Great Exploration program would commence in
mid-1992, when a single Titan VI or HL Delta rocket
would launch a 50-metric-ton folded Earth Station and
Gas Station payload with an Apollo CM on top. The
stations would deploy and inflate automatically in
orbit under the crewâs supervision. The Earth Station
would consist of seven 15-meter-long sausage-shaped
modules arranged end to end. It would rotate end over
end four times each minute to create artificial gravity
that would vary from deck to deck over the length of
the station, thus providing crews with lunar and
Martian gravity experience. The Gas Station would
use solar power to electrolyze water into liquid hydro-
gen/liquid oxygen spacecraft propellants. Water would
be launched by competing companies and purchased
by the government from the lowest bidder.
In late 1994, a single rocket would launch a 70-metric-
ton folded Lunar Base with an Apollo CM-based Earth
Return Module on top. The Lunar Base would refuel at
the Gas Station, fly to the Moon, and inflate on the sur-
face. The astronauts would live in Spartan conditions,
with crew rotation every 18 months. A lunar surface
fuel factory and lunar-orbit Gas Station would be
established when the second crew arrived in late 1996.
The 70-metric-ton Mars Expedition ship would be
launched in late 1996, inflated in Earth orbit, and refu-
eled at the Gas Station. It would then fly to Mars orbit
and visit Phobos or Deimos before landing on Mars.
The Mars Base would inflate on the surface, and the
first crew would move in for a 399-day stay. They would
mine Martian water to manufacture propellants for a
rocket-powered hopper.
The plan was innovative, but could it work? NASA
managers and engineers thought not. The national lab-
oratories, however, had supporters in the White House
and on the National Space Council, among them Vice
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Humans to Mars: Fifty Years of Mission Planning, 1950â2000
Chapter 9: Space Exploration Initiative
82
Monographs in Aerospace History
President Quayle. They held up the LLNL proposal as
a good example of âinnovative thinking.â
29
Faced with two rival plans for carrying out his initia-
tive, in December Bush asked the National Research
Council (NRC) to examine the studies. H. Guyford
Stever, science advisor to Presidents Nixon and Ford
and a former Director of the National Science
Foundation, chaired the NRCâs Committee on Human
Exploration of Space. Among its 14 members were
Apollo 10 astronaut Thomas Stafford and (until his
death on 31 January 1990) Apollo program manager
Samuel Phillips.
The Stever Committee report, unveiled on 7 March
1990, stated that the LLNL approach entailed ârela-
tively high riskâ and underestimated âthe many
practical and difficult engineering and operational
challengesâ of exploring space.
30
The report threw
cold water on the push to give SEI over to the
national laboratories by stating that âNASA has the
organizational expertise and demonstrated capabil-
ity to conduct human space exploration . . . . To
attempt to replicate such expertise elsewhere would
be costly and time-consuming.â
31
The Stever Committee also pointed out a basic truth
applicable to all large space projects: that the âpace at
which the initiative should proceed, while clearly
influenced by scientific and technical considerations, is
inherently determined by social and political decision-
making processes in which non-technical constraints,
such as the sustainable level of resource commitment
and acceptable level of risk[,] are paramount.â
32
In
other words, policy makers bore as much responsi-
bility for setting SEIâs pace, price tag, and chances
for eventual success as the engineers, and they
would have to make firm decisions before the engi-
neers could plan effectively and proceed.
The Stever Committee then called for more studies,
stating that âthe [N]ation is at a very early stage in
the developmentâ of its Moon and Mars plans (this
despite the many studies performed inside and out-
side NASA over the decades). âNone of the analyses
to dateâThe 90-Day Study, The Great Exploration,
or, indeed, this reportâshould be regarded as provid-
ing more than a framework for further discussion,
innovation, and debate,â
33
it stated, then added that
â . . . the eventual choice of mission architecture will
incorporate the ideas from a variety of concepts, some
that now exist and others that will arise in the future
. . . . The variety of concepts should be regarded as a
âmenuâ of opportunities.â
34
In late February, a week before the Stever Committee
report was publicly released, President Bush directed
that NASA should be the âprincipal implementary
agencyâ for SEI, with the Departments of Defense and
Energy in âmajor roles.â
35
Within a week of the reportâs
release, President Bush followed its advice and called
for more study. He asked that at least two substantial-
ly different reference architectures for SEI be produced
over the next several years.
Idea collection for the Stever Committeeâs âmenuâ had
begun in mid-January 1990, when the Aerospace
Industries Association, an organization representing
aerospace contractors, had met to start a process of
gathering ideas to turn over to NASA. The Agencyâs
Office of Aeronautics and Space Technology served as
ad hoc coordinator for this effort.
36
NASA also enlisted
Rand Corporation to manage a campaign to solicit
ideas from industry, universities, national labs, and the
general public. NASA Administrator Truly led a U.S.
Government interagency effort. This broad gathering of
ideas became known as the SEI Outreach Program.
Ideas collected through the Outreach Program were to
be reviewed by an independent SEI Synthesis Group,
which would then issue a report. The Synthesis Group
approach had been recommended by the Aerospace
Industries Association in April. On 16 May 1990,
Congress agreed to provide $4.55 million for the
Outreach Program, but not without a price. NASA had
to agree that it would release no SEI-related contracts
to industry until 1991. As one congressional staffer
explained, this deferment was designed âto avoid rais-
ing expectations in the private sector, given the incred-
ible [Federal] budget restraints.â The Agency also
agreed to defer $5 million in internal NASA study work
until 5 August 1990.
37
On 31 May, Truly introduced Tom
Stafford as Synthesis Group chair.
Paul Bialla, NASA Programs Manager for General
Dynamics, expressed well the skepticism many in
industry felt toward the SEI Outreach Program. âFor
the most part, our ideas have already been shared with
NASA,â he told Space News. âThrowing the door open to
everyone is simply going to delay the process.â
38
Chapter 9: Space Exploration Initiative
A Political Liability
The Outreach Program was SEIâs most far-reaching
contribution to Mars expedition planning, for it
compiled a large body of ideas for how to send
humans to Mars. In terms of implementing SEI,
however, the Outreach Program amounted to a
means of allowing the abortive initiative to fade qui-
etly after it had become an obvious political liabili-
ty for the Bush Administration.
Even as the Outreach Program began, SEI was mor-
tally wounded. The Bush Administrationâs NASA
budget request for FY 1991 was $15.1 billion, a 23
percent increase over FY 1990. This included $216
million to start SEI. Two days of NASA budget hear-
ings in mid-March 1990 showed, however, that the
Moon and Mars initiative enjoyed almost no support
in Congress. By the summer of 1990, it was writ
largeâno matter what good ideas the Outreach
Program might produce, SEI stood almost no chance
of gaining congressional support.
It was a two-part problem. On the one hand, the
Democrat-controlled Congress was not eager to hand
the Republican Bush Administration any victories,
especially after it had cast its 1988 Presidential candi-
date, Michael Dukakis, as a spend-thrift Democrat.
39
More importantly, however, the late 1980s and early
1990s were marked by an enormous Federal debtâ$3
trillion in 1990âand annual budget deficits. Budget
problems alone made it unlikely that a new space ini-
tiative would be well received, even if it didnât have a
rumored price tag of half a trillion dollars.
On fiscal grounds, SEI opposition was bipartisan. Bill
Green (Republican-New York), a member of the House
Appropriations Committee, said, â[G]iven the current
budget situation, I would not anticipate a significant
start on Mars in the near future.â
40
Robert Traxler
(Democrat-Michigan),
chair of the House
Subcommittee on Housing and Urban Development
and Independent Agencies, summed it up succinctly:
âBasically, we donât have the money.â
41
On 1 May 1990, President Bush called congressional
leaders to the White House to lobby for SEI. Richard
Darman sought to declare NASAâs proposed budget
increase exempt from mandatory cuts imposed by
Gramm-Rudman deficit reduction legislation, and
Bush proposed that aerospace technology cuts should
come from the Defense budget, not from NASA.
42
The
congressional response was quick in coming. On 3 May
1990, Senator Albert Gore (Democrat-Tennessee), chair
of the NASA Authorization Panel, told his fellow legis-
lators that âbefore discussing a mission to Mars, the
Administration needs a mission to reality.â
43
Bush used his 11 May commencement address at Texas
A&M University to signal SEIâs importance to his
administration. His speech was historicâin it he
became the first U.S. President to set a target date for
an American expedition to Mars. âI am pleased to
announce a new age of exploration,â he told the crowd,
âwith not only a goal but also a timetable: I believe that
before America celebrates the 50th anniversary of its
landing on the Moon [in 2019], the American flag
should be planted on Mars.â
44
Congress, however, handed Bush his first clear defeat
in mid-June, when a House panel eliminated all funds
for SEI from the FY 1991 NASA budget. On 20 June
Bush declared that he would fight for his Moon and
Mars program. His Administration had, he said,
âmatched rhetoric with resources.â The full House elim-
inated all SEI funds at the end of June.
45
On top of issues of party and finance were badly timed
NASA problems not directly related to SEI. These
raised inevitable questions about the desirability of
committing the Agency to a major new initiative when
it appeared it could not handle what it already had. In
late June, NASA announced that the $1.5-billion
Hubble Space Telescope, launched into orbit on 24 April
1990, was rendered myopic by an improperly manufac-
tured mirror. At the same time, the Shuttle fleet was
grounded by persistent hydrogen fuel leaks. The three
orbiters sat on the ground for five months while NASA
engineers struggled with the problem.
On the first anniversary of Bushâs SEI speech, a NASA
panel headed by former astronaut and spacewalker
William Fisher announced that Space Station Freedom
would need 6,200 hours of maintenance spacewalks
before it was permanently staffed and 3,700 hours of
maintenance spacewalks each year thereafter. This
would cut deeply into time available for research
aboard the orbiting space laboratory.
46
The Fisher
Panelâs findings helped lead to a new round of station
redesign in 1990 and 1991. In an effort to reduce cost
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Chapter 9: Space Exploration Initiative
and complexity, the potential for Phase II expansion to
the Dual Keel design was eliminated, along with the
option for hangars, fueling facilities, and other Moon-
and Mars-related systems.
47
Space Station Freedom thus lost virtually all hope of
being useful for Mars transportation. It remained
important, however, as a place to gather data on the
biomedical effects of long-duration space flight as part
of efforts to minimize risk to future Mars crews. Not
coincidentally, Mars plans that ignored the Station,
except to say that they did not intend to use it, began
to proliferate. NASA internal planning, however, con-
tinued to place Space Station Freedomâor some future
stationâsquarely on the path to Mars.
In October, House and Senate conferees agreed to an
FY 1991 NASA budget of $13.9 billion. While this con-
stituted an increase of $1.8 billion over NASAâs FY
1990 budget, it included no funds for SEI. Bush bowed
to the inevitable and signed the appropriation into law.
A New Initiative
By the fall of 1990, the course of piloted space flight
over the next decade was taking shape. Bush had men-
tioned international space cooperation in his speech of
20 July 1989. SEI, however, stressed U.S. space leader-
ship, which implied competition with the Soviet Union.
The Soviets had built up an impressive space infra-
structure in the 1970s and 1980s. By 1990, however,
with economic and political reforms underway in their
country, they could no longer afford to use it.
As early as March 1990, Bush had directed the
National Space Council to pursue space cooperation
with the Soviets in an effort to encourage and support
Mikhail Gorbachevâs on-going reforms. On 8 July 1990,
Bush agreed to let U. S. commercial satellites fly on
Soviet rockets. On 25 July 1990, the United States and
Soviet Union agreed to fly a NASA Mission to Planet
Earth instrument on a Soviet satellite scheduled for
launch in 1991. In October 1990, Quayle told reporters
that âwe are in serious discussions with the Soviet
Unionâ on flying an American astronaut on Mir and a
Soviet cosmonaut on the Shuttle.
48
Yuri Semyonov, director of NPO Energia, the leading
Soviet astronautics design bureau, promoted joint U.S.-
Soviet piloted Mars exploration at space conferences in
Montreal in 1990 and Houston in 1991.
49
Would-be Mars
explorers saw in this an opportunity. At the Case for
Mars IV conference in June 1990, for example, Benton
Clark suggested using the Energia heavy-lift rocket to
transport Mars spacecraft propellants to orbit. âUse of
the Soviet booster would,â he declared, âmake the
dependency between the cooperating countries simple
and straightforward.â
50
This represented a dramatic shift
from the early 1980s, when Harrison Schmitt pushed for
the LANL/NASA Manned Mars Missions study to help
counter Soviet Mars moves.
In July 1990, Semyonov and Leonid Gorshkov, head of
Energiaâs orbital stations department, published an
article on Energiaâs Mars plans in the Soviet popular-
audience publication Science in the USSR.
51
The con-
figuration of the Mars spacecraft depended, they
wrote, on the choice of âpowerplant.â They rejected
chemical propulsion, saying that an all-chemical Mars
ship would weigh upwards of 2,000 metric tons at
Earth-orbit departure. A nuclear-thermal rocket Mars
ship would weigh about 800 metric tons. More prom-
ising, however, were solar-electric or nuclear-electric
propulsion systems which could reduce ship mass to
between 350 and 400 metric tons.
Semyonov and Gorshkov wrote that Soviet âaerospace
technology is advanced enough to make a mission to
Mars a reality,â then summarized existing Soviet capa-
bilities. In addition to the Energia rocket (âcapable of
lofting into Earth orbit whole sections of a spacecraft
for final assemblyâ), the Soviet Union had âperfected
the automatic docking procedures for putting together
a spacecraft from sections in orbitâ through more than
50 flights of automated Progress freighters to space
stations. Semyonov and Gorshkov claimed that â[m]ost
of the problems that would be faced by a crew on a long
voyage to Mars in zero-gravity have been resolvedâ
through 20 years of Soviet space station flights âin an
environment very similar, if not identical, to that of a
Mars mission.â Finally, they reported that âelectric . . .
engines of the required parameters have been flaw-
lessly performing on Earth.â
52
In 1991, Energia released a Mars expedition report
reflecting âthe expediency to take into account . . .
world public opinion, which [is] against the launch of
nuclear powerââan aversion reinforced by the Soviet
Unionâs own April 1986 Chernobyl nuclear reactor
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Chapter 9: Space Exploration Initiative
meltdown.
53
NPO Energiaâs 355-metric-ton solar-
electric Mars spacecraft would reach Earth orbit in
sections strapped to the sides of five Energia heavy-
lift rockets. The designers envisioned a pair of 40,000-
square-meter solar panels supplying 7.6 megawatts of
electricity at Earthâs distance from the Sun and 3.5
megawatts at Mars.
The crew section of Energiaâs Mars ship design includ-
ed two cylindrical modules linked end to end. The large
living module would contain a âvitamin greenhouseâ
and individual cabins for four cosmonauts. Water tanks
would surround the cabins to shield them from radia-
tion. Over the course of the expedition the water would
be gradually consumed and replaced by âwaste bricks.â
An airlock for spacewalks and electric motors for point-
ing the solar arrays would separate the living module
from a smaller control/laboratory module. The space-
craftâs lithium-propellant electric propulsion system
would be housed in twin modules attached to the sides
of the control/lab module.
According to the report, Soviet designers had studied
conical piloted Mars landers outwardly similar to the
NAR MEM from 1969 to 1971.
54
Their 1991 Mars
Landing Vehicle was, however, a cylinder with a coni-
cal forward section, a shape selected in part because it
fit within the Energia rocketâs payload envelope. The
two-person landerâs cylindrical section would house
an ascent stage with a docking unit on top. The 60-
metric-ton Mars Landing Vehicle would land horizon-
tally. The cosmonauts would live in the landerâs for-
ward cone while on the Martian surface. After a week
on Mars, the cosmonauts would blast off in the ascent
stage to rejoin their comrades aboard the orbiting
Mars ship.
At journeyâs end, the crew would separate from the
Mars ship in the 10-metric-ton Earth Return Vehicle,
a conical reentry module resembling the Apollo CM.
The Earth Return Vehicle was designed for land land-
ingâlike the Soyuz space station transport, it would
include solid-fueled soft-landing rockets under its
ablative heat shield.
Bush and Gorbachev formally agreed at their July
1991 summit meeting to fly an American astronaut to
Mir and a Soviet cosmonaut on the Space Shuttle.
Less than two weeks later, in August 1991, communist
hardliners launched an abortive coup dâetat against
Gorbachev, triggering the collapse of the Soviet
Union. The following summer, Bush confirmed the
July 1991 cooperation agreements with Russian
President Boris Yeltsin. The first Russian cosmonauts
arrived in Houston for Space Shuttle flight training in
November 1992.
Space cooperation expanded dramatically under
President William Clinton beginning in 1993. Space
Station Freedom was redesigned as the International
Space Station, which incorporated Russian hardware
originally built for the Soviet Mir-2 space station.
Mars-related cooperation, however, remained small in
scale. For example, NASA Lewis researchers worked
with Russian engineers on electric thrusters.
America at the Threshold
The SEI Synthesis Group released its report America
at the Threshold in May 1991.
55
The report, though
written at a time when U. S.-Soviet space cooperation
was becoming increasingly important to NASAâs future,
contained little on cooperation. The Synthesis Group
report was the last in the series of high-profile docu-
ments proposing future directions for NASA that had
begun with the National Commission on Space report
in 1986.
Stafford headed a group of 22 experts from NASA and
the Departments of Energy,
Defense,
and
Transportation. They included retired JSC director
Christopher Kraft and retired JSC engineering director
Maxime Faget. Robert Seamans, retired from top
NASA, Air Force, and Department of Energy posts, was
Staffordâs co-chair. They set up shop with a staff of 40
in Crystal City, Virginia, just outside Washington, DC.
The SEI Outreach Program provided the Synthesis
Group with about 500 inputs from the 44,000-member
AIAA. The Aerospace Industries Association, mean-
while, organized corporate briefings. These included a
presentation by Martin Marietta featuring the Mars
Direct plan. NASA took out newspaper advertisements
around the country and set up toll-free telephone num-
bers to receive ideas from the public. About 900 concepts
were submitted to Rand Corporation by early
September. The national laboratories turned over their
ideas during September. All told, the Synthesis Group
had about 2,000 inputs in hand in late September.
56
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The Synthesis Group was to submit at least two concepts
based on these inputs to Truly, who would forward them
to the National Space Council. A two-year NASA study
would follow, during which the Agency would attempt to
identify critical technologies needed to carry out the con-
cepts proposed by the Synthesis Group.
In June 1991, the Group distributed 40,000 copies of its
colorful report, emblazoned with the U. S. Presidential
Seal, to industry, educators, government agencies, and
international organizations. The report outlined four
SEI architectures. In all of them, the ultimate goal was
landing Americans on Mars. The Moon would serve as a
rehearsal stage; nuclear systems would push spacecraft
and power bases; and heavy-lift rockets would blast
everything into orbit. Including nuclear propulsion was,
as in the 1960s, in part a concession to Los Alamos,
which had begun stumping for SEI nuclear systems as
early as February 1990.
57
In none of the architectures was Space Station Freedom
an element of Mars transportation infrastructure. In
September, Aviation Week & Space Technology quoted
Stafford as saying, âI know when I went to the Moon . . .
on Apollo 10, I did not have to stop at a space station.â
58
This was a radical departure from SEIâs ground rules. It
was, in fact, a deviation from ground rules that had
guided Mars planning since the time of the Apollo
Moon missions, when NASA had first began to push for
a space station.
Staffordâs Architecture I emphasized Mars exploration
but would spend five years on the Moon first. In 2005, a
heavy-lift rocket would launch an automated cargo lan-
der/habitat to the Moon. A second heavy-lift rocket
would launch a crew of six to lunar orbit. Five astronauts
would land on the Moon near the cargo lander; the sixth
astronaut would mind the mothership in lunar orbit,
just as the CM Pilot had minded his craft during Apollo
Moon landing missions. The surface crew would stay on
the Moon for 14 Earth days (one lunar daylight period).
In 2009-10, after four more heavy-lift rocket launches
and two more lunar expeditions, a six-person Mars
rehearsal crew would carry out a 300-day Mars expedi-
tion simulation in lunar orbit and on the Moon. After
that, the Moon would not be visited again.
In 2012, the ninth heavy-lift rocket of Synthesis Group
Architecture I would launch the first nuclear rocket of
the program. It would push an automated cargo lander
to Mars. The cargo lander would include a habitat iden-
tical to that landed on the Moon. The first six-person
Mars crew would leave Earth in 2014 on the tenth
heavy-lift rocket. After a flight lasting approximately
120 days, they would decelerate into Mars orbit using
their nuclear-thermal rocket, separate from the Mars
transfer habitat, and land near the 2012 cargo lander.
The crew would spend 30 days testing systems and
exploring before returning to the transfer spacecraft
and firing the nuclear rocket for return to Earth. In the
same launch opportunity, the eleventh heavy-lift rocket
of the program would launch a cargo lander for the 2016
Mars expedition, which would spend 600 days on Mars.
The report stated that Architecture I was conducive to
more rapid execution (first Mars landing in 2008) if pro-
vided with ârobustâ funding.
The other architectures were generally similar.
Architecture II, âscience emphasis for the Moon and
Mars,â was designed to characterize the Moon and
Mars scientifically through wide-ranging exploration
and visits to multiple scientifically interesting landing
sites. Architecture III, âMoon to stay and Mars explo-
ration,â emphasized a permanent lunar base. The base
would achieve 18-person permanent staffing in 2007. A
total of 47 six-person piloted expeditions would reach
the Moon between 2004 and 2020, and the first piloted
Mars landing would occur as in Architecture I.
The Stafford Group noted that âspace is a unique store
of resources: solar energy in unlimited amounts, mate-
rials in vast quantities from the Moon and Mars, gases
from the [M]artian atmosphere, and the vacuum and
zero gravity of space itself ââhence Architecture IV,
which emphasized âspace resource utilization.â
59
Lunar
ISRU would aim first for self-sufficiency; then it would
export to Earth electricity and Helium-3 for fusion
reactors. Mars ISRU would aim solely to provide self-
sufficiencyâthe planetâs greater distance would make
exports to Earth impractical, the report stated. The
Mars rehearsal on the Moon would take place as
described in Architecture I, and Mars expeditions
would occur in 2016 and 2018. The second expedition
would establish an experimental greenhouse. Both
expeditions would manufacture propellants for their
rovers from Martian air.
The report made organizational recommendations for
carrying out its program. It called upon NASA to
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Humans to Mars: Fifty Years of Mission Planning, 1950â2000
establish âa long range strategic plan for the [N]ationâs
civil space program with the Space Exploration
Initiative as its centerpiece,â and asked President
Bush to âestablish a National Program Office by
Executive order.â In addition, it advocated advanced
technology development programs.
60
The SEI Synthesis Group had produced a cut-price ver-
sion of The 90-Day Studyâa disappointing outcome,
given the magnitude of the Outreach Program. Few
Americans took notice of America at the Threshold, and
few of its recommendations were implemented. SEI
funding fared no better in FY 1992 and FY 1993 than
in the previous two years. The planned two-year follow-
up study of critical technologies did not take place.
NASA disbanded the Headquarters Exploration Office
in late 1992. The JSC Exploration Directorate closed
down a few months later.
61
The poorly attended Case for
Mars V conference in May 1993 became SEIâs wake. By
the beginning of 1994, Mars planning across NASA
threatened to slip back into its post-Apollo slumber.
Chapter 9: Space Exploration Initiative
Recent developments in the exploration of
Mars have served to focus attention once
again on the possibilities for human explo-
ration of that planet. The unprecedented
interest shown in the recently published evi-
dence pointing to past life on Mars and in the
Mars Pathfinder mission indicates that
exploration of our solar system has not
become so commonplace that the public can-
not become surprised and fascinated by the
discoveries being made. And these events
have also rekindled the questions not of
whether, but when will humans join the
robots in exploring Mars. (Kent Joosten,
Ryan Schaefer, and Stephen Hoffman, 1997)
1
Mars Direct
Like the STG, NCOS, and The 90-Day Study teams
before it, the SEI Synthesis Group opted for a âbrute-
forceâ approach to piloted Mars exploration requiring
such big-ticket items as heavy-lift rockets that dwarfed
the old Saturn V, nuclear-thermal propulsion, and a
lunar outpost. As has been seen, this approach has
never gained much support. Proposing it repeatedly
over the past 30 years has succeeded mainly in ingrain-
ing the belief that Mars exploration must be exorbi-
tantly expensive (more expensive than a small war, for
example) and needs decades to achieve its goal.
Subsequent NASA Mars plans have sought to apply
technologies new and old to reduce cost and tighten the
schedule. They have begun the slow process of expung-
ing the perception that a Mars mission must be con-
ducted in a costly way.
Since 1992, NASA has based most of its Mars plans on
the Mars Direct concept developed in 1990 by Martin
Marietta. Mars Direct originated in Martin Marietta-
sponsored efforts to develop SEI concepts. The plan
has had staying power in part because it is an appeal-
ingly clever synthesis of concepts with respectable
pedigrees. Mars Direct employs ISRU, aerobraking, a
split mission architecture, a tether for artificial gravity,
and a conjunction-class mission planâall concepts that
date from the 1960s or earlier. Mars Direct was influ-
enced by the Case for Mars conferences, the Ride
Report, and the NASA Exploration Office Studies, as
well as ISRU research conducted by Robert Ash,
Benton Clark, and others.
2
Mars Direct has also had staying power since 1990
because one of its authors, engineer Robert Zubrin, has
remained its zealous champion. On April 20, 1990,
Zubrin and co-author David Baker unveiled their plan
to NASA engineers gathered at NASA Marshall.
3
Mars
Direct went public at a National Space Society confer-
ence in Anaheim, California, in June 1990. It first
received widespread attention a week later, after
Zubrin presented it at the Case for Mars IV conference
in Boulder, Colorado.
4
In August 1990 the AIAA magazine Aerospace America
carried a non-technical description of Mars Direct cap-
turing Zubrinâs promotional style.
5
It asked,
Can the United States send humans to Mars
during the present decade? Absolutely. We
have developed vehicle designs and a mission
architecture that can make this possible.
Moreover, the plan we propose is not merely a
âflags and footprintsâ one-shot expedition, but
would put into place immediately an economi-
cal method of Earth-to-Mars transportation,
vehicles for long-range surface exploration,
and functional bases that could evolve into a
mostly self-sufficient Mars settlement.
6
Zubrin and Baker had the first Mars Direct expedi-
tion beginning in December 1996 with the launch of
a Shuttle-derived heavy-lift rocket from the Kennedy
Space Center. The rocket, which Zubrin and Baker
dubbed Ares, would consist of a modified Shuttle
External Tank, two Advanced Solid Rocket Boosters,
and four Space Shuttle Main Engines mounted on the
External Tankâs underside. A liquid hydrogen/liquid
oxygen upper stage and an unpiloted Mars cargo lan-
der covered by a streamlined shroud sat on top of the
External Tank. The 40-ton cargo lander included an
aerobraking heat shield, descent stage, Earth-Return
Vehicle, In-Situ Resource Utilization propellant fac-
tory, 5.8 tons of liquid hydrogen feedstock for propel-
lant manufacture, and a 100-kilowatt nuclear reactor
on a robot truck. The lander was, they wrote, âlight
enough for the booster upper stage to project it
directly onto a six-month transfer orbit to Mars with-
out any refueling or assembly in Earth orbitââhence
the name Mars Direct.
7
The cargo lander would aerobrake in Marsâ atmosphere
and land. After touchdown, the robot truck bearing the
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Humans to Mars: Fifty Years of Mission Planning, 1950â2000
Chapter 10: Design Reference Mission
reactor would trundle away to a natural depression or
one created using explosives. It would lower the reactor
into the craterâthe crater rim would shield the landing
site from radiationâthen would run cables back to the
lander. The reactor would activate, powering compressors
which would draw in Martian air to manufacture propel-
lant. Manufacturing propellants on Mars would help
minimize the weight of propellants that had to be
shipped from Earth.
The propellant factory would use the Sabatier process
first proposed for use on Mars in 1978 by Robert Ash,
William Dowler, and Giulio Varsi. Liquid hydrogen
feedstock would be exposed to Martian carbon dioxide
in the presence of a catalyst, producing 37.7 tons of
methane and water. The methane would be stored and
the water electrolyzed to yield oxygen and more hydro-
gen. The oxygen would then be stored and the hydro-
gen recycled to manufacture more water and methane.
Additional oxygen would be manufactured by decom-
posing carbon dioxide into carbon monoxide and oxy-
gen and venting the carbon monoxide. In a year, the
propellant factory would manufacture 107 tons of
methane and oxygen propellants. The piloted Mars
spacecraft would not be launched until the automated
cargo ship finished manufacturing the required pro-
pellants, thereby reducing risk to crew.
In January 1999âthe next minimum-energy Mars
transfer opportunityâtwo more Ares rockets would
lift off. One would carry a cargo lander identical to
the one already on Mars. The other would carry a
âmanned spacecraft looking somewhat like a giant
hockey puck 27.5 f[ee]t in diameter and 16 f[ee]t tallâ
based on Martin Marietta designs developed for the
NASA Office of Exploration.
8
The top floor would
comprise living quarters for the four-person crew,
while the bottom floor would be stuffed with cargo
and equipment, including a pressurized rover.
Zubrin and Baker estimated the piloted spacecraftâs
weight at 38 tons.
The upper stage would launch the âhockey puckâ
spacecraft on course for Mars and separate, but the
two would remain attached by a 1,500-meter tether.
This assemblage would rotate once per minute to pro-
duce acceleration equal to Martian surface gravity in
the piloted spacecraft. A similar lightweight artificial
gravity concept was proposed by Robert Sohn in
1964. Near Mars the upper stage and tether would be
discarded.
The piloted spacecraft would aerobrake into Mars
orbit, then land near the 1996 cargo lander. No part of
the ship would remain in orbit. Landing the entire crew
on the surface would help minimize risk. Once on Mars,
the Martian atmosphere would provide some radiation
protection, and the crew could use Martian dirt as addi-
tional shielding. They would also experience Martian
gravity. Though only a third as strong as Earthâs grav-
ity, it seemed likely that even that small amount would
be preferable to a long weightless stay in Mars orbit.
As in the SAIC split-sprint plan, the crew would have
to rendezvous at Mars with propellants for their trip
home. This was seen by some as increasing risk. Unlike
the SAIC crew, however, the Mars Direct astronauts
would have options if they could not reach their Earth-
return propellants.
Baker and Zubrin pointed out that the crew had their
rover to drive to the 1996 cargo lander, though ideally
they would land within walking distance. If some gross
error meant they landed more than 600 miles from the
1996 cargo landerâbeyond the range of their roverâ
they could command the cargo lander launched with
them in 1999 to land nearby. It would then manufac-
ture propellant for their return to Earth. If the 1999
cargo lander failed, the Mars Direct astronauts would
have sufficient supplies to hold out until a relief expe-
dition arrived in two years. Assuming that the crew
landed near the 1996 cargo lander as planned, the 1999
cargo lander would set down 500 miles from the first
Mars landing site and begin to make propellants for
the second Mars expedition, which would leave Earth
in 2001.
Eleven of the 107 tons of propellants manufactured by
the 1996 cargo lander would be set aside to power the
pressurized rover. During their 500-day stay on Mars,
the explorers would conduct long traversesâup to 600
miles round-tripâthoroughly characterizing the region
around their landing site. This impressive capability
would maximize science return by allowing the crew to
survey large areas, though with some increased risk. If
the rover broke down, the crew could become stranded
beyond hope of rescue, hundreds of kilometers from base.
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Monographs in Aerospace History
Chapter 10: Design Reference Mission
At the end of the 500-day Mars stay, the ERV engine
would ignite, burning methane and oxygen propellants
manufactured using the Martian atmosphere. The
small ERV spacecraft would use the cargo lander as a
launch pad to perform ascent and direct insertion onto
a trajectory to Earth. After six weightless months in
the cramped ERV, the crew would reenter Earthâs
atmosphere and perform a parachute landing. The
small ERV was considered by many to be a weak link
in the Mars Direct plan.
The 2001 expedition crew would land near the 1999
cargo lander. If all went as planned, the 2001 cargo lan-
der would land 500 miles away. The 2003 crew would
land next to the 2001 cargo lander, while the 2003
cargo lander would touch down 500 miles away for the
2005 expedition, and so on. After several expeditions, a
network of bases would be established. âJust as towns
in the western U.S. grew up around forts and outposts,â
wrote Baker and Zubrin, âfuture [M]artian towns
would spread out from some of these bases. As infor-
mation returns about each site, future missions might
return to the more hospitable ones and larger bases
would begin to form.â
9
SEIâs Last Gasp
In SEIâs last days, the Stafford Synthesis Group report
formed the basis of NASAâs Mars planning. From 1991
to 1993, the Agency performed the First Lunar Outpost
(FLO) study, which took as a point of departure the
lunar elements of the Synthesis Groupâs four architec-
tures. In the summer of 1992, the NASA Headquarters
Exploration Office under Michael Griffin, the successor
to the Office of Exploration first headed by Sally Ride,
launched a NASA-wide study to determine how FLO
might find hardware commonality with a follow-on
Mars expedition, thereby reducing the costs of both
programs.
10
The Mars Exploration Study Team workshop held in
August 1992 produced a plan containing elements of
both Mars Direct and the Synthesis Group Mars plan.
It was briefed to Griffin in September.
11
The May 1993
Mars Exploration Study Team workshop produced a
Mars expedition Design Reference Mission (DRM)
with little overt FLO commonality beyond a common
heavy-lift rocket and outwardly similar vehicles for
lunar and Mars ascent. In fact, the DRM was modeled
on Mars Direct. Robert Zubrin was an advisor to the
Mars Exploration Study Team in late 1992 and 1993.
He briefed Griffin on Mars Direct in June 1992, then
briefed the JSC Exploration Program Office in
October 1992.
12
The Mars Exploration Study Team DRM was report-
ed in a workshop summary and in technical papers
in September and November 1993.
13, 14
It included
the following:
âą
no low-Earth orbit operations or assemblyâ
that is, no reliance on a space station as a Mars
transportation element,
âą
no reliance on a lunar outpost or other lunar
operations,
âą
heavy-lift rocket capable of launching 240 tons
to low-Earth orbit, 100 tons to Mars orbit, and
60 tons to the Martian surface (more than
twice the capability of the Saturn V),
âą
short transit times to and from Mars and long
Mars surface stay times beginning with the
first expedition (conjunction-class missions),
âą
six crewmembers to ensure adequate manpow-
er and skills mix,
âą
early reliance on Mars ISRU to minimize
weight launched to Mars, and
âą
common design for surface and transit habi-
tats to reduce development cost.
The most significant difference between Mars Direct
and the Mars Exploration Study Teamâs DRM was the
division of the Mars Direct ERV functions between two
vehicles. In the Mars Direct plan, the ERV lifted off
from Mars at the end of the surface mission and flew
directly to Earth. In the judgment of many, however,
the Mars Direct ERV was too small to house four astro-
nauts during a six-month return from Mars, let alone
the DRMâs six astronauts.
15
In the DRM, therefore, only
a small Mars Ascent Vehicle (MAV) would rely on
ISRU. The crew would use it to reach Mars orbit at the
end of their surface stay and dock with the orbiting
ERV. The addition of a rendezvous and docking in Mars
orbit was seen by some as increasing risk to crew, but
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Humans to Mars: Fifty Years of Mission Planning, 1950â2000
Chapter 10: Design Reference Mission
there seemed to be little alternative if a realistically
large ERV was to be provided.
The September 2007 Mars transfer opportunity was
used for the study because it would be challenging in
terms of time and energy required for Mars transfer,
not necessarily because an expedition was planned for
that time. The first expedition would begin with launch
of three heavy-lift rockets, each bearing one unmanned
spacecraft and one nuclear propulsion upper stage. The
three spacecraft were the cargo lander, the ERV orbiter,
and an unmanned Habitat lander. They would weigh
between 60 and 75 tons each, a weight estimate con-
sidered more realistic than the 30 to 40 tons quoted in
Mars Direct.
The ERV and Habitat designs were based on a common
crew module design resembling the Mars Direct âhock-
ey puck.â The cargo lander would carry the MAV, ISRU
propellant factory, and hydrogen feedstock, along with
40 tons of cargo, including the pressurized rover. All
would reach Mars during August and September 2008.
The ERV would aerobrake into Mars orbit, while the
cargo lander and Habitat would land on Mars. The
cargo lander would then set about manufacturing 5.7
tons of methane and 20.8 tons of oxygen for the MAV
and a 600-day cache of life-support consumables.
As in Mars Direct, the crew would follow during the next
Mars launch opportunity 26 months later (October-
November 2009), accompanied by unmanned vehicles
supporting the next expedition or providing backup for
those already on Mars. The explorers would land near the
2007 cargo lander and Habitat. The Habitats would
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Monographs in Aerospace History
Chapter 10: Design Reference Mission
Figure 23âNASAâs 1993 Mars mission plan: after landing on
Mars, the automated propellant factory manufactures liquid
methane and liquid oxygen propellants for the conical Mars
Ascent Vehicle it carries on top. (NASA Photo S93-50643)
Figure 24âThe crew Habitat lands near the propellant
factory with empty propellant tanks. Note wheels for mov-
ing the Habitat on the martian surface. (NASA Photo S93-
050645)
Figure 25âMars Base 1: the crew docks its Habitat on the
surface with a second Habitat and begins a 600-day stay.
They use a pressurized rover (left) to explore up to 500 kilo-
meters from base. (NASA Photo S93-45582)
include wheels to allow the explorers to move them
together so they could be linked using a pressurized tun-
nel. The 2007 Habitat would also provide a backup pres-
surized volume if the 2009 Habitat was damaged during
landing and rendered uninhabitable.
The first Mars outpost thus established, the crew
would unpack the pressurized rover from the 2007
cargo lander. During their 600-day stay on Mars, the
crew would carry out several 10-day rover traverses
ranging up to 500 kilometers from the outpost.
In October 2011, the 2009 crew would lift off from Mars
in the 2007 MAV. They would dock in Mars orbit with
the 2007 ERV and fire its twin liquid methane/liquid
oxygen rocket engines to leave Mars orbit for Earth,
retaining the MAV capsule. Near Earth the explorers
would enter the MAV capsule and detach from the
ERV, which would sail past Earth into solar orbit. They
would then reenter Earthâs atmosphere and perform a
parachute landing.
The Mars Exploration Study Team effort was SEIâs last
gasp. Before it was completed, NASA had begun to dis-
mantle its formal Mars exploration planning organiza-
tion. The Headquarters Exploration Office was abol-
ished in late 1992. The JSC Exploration Directorate,
created soon after The 90-Day Studyâs release, was
trimmed back and re-created as the JSC Planetary
Projects Office.
16
As the apparatus for piloted Mars planning within
NASA shrank, automated Mars exploration also suf-
fered a cruel blow. Mars Observer, the first U.S. auto-
mated Mars mission since the Vikings, had left Earth on
25 September 1992. On 21 August 1993, three days
before planned Mars orbit arrival, the spacecraftâs trans-
mitter was switched off as planned to protect it from
shocks during propellant system pressurization. Contact
was never restored. An independent investigation report
released in January 1994 pointed to a propulsion system
rupture as the most probable cause of Mars Observerâs
loss, the first post-launch failure of a U.S. planetary
exploration mission since Surveyor 4 in 1967.
17
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Humans to Mars: Fifty Years of Mission Planning, 1950â2000
Chapter 10: Design Reference Mission
Figure 26âUsing the propellant factory as a launch pad,
the Mars Ascent Vehicle blasts off burning propellants made
from terrestrial hydrogen and Martian atmospheric carbon
dioxide. (NASA Photo S93-050644)
Figure 27âMars Orbit Rendezvous:
The Mars Ascent
Vehicle docks with the Earth Return Vehicle in Mars orbit.
The Earth Return Vehicleâs rocket engines would place the
crew on a six-month low-energy trajectory homeward. (NASA
Photo S93-27626)
NASA almost immediately announced plans to fly Mars
Observerâs science instruments on an inexpensive Mars
orbiter as soon as possible. This marked the genesis of
the Mars Surveyor Program, which aimed to launch
low-cost automated spacecraft to Mars every 26 months,
at each minimum-energy launch opportunity.
18
Refreshed Dreams
In 1994, the JSC Planetary Projects Office, NASAâs de
facto focus for piloted Mars planning following aboli-
tion of the Headquarters Exploration Office, was down-
sized, then abolished. In February it became a branch
of the JSC Solar System Exploration Division, and in
June its remaining personnel were assigned to the
JSC Office of the Curator, where they explored low-
cost options for sending people to the Moon.
19
The
Curatorâs Office managed disposition of Apollo lunar
samples and meteorites, including one meteorite des-
ignated ALH 84001. Even as the Planetary Projects
Office was abolished, ALH 84001 was determined to
have originated on Mars.
On 7 August 1996, NASA, Stanford University, and
McGill University scientists led by NASA scientist
David McKay announced that they had discovered pos-
sible fossil microorganisms in Martian meteorite ALH
84001. In a NASA Headquarters press conference, the
McKay team cited the evidence for past Martian life.
This included the presence of complex carbon com-
pounds resembling those produced when Earth bacte-
ria die, magnetite particles similar to those in some
Earth bacteria, and segmented features on the scale of
some Earth nanobacteria. McKay told journalists,
There is not any one finding that leads us to
believe that this is evidence of past life on Mars.
Rather, it is a combination of many things that
we have found. They include Stanfordâs detec-
tion of an apparently unique pattern of organic
molecules, carbon compounds that are the basis
of life. We also found several unusual mineral
phases that are known products of primitive
microorganisms on Earth. Structures that could
be microscopic fossils seem to support all of this.
The relationship of these things in terms of
locationâwithin a few hundred-thousandths of
an inch of each otherâis the most compelling
evidence.
20
According to their analysis, the 1.9-kilogram rock
soaked in carbonate-rich water containing the possible
microorganisms 3.6 billion years ago. It lay in the
Martian crust, shocked by the occasional local
upheaval, until an asteroid impact blasted it off Mars
16 million years ago. After orbiting the Sun several mil-
lion times, ALH 84001 landed in Antarctica 13,000
years ago, where it was collected on 27 December 1984
in the Allan Hills ice field.
21
The McKay teamâs discovery generated unprecedented
public enthusiasm for Mars, which in turn provided the
catalyst for reestablishment of the JSC Exploration
Office in November 1996. The new office, managed by
Doug Cooke, was reconstituted as part of the Advanced
Development Office in the JSC Engineering
Directorate.
22
Mars planners dusted off the 1993 DRM
to serve as the point of departure for new planning.
At the same time, NASA Headquarters took an impor-
tant step toward eventual piloted Mars exploration. On
7 November 1996, Associate Administrator for Space
Flight Wilbur Trafton, Associate Administrator for Space
Science Wesley Huntress, and Associate Administrator
for Life and Microgravity Sciences and Applications
Arnauld Nicogossian signed a joint memorandum call-
ing for NASAâs Human Exploration and Development of
Space (HEDS) Enterprise and Space Science Enterprise
to work together toward landing humans on Mars.
They told Jet Propulsion Laboratory director Edward
Stone and JSC director George Abbey that â[r]ecent
developments regarding Mars and the growing maturi-
ty of related programs lead us to believe that this is the
right time to fully integrate several areas of robotic and
human Mars exploration study and planning.â
23
The
Associate Administrators then gave Stone and Abbey
until 1 February 1997, to produce âa proposal that
NASA can bring forward, after successful deployment
of the International Space Station, for human explo-
ration missions beginning sometime in the second
decade of the next [21st] century.â
24
Trafton, Huntress, and Nicogossian also asked for âa
credible approach to achieving affordable human Mars
exploration missions.â They defined âa credible costâ as
âthe amount currently spent by NASA on the
International Space Stationââthat is, less than $2 bil-
lion annually. This was a dramatic reduction over the
$15 billion per year proposed in the excised cost section
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Monographs in Aerospace History
Chapter 10: Design Reference Mission
of The 90-Day Study. They asked that Stone and Abbey
identify âtechnology investments and developments
that could dramatically decrease the cost of human and
robotic missions.â
25
In March 1997, the HEDS and Space Science
Enterprises agreed that the 2001 Mars Surveyor lander
should include instruments and technology experiments
supporting piloted Mars exploration. Among the planned
experiments was a compact system for testing ISRU
propellant manufacture on Mars. In a press conference,
Huntress called it âthe first time since the 1960sâ that
âNASAâs space science and human space flight programs
are cooperating directly on the exploration of another
planetary body.â Trafton called the joint effort âa sign
that NASA is acquiring the information that will be
needed for a national decision, perhaps in a decade or so,
on whether or not to send humans to Mars.â
26
In addition to stating that NASAâs robotic program
would complement its piloted Mars flight planning
efforts, the joint memorandum showed that, at a high
managerial level, NASA had not abandoned its plans to
eventually send people to Mars despite SEIâs collapse.
There was no firm timetable for accomplishing the
piloted Mars mission and no Presidential declaration.
Instead, there was a new philosophyâcontinuing low-
level, low-cost planning, much of it in-house, and low-
level Earth-based technology research accompanied by
efforts to use the existing low-cost robotic exploration
program to answer questions relevant to piloted explo-
ration. In short, the Agency accepted publicly for the
first time that it might eventually send people to Mars
without recourse to a new large programâwithout a
new Space Exploration Initiative or Apollo program.
This philosophy continues to guide NASA Mars plan-
ning at the time of this writing (mid-2000).
Success or failure in the automated Mars program thus
became success or failure for piloted Mars planners.
The joint human-robotic Mars effort received a boost on 4
July 1997, when Mars Pathfinder successfully landed at
Ares Vallis, one of the large outwash channels first spot-
ted by Mariner 9 in 1971 and 1972. Pathfinder, the first
U.S. Mars lander since the Vikings, dropped to the rock-
strewn surface and bounced to a stop on airbags, then
opened petals to right itself and expose instruments and
solar cells. The technique was similar to the one the
Soviets employed to land robots on the Moon in the 1960s
and on Mars in the 1970s. The Sojourner roverâthe first
automated rover to operate on another world since the
Soviet Unionâs Lunokhod 2 explored the Moon in 1972â
crawled off its perch on one of Pathfinderâs petals and
crept about the landing area analyzing rock and dirt com-
position. Sojourner and Pathfinderâthe latter renamed
the Sagan Memorial Stationâsuccessfully completed
their primary mission on 3 August.
As Mars Pathfinder bounced to a successful landing in
Ares Vallis, the glossy report Human Exploration of
Mars: The Reference Mission of the NASA Mars
Exploration Study Team rolled off the presses.
27
In addi-
tion to a detailed description of the 1993 DRM, the July
1997 document contained general recommendations on
the conduct of a piloted Mars program based on experi-
ence gained through SEI and the Space Station program.
The report recommended that NASA set up âa Mars
Program Office . . . early in the process.â It also pro-
posed to avoid Space Stationâs redesigns and delays by
establishing âa formal philosophical and budgetary
agreement . . . as to the objectives and requirements
imposed on the mission before development is initiated,
and to agree to fund the project through to completion.â
Finally, taking into account the McKay teamâs discov-
ery, it called for âadequate and acceptable human quar-
antine and sample handling protocols early in the Mars
exploration programâ to protect Earth and Mars from
possible biological contamination.
28
The JSC Exploration Office called its report âanother
chapter in the ongoing process of melding new and
existing technologies, practical operations, fiscal reali-
ty, and common sense into a feasible and viable human
mission to Mars,â adding that âthis is not the last chap-
ter in the process, but [it] marks a snapshot that will
be added to and improved upon by others in the
future.â
29
In fact, by the time the report saw print, the
next chapter was nearly complete.
Scrubbing the DRM
Subsequent DRM evolution focused on minimizing
spacecraft weight in an effort to reduce estimated
mission cost. The slang term engineers used to
describe this process was âscrubbing.â The 1997
âscrubbedâ DRM went public in August 1997.
30
It min-
imized mass by reducing common Habitat diameter;
combining the functions of the pressure hull, aero-
95
Humans to Mars: Fifty Years of Mission Planning, 1950â2000
Chapter 10: Design Reference Mission
96
Monographs in Aerospace History
brake heat shield, and Earth launch shroud; and
employing lightweight composite structures. The
nuclear stages for injecting the spacecraft toward
Mars would be launched into Earth orbit without
spacecraft attached, then docked with the spacecraft
in Earth orbit. These steps and others allowed plan-
ners to eliminate the 1993 DRMâs large heavy-lift
rocket, potentially the costliest mission element.
To place the first crew on Mars, the 1997 DRM would
require eight launches of a Shuttle-derived rocket ca-
pable of boosting 85 tons into Earth orbit. In the first
launch opportunity, six of these rockets would launch
payloadsâthree nuclear propulsion stages and three
Mars spacecraft (cargo lander, ERV, and unpiloted
Habitat). Each spacecraft would dock with its nuclear
stage in Earth orbit, then launch toward Mars. In the
second launch opportunity, 26 months later, six more
Shuttle-derived rockets would launch three nuclear
stages and three spacecraft, including a Habitat lander
containing the crew. The spacecraft would dock with their
nuclear stages and launch toward Mars. The rest of the
mission plan closely resembled the 1993 DRM. To accom-
plish the first expedition, the 1997 DRM would launch
303 tons to Marsâ75 tons less than the 1993 DRM.
The new DRM was on the street, and a few weeks later,
a new automated spacecraft was orbiting Mars. On 11
September 1997, the Mars Global Surveyor orbiter, the
first spacecraft in the Mars Surveyor Program, arrived
in an elliptical Mars orbit after a 10-month flight. Mars
Global Surveyor carried backups of instruments lost
with Mars Observer in 1993. It commenced a series of
passes through Marsâ upper atmosphere to reach a
lower, more circular Mars orbit without using propel-
lants. A damaged solar array threatened to collapse
under the pressure of atmospheric drag, however, so
the aerocapture maneuvers had to be extended over a
year. Nevertheless, the spacecraft turned its instru-
ments toward Mars and began initial observations.
Defining the Surface Mission
As Mars planners sought to minimize spacecraft
weight, it became clear that they would require more
data on the missionâs Mars surface payload. Planners
historically have spent little time detailing what astro-
nauts would do once they landed on Mars. To begin the
process of better defining the 500-to-600-day Mars sur-
face mission, veteran Moon and Mars planner Michael
Chapter 10: Design Reference Mission
Figure 29âNuclear stages in NASAâs 1997 Mars plan
included engines (left) based on revived 1960s NERVA
technology. (NASA Photo S97-07843)
Figure 28âNASAâs 1997 Mars plan proposed to reduce
weight by using an aerobrake integrated with the spacecraft
hull and nuclear rockets. These steps would help eliminate
need for a heavy-lift rocket, permitting a cheaper Shuttle-
derived launch system. (NASA Photo S97-07844)
97
Humans to Mars: Fifty Years of Mission Planning, 1950â2000
Duke chaired a workshop held at the Lunar and
Planetary Institute in Houston on 4-5 October 1997.
31
Workshop participants divided into two working
groups. The Science and Resources group based its dis-
cussions on a âthree-pronged approachâ to Mars explo-
ration. Mars explorers would seek evidence of life or its
precursors and attempt to understand Mars climate
history. They would also act as prospectors, seeking
water, minerals, energy, and other resources for sup-
porting future Mars settlements. This three-pronged
science approach also guided the automated Mars
Surveyor program.
32
The Living and Working on Mars group looked at
chores the crew would need to perform during their
Mars stay. These included initial base setup, such as
deploying an inflatable greenhouse, and base main-
tenance, such as ridding air filters of ever-present
ultra-fine Martian dust. Astronauts on Mars would
also harvest crops, service their space suits, and
perform less mundane tasks such as exploring the
surface in the pressurized rover and drilling deep in
search of Martian microorganisms that might hide
far beneath the surface.
The workshop recommended that âa process and pro-
gram be put into place whereby a wide range of people
could contribute to the thought process.â The report
urged that students in particular be involved, because
âtheir representatives will be the ones who are actual-
ly to do this exploration.â
33
A New Concept
Meanwhile, engineers at NASA Lewis studied using
solar-electric propulsion in the DRM to further reduce
the amount of weight that would have to be launched
into orbit. In January 1999, they proposed a novel con-
cept using a Solar-Electric Transfer Vehicle (SETV)
which never left Earth orbit, but which provided most
of the energy needed to launch the Mars vehicles from
Earth orbit toward Mars.
34
The 1997 DRM required eight Shuttle-derived rockets
for the first Mars expedition. By contrast, the Lewis
solar-electric DRM required only five rockets. Removal
of the backup Habitat landerâa decision taken by
Mars planners in the JSC Exploration Program
Officeâeliminated two heavy-lift rockets. Replacing
the four nuclear stages used to leave Earth in the 1993
and 1997 DRMs with the SETV and three small
expendable chemical stages eliminated one more. This
substitution also eliminated the cost of developing a
nuclear rocket engine and the potential political
headaches of launching nuclear payloads.
The Lewis team envisioned a self-erecting SETV
weighing 123 tons and measuring 194.6 meters across
its thin-film solar arrays. The arrays would provide
electricity to two sets of Stationary Plasma Thrusters
(SPTs), also known as TAL (Thruster with Anode
Layer) or Hall thrusters, an electric propulsion tech-
nology pioneered by the Russians.
The SETV would need months to complete large orbit
changes. Because of this, it would spend considerable
time crossing through Earthâs Van Allen Radiation
Belts. This meant that the Lewis DRM vehicles would
require radiation-hardened systems. The authors
assumed that the SETV would be good for two missions
beyond the Van Allen belts before radiation, tempera-
ture extremes, meteoroid impacts, and ultraviolet light
seriously degraded its solar arrays.
Chapter 10: Design Reference Mission
Figure 30âIn 1998, NASA Lewis Research Center proposed
a reusable Solar-Electric Transfer Vehicle (SETV) and clever
use of orbital mechanics to reduce Mars expedition mass.
SETVâs solar panel spars would inflate in orbit, spreading
âwingsâ of solar cell fabric. (NASA Photo S99-03585)
The SETVâs first mission would place one unpiloted
cargo vehicle and one unpiloted ERV, each with a small
chemical rocket stage, into High-Energy Elliptical
Parking Orbit (HEEPO) around the Earth. The SETV
would start in a nearly circular low-Earth orbit and
raise its apogee by operating its SPT thrusters only at
perigee. It would need from six to twelve months to
raise its apogee to the proper HEEPO for Earth-Mars
transfer. The final HEEPO apogee would be more than
40,000 kilometers, making it very lightly bound by
Earthâs gravity.
When Earth, Mars, and the plane of the HEEPO were
properly aligned for Earth-Mars crossing, the SETV
would release the cargo lander, ERV, and small chemi-
cal stages. At next perigee the chemical stages would
ignite, pushing the spacecraft out of the HEEPO on a
path that would intersect Mars six months later. After
releasing the chemical stages and spacecraft, the SETV
would point its SPTs in its direction of motion and
operate them at perigee to return to a circular low-
Earth orbit.
The SETVâs second mission would place one Habitat
lander with a small chemical stage into HEEPO.
Because the climb to HEEPO again would require up to
twelve months and long periods inside the Van Allen
Radiation Belts, the Habitat lander would remain
unpiloted until just before Earth orbit departure. As
the SETV climbed toward planned final HEEPO
apogee, a small, chemical-propellant âtaxiâ carrying the
Mars crew would set out in pursuit. The crew would
transfer to the Habitat lander, cast off the taxi, then
separate the Habitat lander and chemical stage from
the SETV. At the next perigee, the chemical stage
would ignite to place the first expedition crew on course
for Mars. The remainder of the first Mars expedition
would occur as described in the 1997 scrubbed DRM,
except for the absence of a backup Habitat lander.
In February 1999, soon after the Lewis team made
public their variation on the 1997 DRM, Mars Global
Surveyor achieved its nominal mapping orbit. At this
writing, exploration and data interpretation are on-
going, but it is already clear that the spacecraft is rev-
olutionizing our understanding of Mars. By mid-2000,
its instruments had detected evidence that Mars once
had a strong planetary magnetic field, a finding
potentially important for the early development of
Martian life; that Marsâ polar regions once knew
extensive glaciers; and that water flowed on Marsâ
surface recently, and perhaps flows occasionally today,
carving gullies in cliffs and crater walls.
Not the Last Chapter
In May 1998, a small team of NASA and contractor
space suit engineers traveled to sites in northern
Arizona where Apollo Moonwalkers had trained three
decades before. They observed and assisted as a veter-
an geologist wearing a space suit performed geological
field work and set out simulated scientific instruments
in Mars-type settingsâfor example, on the rim of
Meteor Crater. The team contained cost by traveling
from Houston to Arizona overland and by reusing a
space suit originally designed for Space Station
Freedom. In addition to gathering data on space suit
mobility to enable design of future Mars space suits,
the exercise permitted veteran space suit engineers
who had participated in the development of the Apollo
lunar space suits to pass on their experience to young
engineers who had been children, or not yet born, when
Americans last walked on an alien world.
35
Michael Duke and the other organizers of the Human
Exploration and Development of Space-University
Partners (HEDS-UP) program had a similar motive.
They sought to involve and inspire the next generation
of Mars planners, who might become the first genera-
tion of Mars explorers. In May 1998, the first HEDS-
UP Annual Forum saw undergraduate and graduate
design teams from seven universities across the United
States present Mars design studies.
36
Twice as many
universities sent enthusiastic students to the 1999
HEDS-UP Annual Forum.
37
In the nearly half-century since von Braun wowed
Americans with visions of Mars flight in Collierâs mag-
azine, our understanding of Mars has steadily
improved. We have progressed from hazy telescopic
views of Mars to pictures on the Internet of Sojourner
rearing up on a flood-tossed Martian boulder. Plans for
piloted Mars exploration have matured in step with our
improved vision. For example, no longer do planners
seek to bring all necessities from Earth, for now it is
known that Mars has useful resources.
98
Monographs in Aerospace History
Chapter 10: Design Reference Mission
99
Humans to Mars: Fifty Years of Mission Planning, 1950â2000
The Mars planning concepts developed in the twilight
years of the second millennium form a launch pad for
Mars plannersâand perhaps Mars explorersâat the
dawn of the third. Current technological trendsâfor
example, increasingly capable miniaturized robots and
direct public engagement in Mars exploration through
the Internetâpromise to reshape Mars planning.
Yet it should be remembered that ISRU, the concept
that dominated Mars planning in the 1990s, dates from
the 1960s and 1970s. This suggests that, in addition to
whatever new revolutions future technological develop-
ment brings, other revolutions might lie buried in the
historical archives awaiting the careful and imagina-
tive researcher. Further, this suggests that Mars plan-
ners should carefully preserve their work lest they
deprive future planners of useful concepts.
Young people now looking to Mars, such as the student
participants in the HEDS-UP program, should not have
to waste their time reinventing old concepts. They
should instead be able to study the old concepts and
build new ones upon them. They should also be able to
study the political and social settings of the old con-
cepts, so that they might better navigate the âillogicalâ
pitfalls that can bring down a technically logical Mars
plan. Providing the next generation with the history of
Mars planning helps hasten the day when humans will
leave bootprints on the dusty red dunes of Mars.
Chapter 10: Design Reference Mission
101
Humans to Mars: Fifty Years of Mission Planning, 1950â2000
AAP
Apollo Applications Program
AAS
American Astronautical Society
ABMA
Army Ballistic Missile Agency
AEC
Atomic Energy Commission
AIAA
American Institute of Astronautics and Aeronautics
CIA
Central Intelligence Agency
CM
Command Module
CPS
Chemical Propulsion Stage
CSM
Command and Service Module
DRM
Design Reference Mission
EMPIRE
Early Manned Planetary-Interplanetary Roundtrip Expeditions
EOR
Earth-Orbit Rendezvous
ERV Earth-Return
Vehicle
ET
External Tank
FLEM
Flyby-Landing Excursion Mode
FLO
First Lunar Outpost
FY
Fiscal Year
GNP
Gross National Product
HEDS
Human Exploration and Development Space
HEDS-UP
Human Exploration and Development SpaceâUniversity Partners
HEEPO
High-Energy Elliptical Parking Orbit
IPP
Integrated Program Plan
ISRU
In-Situ Resource Utilization
ISV
Interplanetary Shuttle Vehicle
JAG
Joint Action Group
JPL
Jet Propulsion Laboratory
JSC
Johnson Space Center
KSC
Kennedy Space Center
LANL
Los Alamos National Laboratory
LLNL
Lawrence Livermore National Laboratory
LOR
Lunar-Orbit Rendezvous
LSS
Life Support Section
M
Maneuver
MAV
Mars Ascent Vehicle
MEM
Mars Excursion Module
MEV
Mars Exploration Vehicle, Mars Excursion Vehicle
MMM
Manned Mars Mission
MOR
Mars-Orbit Rendezvous
MSC
Manned Spacecraft Center
MSSR
Mars Surface Sample Return
NACA
National Advisory Committee for Aeronautics
NAR
North American Rockwell
NASA
National Aeronautics and Space Administration
NCOS
National Commission on Space
NERVA
Nuclear Engine for Rocket Vehicle Application
NRC
National Research Council
NRDS
Nuclear Rocket Development Station
OMB
Office of Management and Budget
OMS
Orbiter Maneuvering System
Acronyms
102
Monographs in Aerospace History
OMSF
Office of Manned Space Flight
OTV
Orbital Transfer Vehicle
PH-D
Phobos-Deimos
PM
Propulsion Module
PMRG
Planetary Missions Requirements Group
PPM
Primary Propulsion Module
PSAC
Presidentâs Science Advisory Committee
REM
Roentgen Equivalent Man
RIFT Reactor-In-Flight
Test
SAIC
Science Applications International Corporation
SEI
Space Exploration Initiative
SETV
Solar-Electric Transfer Vehicle
SM
Service Module
SNPO
Space Nuclear Propulsion Office
SOC
Space Operations Center
SPT
Stationary Plasma Thrusters
SRB
Solid Rocket Booster
SSME
Space Shuttle Main Engine
STG
Space Task Group
STS
Space Transportation System
TAL
Thruster with Anode Layer
UMPIRE
Unfavorable Manned Planetary-Interplanetary Roundtrip Expeditions
WGER
Working Group on Extraterrestrial Resources
Acronyms
103
Humans to Mars: Fifty Years of Mission Planning, 1950â2000
Preface
1.
Edward Ezell, âMan on Mars: The Mission That NASA Did Not Flyâ (paper presented at the American
Association for the Advancement of Science Annual Meeting, Houston, Texas, 3-8 January 1979), p. 24.
2.
Readers seeking additional information on Mars planning are directed to the authorâs Web site Romance to
Reality (http://members.aol.com/dsfportree/explore.htm), which contains over 250 annotations of Moon and
Mars planning documents, with more added regularly.
Chapter 1
1.
Wernher von Braun with Cornelius Ryan, âCan We Get to Mars?â Collierâs (30 April 1954), p. 23.
2.
Frederick Ordway and Mitchell Sharpe, The Rocket Team (New York: Thomas Y. Crowell, 1979), p. 408.
3.
Wernher von Braun, The Mars Project (Urbana, IL: University of Illinois Press, 1962).
4.
Ibid., p. 3.
5.
Ibid., p. 75.
6.
Louise Crossley, Explore Antarctica (Cambridge, England: Cambridge University Press, 1995), p. 40.
7.
Fred Whipple and Wernher von Braun, âMan on the Moon: The Exploration,â Collierâs (25 October 1952),
p. 44.
8.
Wernher von Braun, âCrossing the Last Frontier,â Collierâs (22 March 1952): 24-29, 72.
9.
Wernher von Braun, âMan on the Moon: The Journey,â Collierâs (18 October 1952): 52-60; Whipple and von
Braun, âMan on the Moon: The Exploration,â pp. 38-48.
10.
Von Braun with Ryan, âCan We Get to Mars?â pp. 22-28.
11.
Ibid., pp. 26-27.
12.
Willy Ley and Wernher von Braun, The Exploration of Mars (New York: Viking Press, 1956).
13.
Ibid., p. 85.
14.
Ibid., p. 98.
15.
Ibid., p. 157.
Chapter 2
1.
John F. Kennedy, âExcerpts from âUrgent National Needs,â â Speech to a Joint Session of Congress, 25 May
1961, in John Logsdon, gen. ed., with Linda Lear, Janelle Warren-Findlay, Ray Williamson, and Dwayne
Day, Exploring the Unknown: Selected Documents in the History of the U.S. Civil Space Program, Volume I:
Organizing for Exploration (Washington, DC: NASA SP-4407, 1995), pp. 453-54.
Endnotes
Endnotes
104
Monographs in Aerospace History
2.
Robert Merrifield, âA Historical Note on the Genesis of Manned Interplanetary Flight,â AAS Preprint 69-
501 (paper presented at the AAS 15th Annual Meeting, 17-20 June 1969), p. 7.
3.
David S. F. Portree, NASAâs Origins and the Dawn of the Space Age (Washington, DC: NASA Monographs
in Aerospace History #10, 1998), pp. 8-11.
4.
Ezell, âMan on Mars,â pp. 5-6; see also Merrifield, âA Historical Note,â p. 8.
5.
S. C. Himmel, J. F. Dugan, R. W. Luidens, and R. J. Weber, âA Study of Manned Nuclear-Rocket Missions to
Mars,â IAS Paper No. 61-49 (paper presented at the 29th Annual Meeting of the Institute of Aerospace
Sciences, 23-25 January 1961), p. 2.
6.
Ibid., p. 5.
7.
Ibid., p. 18.
8.
Von Braun with Ryan, âCan We Get to Mars?â p. 24.
9.
Himmel, et al., âA Study of Manned Nuclear-Rocket Missions to Mars,â p. 35.
10.
Ibid., p. 24.
11.
Ibid., p. 30.
12.
Ibid., p. 33-34.
13.
John Logsdon, The Decision to Go to the Moon: Project Apollo and the National Interest (Cambridge, MA:
MIT Press, 1970), pp. 111-12.
14.
Office of Program Planning and Evaluation, âThe Long Range Plan of the National Aeronautics and
Space Administration,â 16 December 1959, Logsdon, gen. ed., Exploring the Unknown, Vol. I, p. 404.
15.
Ezell, âMan on Mars,â p. 8.
16.
Ernst Stuhlinger, âPossibilities of Electrical Space Ship Propulsion,â Friedrich Hecht, editor, Bericht ĂŒber
de V Internationalen Astronautischen Kongress (Osterreichen Gesellschaft fĂŒr Weltraumforschung, Vienna,
Austria, 1955).
17.
âMars and Beyond,â The Wonderful World of Disney television program, 4 December 1957.
18.
Portree, NASAâs Origins, p. 12.
19.
Ernst Stuhlinger and Joseph King, âConcept for a Manned Mars Expedition with Electrically Propelled
Vehicles,â Progress in Astronautics, Vol. 9 (San Diego: Univelt, Inc., 1963), pp. 647-64.
20.
Ibid., p. 658.
21.
Ibid., p. 648.
Endnotes
105
Humans to Mars: Fifty Years of Mission Planning, 1950â2000
22.
James Hansen, Enchanted Rendezvous: John C. Houbolt and the Genesis of the Lunar-Orbit Rendezvous
Concept (Washington, DC: NASA Monographs in Aerospace History #4, 1995).
Chapter 3
1.
Robert Sohn, âSummary of Manned Mars Mission Study,â Proceeding of the Symposium on Manned
Planetary Missions: 1963/1964 Status (Mountain View, CA: NASA TM X-53049, 1964), p. 151.
2.
T. A. Heppenheimer, The Space Shuttle Decision: NASAâs Search for a Reusable Space Vehicle (Washington,
DC: NASA, 1999), pp. 60-61.
3.
âOne-Year Exploration-Trip Earth-Mars-Venus-Earth,â Gaetano A. Crocco, Rendiconti del VII Congresso
Internanzionale Astronautico, Associazione Italiana Razzi (paper presented at the Seventh Congress of
the International Astronautical Federation, Rome, Italy, 1956), pp. 227-252.
4.
Ibid., p. 239.
5.
Maxime Faget and Paul Purser, âFrom Mercury to Mars,â Aeronautics & Aerospace Engineering (February
1963): 27.
6.
Ibid., p. 24.
7.
Aeronutronic Division, Ford Motor Company, EMPIRE, A Study of Early Manned Interplanetary
Expeditions (Huntsville, AL: NASA CR-51709, 21 December 1962).
8.
Lockheed Missiles & Space Company, Manned Interplanetary Mission Study (Lockheed Missiles and
Space Company, March 1963).
9.
General Dynamics Astronautics, A Study of Early Manned Interplanetary Missions Final Summary Report
(San Diego, CA, General Dynamics Astronautics, 31 January 1963).
10.
Aeronutronic, p. 1-2.
11.
Lockheed, p. xx.
12.
General Dynamics, p. 8-2.
13.
Ibid., pp. 8-92 - 8-122.
14.
Ibid., pp. 8-119 - 8-122.
15.
David Hammock and Bruce Jackson, âVehicle Design for Mars Landing and Return to Mars Orbit,â
George Morgenthaler, editor, Exploration of Mars (San Diego, CA: Univelt, Inc., 1964), pp. 174-95.
16.
Raymond Watts, âManned Exploration of Mars?â Sky & Telescope (August 1963): 63-67, 84.
17.
Hammock and Jackson, âVehicle Design for Mars Landing,â p. 175.
Endnotes
106
Monographs in Aerospace History
18.
Franklin Dixon, âSummary Presentation: Study of a Manned Mars Excursion Module,â Proceeding of the
Symposium on Manned Planetary Missions: 1963/1964 Status (Huntsville, AL: NASA TM X-53140, 1964),
pp. 443-523.
19.
Ibid., p. 449.
20.
Ibid., p. 479.
21.
Ibid., p. 449.
22.
Ibid., p. 479.
23.
J. N. Smith, Manned Mars Missions in the Unfavorable (1975-1985) Time Period: Executive Summary
Report (Huntsville, AL: NASA TM X-53140, 1964).
24.
Ibid., p. 7.
25.
Ibid., pp. 11-12.
26.
Sohn, âSummary of Manned Mars Mission Study,â pp. 149-219.
27.
Ibid., p. 156.
28.
Ibid., p. 170.
29.
Ibid., p. 165-166.
30.
âPart 17: Panel Discussion,â Proceeding of the Symposium on Manned Planetary Missions: 1963/1964
Status (Huntsville, AL: NASA TM X-53140, 1964), pp. 748-749.
31.
Ibid., p. 751.
32.
Ibid.
33.
âFuture Efforts to Stress Apollo Hardware,â Aviation Week & Space Technology (16 November 1964): 48.
34.
Ezell, âMan on Mars,â p. 13.
35.
Ibid., p. 12.
36.
Harry Ruppe, Manned Planetary Reconnaissance Mission Study: Venus/Mars Flyby (Huntsville, AL:
NASA TM X-53205, 1965).
37.
Ibid., p. 53.
38.
Ibid., p. 7.
39.
Ibid., p. 8.
Endnotes
107
Humans to Mars: Fifty Years of Mission Planning, 1950â2000
Chapter 4
1.
Robert Hotz, âNew Era for NASA,â Aviation Week & Space Technology (7 August 1967): 17.
2.
Samuel Glasstone, The Book of Mars (Washington, DC: NASA SP-179, 1968), pp. 76-91.
3.
William Hartmann and Odell Raper, The New Mars: The Discoveries of Mariner 9 (Washington, DC: NASA
SP-337, 1974), pp. 6-11.
4.
Edward Clinton Ezell and Linda Neumann Ezell, On Mars: Exploration of the Red Planet, 1958-1978
(Washington, DC: NASA 1984), pp. 74-82.
5.
NASA, âA Report from Mariner IV,â NASA Facts 3 (1966): 1.
6.
Ibid., pp. 5-6; Oran Nicks, Summary of Mariner 4 Results (Washington, DC: NASA SP-130), p. 35.
7.
Hal Taylor, âLBJ Wants Post-Apollo Plans,â Missiles and Rockets (4 May 1964); NASA, Summary Report:
Future Programs Task Group, January 1965, Logsdon, gen. ed., Exploring the Unknown, Vol. I, p. 473.
8.
âFuture Effort to Stress Apollo Hardware,â Aviation Week & Space Technology (16 November 1964): 48-51.
9.
âScientists Urge Priority for Mars Missions,â Aviation Week & Space Technology (23 November 1964): 26.
10.
Merrifield, âA Historical Note,â p. 12; Astronautics and Aeronautics 1966 (Washington, DC: NASA SP-
4007), p. 17.
11.
Willard Wilks and Rex Pay, âQuest for Martian Life Re-Emphasized,â Technology Week (6 June 1966): 26-
28.
12.
Ezell and Ezell, On Mars, pp. 102-05.
13.
Associate Administrator, Office of Space Science and Applications to Director, Office of Space Science and
Applications, âManned Planetary Missions Planning Group,â 30 April 1965.
14.
Franklin Dixon, âManned Planetary Mission Studies from 1962 to 1968,â IAA-89-729 (paper presented at
the 40th Congress of the International Astronautical Federation, Malaga, Spain, 7-12 October 1989), p. 9.
15.
Ezell, âMan on Mars,â p. 12.
16.
Merrifield, âA Historical Note,â p. 13.
17.
Planetary JAG, Planetary Exploration Utilizing a Manned Flight System (Washington, DC: NASA, 1966).
18.
For example, see Robert Sohn, âA Chance for an Early Manned Mars Mission,â Astronautics & Aeronautics
(May 1965): 28-33.
19.
Chief, NASA Kennedy Space Center Advanced Programs Office to Distribution, âMinutes of Joint Action
Group Meeting of June 29-30, 1966,â 8 July 1966.
Endnotes
108
Monographs in Aerospace History
20.
R. R. Titus, âFLEMâFlyby-Landing Excursion Mode,â AIAA Paper No. 66-36 (paper presented at the 3rd
AIAA Aerospace Sciences Meeting, New York, New York, 24-26 January 1966).
21.
Edward Gray to H. K. Weidner, F. L. Williams, M. Faget, W. E. Stoney, J. West, J. P. Claybourne, and R.
Hock, TWX, âMeeting to Establish Follow-on Activities Covering the Advanced Manned Planetary, Earth
Orbital, and Lunar Exploration Programs,â 17 November 1966.
22.
Edward Gray to H. K. Weidner, F. L. Williams, J. W. Carter, R. J. Harris, J. P. Claybourne, R. Hock, and R.
J. Cerrato, TWX, âFollow-on Activity for Manned Planetary Program,â 2 December 1966.
23.
John Logsdon, âFrom Apollo to the Space Shuttle: U.S. Space Policy, 1969-1972,â unpublished manuscript,
p. I-43.
24.
âU.S. Space Funding to Grow Moderately,â Aviation Week & Space Technology (6 March 1967): 126.
25.
William Normyle, âPost-Apollo Program Potential Emerging,â Aviation Week & Space Technology (6 March
1967): 126.
26.
Presidentâs Science Advisory Committee, The Space Program in the Post-Apollo Period (Washington, DC:
The White House, February 1967).
27.
Ibid., p. 18.
28.
âScience Advisors Urge Balanced Program,â Aviation Week & Space Technology (6 March 1967): 135.
29.
William Normyle, âManned Mars Flights Studied for the 1970s,â Aviation Week & Space Technology (27
March 1967): 63.
30.
Merrifield, âA Historical Note,â p. 13.
31.
Normyle, âManned Mars Flights Studied,â p. 62-63; Edward Gray and Franklin Dixon, âManned
Expeditions to Mars and Venus,â Eric Burgess, editor, Voyage to the Planets (San Diego, CA: Univelt, Inc.,
1967), pp. 107-35.
32.
âU.S. Space Funding Set to Grow Moderately,â pp. 123-24.
33.
âHouse Unit Trims NASA Budget, Fight Pledged for Further Slashes,â Aviation Week & Space Technology
(22 May 1967): 24.
34.
âSpace Funds Cut Deeply by House, Senate,â Aviation Week & Space Technology (3 July 1967): 28.
35.
âConferees Vote Space Cut,â Aviation Week & Space Technology (7 August 1967): 24.
36.
William Normyle, âSmall Hope Seen to Restore Space Funds,â Aviation Week & Space Technology (10 July
1967): 38.
37.
Katherine Johnsen, âWebb Refuses to Choose Program for Cuts,â Aviation Week & Space Technology (31
July 1967): 20.
Endnotes
109
Humans to Mars: Fifty Years of Mission Planning, 1950â2000
38.
Hotz, âNew Era for NASA,â p. 17.
39.
Spacecraft Engineering Branch, Apollo-based Venus/Mars Flybys (Houston: NASA MSC, September 1967).
40.
Contracting Officer to Prospective Contractors, âPlanetary Surface Sample Return Probe Study for
Manned Mars/Venus Reconnaissance/Retrieval Missions,â Request for Proposal No. BG721-28-7-528P, 3
August 1967.
41.
Irving Stone, âManned Planetary Vehicle Study Proposed,â Aviation Week & Space Technology (2 October
1967): 87.
42.
William Normyle, âPriority Shift Blocks Space Plans,â Aviation Week & Space Technology (11 September
1967): 27.
43.
Ezell and Ezell, On Mars, p. 118.
44.
âWhite House Stand Blocks NASA Budget Restoration,â Aviation Week & Space Technology (28 August
1967): 32.
45.
Ezell and Ezell, On Mars, p. 142.
Chapter 5
1.
NASA, âOutline of NASA Presentation to Space Task Group, August 4, 1969â (28 July 1969), p. 20.
2.
Wernher von Braun, âThe Next 20 Years of Interplanetary Exploration,â Astronautics & Aeronautics
(November 1965): 24.
3.
NASA, Astronautics and Aeronautics 1967 (Washington, DC: NASA SP-4008), pp. 339-41.
4.
James Dewar, âAtomic Energy: The Rosetta Stone of Space Flight,â Journal of the British Interplanetary
Society (May 1994): 200.
5.
Ibid., p. 202.
6.
John Kennedy, âExcerpts from âUrgent National Needs,ââ Logsdon, gen. ed., Exploring the Unknown, Vol. I,
p. 454.
7.
Dewar, âAtomic Energy,â p. 203-04.
8.
Raymond Watts, âManned Exploration of Mars?â Sky & Telescope (August 1963): 64.
9.
William House, âThe Development of Nuclear Rocket Propulsion in the United States,â Journal of the
British Interplanetary Society 19, No. 8 (March-April 1964): 317-18.
10.
Boeing Aerospace Group, Integrated Manned Interplanetary Spacecraft Concept Definition, Vol. 1,
Summary (Seattle, Washington: NASA CR-66558, January 1968).
Endnotes
110
Monographs in Aerospace History
11.
North American Rockwell Corporation Space Division, Definition of Experimental Tests for a Manned
Mars Excursion Module: Final Report, Vol. 1, Summary (SD 67-755-1, 12 January 1968).
12.
Arthur Hill, âApollo Shape Dominates NAR Manned Mars Study,â Aerospace Technology (6 May 1968): pp.
26.
13.
âCost of Tet,â Aviation Week & Space Technology (27 May 1968): 25.
14.
âCongressional Critics Aim to Cut NASA Budget to $4-Billion Level,â Aviation Week & Space Technology
(12 February 1968): 22.
15.
Katherine Johnsen, âNASA Gears for $4-Billion Fund Limit,â Aviation Week & Space Technology (27 May
1968): 30.
16.
âWebb Urges Full $4-Billion NASA Fund,â Aviation Week & Space Technology (1 July 1968): 22.
17.
Administrator to Associate Administrator for Manned Space Flight, âTermination of the Contract for
Procurement of Long Lead Time Items for Vehicles 516 and 517,â Logsdon, gen. ed., Exploring the
Unknown, Vol. I, pp. 494-95.
18.
âWork on Future Saturn Launchers Halted,â Aviation Week & Space Technology (12 August 1968): 30.
19.
NASA, Astronautics and Aeronautics 1968 (Washington, DC: NASA SP-4010), pp. 212-13.
20.
NASA, Astronautics and Aeronautics 1968 (Washington, DC: NASA SP-4010), p. 215.
21.
William Normyle, âNASA Plans Five-Year Fund Rise,â Aviation Week & Space Technology (14 October
1968): 16.
22.
Bureau of the Budget, âNational Aeronautics and Space Administration: Highlight Summary,â 30 October
1968, Logsdon, gen. ed., Exploring the Unknown, Vol. I, pp. 497-98.
23.
Courtney Brooks, James Grimwood, and Loyd Swenson, Jr., Chariots for Apollo, A History of Manned
Lunar Spacecraft (Washington, DC: NASA SP-4205, 1979), p. 279.
24.
Ibid., pp. 256-60.
25.
Arthur Schlesinger, Jr., The Almanac of American History (Greenwich, CT: Brompton Books, 1993), p. 581.
26.
âAgainst the Tide,â Aviation Week & Space Technology (17 March 1969): 15.
27.
Heppenheimer, The Space Shuttle Decision, pp. 115-16.
28.
Roger Launius, âThe Waning of the Technocratic Faith: NASA and the Politics of the Space Shuttle
Decision,â Philippe Jung, editor, History of Rocketry and Astronautics, AAS History Series, Volume 21 (San
Diego, CA: Univelt, Inc., 1997), p. 190.
29.
Heppenheimer, The Space Shuttle Decision, p. 127.
Endnotes
111
Humans to Mars: Fifty Years of Mission Planning, 1950â2000
30.
NASA, Astronautics and Aeronautics 1968 (Washington, DC: NASA SP-4010), pp. 215.
31.
Charles Townes, et al., âReport of the Task Force on Space,â 8 January 1969, Logsdon, gen. ed., Exploring
the Unknown, Vol. I, p. 502.
32.
Ibid., p. 505.
33.
Heppenheimer, The Space Shuttle Decision, pp. 121-22.
34.
Dwayne Day, âViewpoint: Paradigm Lost,â Space Policy (August 1995): 156.
35.
Heppenheimer, The Space Shuttle Decision, pp. 127-28.
36.
William Normyle, âNASA Aims at 100-man Station,â Aviation Week & Space Technology (24 February
1969): 16.
37.
Richard Nixon, âMemorandum for the Vice President, the Secretary of Defense, the Acting Administrator,
NASA, and the Science Advisor,â 13 February 1969, Logsdon, gen. ed., Exploring the Unknown, Vol. I, p. 513.
38.
Thomas Paine, âProblems and Opportunities in Manned Space Flight,â Logsdon, gen. ed., Exploring the
Unknown, Vol. I, pp. 513-19.
39.
Logsdon, âFrom Apollo to the Space Shuttle,â pp. III-7 - III-8; Heppenheimer, The Space Shuttle Decision,
pp. 130-31.
40.
NASA, âIntegrated Manned Space Flight Program, 1970-1980â (12 May 1969).
41.
Ibid., p. 2.
42.
Logsdon, âFrom Apollo to the Space Shuttle,â p. IV-50.
43.
Logsdon, âFrom Apollo to the Space Shuttle,â p. IV-40.
44.
NASA, Astronautics and Aeronautics 1969 (Washington, DC: NASA SP-4014), pp. 235-36.
45.
NASA, Astronautics and Aeronautics 1969 (Washington, DC: NASA SP-4014), p. 239.
46.
âWashington Roundup,â Aviation Week & Space Technology (21 July 1969): 15.
47.
NASA, Astronautics and Aeronautics 1969 (Washington, DC: NASA SP-4014), p. 270.
48.
NASA, Astronautics and Aeronautics 1969 (Washington, DC: NASA SP-4014), p. 271.
49.
NASA, âOutline of NASA Presentation to Space Task Group, August 4, 1969â (28 July 1969), p. 20.
50.
Wernher von Braun, âManned Mars Landing Presentation to the Space Task Group,â presentation materials
(4 August 1969).
51.
Ibid., p. 4.
Endnotes
112
Monographs in Aerospace History
52.
Ibid., pp. 22-24.
53.
Ibid., p. 26.
54.
Ibid., p. 35.
55.
Ibid., pp. 41-43.
56.
NASA, âOutline of NASA Presentation,â p. 23.
57.
Robert Seamans, Jr., Secretary of the Air Force, to Spiro Agnew, Vice President, letter, 4 August 1969,
Logsdon, gen. ed., Exploring the Unknown, Vol. I, p. 521-22.
58.
âWashington Roundup,â p. 15.
59.
Logsdon, âFrom Apollo to the Space Shuttle,â p. IV-53.
60.
Ibid.
61.
Ibid., pp. 57-63.
62.
âSpace Manpower,â Aviation Week & Space Technology (11 August 1969): 25.
63.
Robert Hotz, âThe Endless Frontier,â Aviation Week & Space Technology (11 August 1969): 17.
64.
William Normyle, âManned Mission to Mars Opposed,â Aviation Week & Space Technology (18 August
1969): 16.
65.
Ibid., p. 17.
66.
NASA, Americaâs Next Decades in Space: A Report to the Space Task Group (Washington, DC: NASA,
September 1969).
67.
Ibid., p. 7.
68.
Ibid., p. 1.
69.
Space Task Group, The Post-Apollo Space Program: Directions for the Future (Washington, DC: NASA,
September 1969).
70.
Logsdon, gen. ed., Exploring the Unknown, Vol. I, pp. 522-23.
71.
Space Task Group, The Post-Apollo Space Program, pp. ii-iii.
72.
Ibid., p. iv.
73.
Ibid.
74.
Wernher von Braun interview by John Logsdon, referenced in T. A. Heppenheimer, The Space Shuttle
Decision, p. 152.
Endnotes
113
Humans to Mars: Fifty Years of Mission Planning, 1950â2000
75.
Robert Mayo, Director, Bureau of the Budget, âMemorandum for the President, âSpace Task Group
Report,ââ 25 September 1969, Logsdon, gen. ed., Exploring the Unknown, Vol. I, pp. 545-46.
76.
âNASA Budget Faces House-Senate Parley,â Aviation Week & Space Technology (29 September 1969): 19.
77.
George Mueller to John Naugle, 6 October 1969; Morris Jenkins, Manned Exploration Requirements and
Considerations (Houston: NASA, February 1971), pp. iii-iv.
78.
Logsdon, âFrom Apollo to the Space Shuttle,â p. V-22.
79.
âBill of Fare,â Aviation Week & Space Technology (2 February 1970): 11; NASA, Astronautics and
Aeronautics 1970 (Washington, DC: NASA SP-40), pp. 11-12.
80.
âCenters Reviewed,â Aviation Week & Space Technology (19 January 1970): 16.
81.
âSpace in the 1970s,â Aviation Week & Space Technology (9 February 1970): 11.
82.
Schlesinger, p. 586.
83.
âAd Astra per Aspera,â Aviation Week & Space Technology (9 February 1970): 10.
84.
Logsdon, âFrom Apollo to the Space Shuttle,â p. V-40.
85.
Space Science and Technology Panel of the Presidentâs Science Advisory Committee, The Next Decade in
Space (Washington, DC: Executive Office of the President, Office of Science and Technology, March 1970),
pp. 3, 22.
86.
Ibid., p. i.
87.
Ibid., p. 45.
88.
Ibid., p. 4.
89.
Ibid., p. 52.
90.
Launius, âThe Waning of the Technocratic Faith,â p. 185.
91.
Morris Jenkins, Manned Mars Exploration Requirements and Considerations (Houston: NASA, February
1971), p. iv.
92.
Ibid., p. iii.
93.
Ibid., p. 4â14.
94.
Ibid., p. 2â15.
95.
U.S. Congress, Nuclear Rocket Development Program, Joint Hearings before the Committee on
Aeronautical and Space Sciences, United States Senate and the Joint Committee on Atomic Energy, 92nd
Congress of the United States, First Session, 23-24 February 1971, p. 1.
Endnotes
114
Monographs in Aerospace History
96.
Ibid., pp. 13-15.
97.
Ibid., p. 21.
98.
Ibid., p. 34.
99.
Ibid., p. 40.
100. âOMB Limits NASA to $15 Million for NERVA,â Aviation Week & Space Technology (4 October 1971): 20.
101. Launius, âThe Waning of the Technocratic Faith,â pp. 188-89.
102. NASA, Astronautics and Aeronautics 1972, (Washington, DC: NASA SP-4017), pp. 4-5
103. Dewar, âAtomic Energy,â p. 205.
Chapter 6
1.
Benton Clark, âThe Viking ResultsâThe Case for Man on Mars,â AAS 78-156, Richard Johnston, Albert
Naumann, and Clay Fulcher, editors, The Future U.S. Space Program (San Diego: Univelt, Inc., 1978), p. 263.
2.
Hartmann and Raper, The New Mars, pp. 32.
3.
Ray Bradbury, Arthur C. Clarke, Bruce Murray, Carl Sagan, and Walter Sullivan, Mars and the Mind of Man
(New York: Harper and Row, 1973) is an informative and entertaining exploration of changing human per-
ceptions of the planet Mars.
4.
Hartmann and Raper, The New Mars, pp. 94-107.
5.
Andrew Wilson, Solar System Log (New York: Janeâs, 1987), p. 69.
6.
Richard Lewis, âOn the Golden Plains of Mars,â Spaceflight (October 1976): 364.
7.
Richard Lewis, âThe Puzzle of Martian Soil,â Spaceflight (November 1976): 391-95. See also Bevan
French, Mars: The Viking Discoveries (Washington, DC: NASA, 1977), pp. 20-22; Andrew Chaikin, âThe
Case for Life on Mars,â Air & Space Smithsonian (February/March 1991): 63-71; Harold Klein, Norman
Horowitz, and Klaus Biemann, âThe Search for Extant Life on Mars,â Hugh Kieffer, Bruce Jakosky,
Conway Snyder, and Mildred Mathews, editors, Mars, (Tucson: University of Arizona Press, 1992), pp.
1221-33.
8.
Cary Spitzer, editor, Viking Orbiter Views of Mars (Washington, DC: NASA, 1980), pp. 31-32. See also Victor
Baker, Michael Carr, Virginia Gullick, Cameron Williams, and Mark Marley, âChannels and Valley
Networksâ; and Christopher McKay, R. L. Mancinelli, Carol Stoker, and R. A. Wharton, âThe Possibility of Life
on Mars During a Water-Rich Past,â both in Hugh Kieffer, et al., editors, Mars, pp. 493-522 and 1234-45.
9.
Ezell and Ezell, On Mars, pp. 422-23.
10.
NASA, Proceedings of the Seventh Annual Working Group on Extraterrestrial Resources (Washington, DC:
NASA SP-229, 1970), p. iii.
Endnotes
115
Humans to Mars: Fifty Years of Mission Planning, 1950â2000
11.
J. N. Smith, Manned Mars Missions in the Unfavorable (1975-1985) Time Period, pp. 11-12.
12.
Louis Friedman interview by David S. F. Portree, 15 August 1999.
13.
R. L. Ash, W. L. Dowler, and G. Varsi, âFeasibility of Rocket Propellant Production on Mars,â Acta
Astronautica (July-August 1978): 705-24.
14.
Clark, âThe Viking Results,â p. 273.
15.
Ibid., p. 274.
16.
Other examples of Mars ISRU papers in the 1980s include the following: Benton Clark, âThe Chemistry of
the Martian Surface: Resources for the Manned Exploration of Mars,â AAS 81-243, Penelope Boston, edi-
tor, The Case for Mars, (San Diego, CA: Univelt, Inc., 1984), pp. 197-208; G. R. Babb and W. R. Stump, âThe
Effect of Mars Surface and Phobos Propellant Production on Earth Launch Mass,â Michael Duke and Paul
Keaton, editors, Manned Mars Missions: Working Group Papers, Vol. 1 (Huntsville, AL, and Los Alamos, NM:
NASA M002, NASA/LANL, June 1986), pp. 162-175; R. H. Frisbee, âMass and Power Estimates for Mars In-
Situ Propellant Production Systems,â AIAA-87-1900 (papers presented at the AIAA/SAE/ASME/ASEE 23rd
Joint Propulsion Conference, 29 June-2 July 1987); Benton Clark and Donald Pettit, âThe Hydrogen
Peroxide Economy on Mars,â AAS 87-214, Carol Stoker, editor, The Case for Mars III:
Strategies for
ExplorationâGeneral Interest and Overview (San Diego, CA: Univelt, Inc.,1989), pp. 551-57; Robert Ash,
Joseph Werne, and Merry Beth Haywood, âDesign of a Mars Oxygen Processor,â AAS 87-263, Carol Stoker,
editor, The Case for Mars III: Strategies for ExplorationâTechnical (San Diego, CA: Univelt, Inc.,1989), pp.
479-87; Diane L. Galecki, âIn-Situ Propellant Advantages for Fast Transfer to Mars,â AIAA-88-2901 (paper
presented at the AIAA/ASME/SAE/ASEE 24th Joint Propulsion Conference, 11-13 July 1988); Thomas
Meyer and Christopher McKay, âThe Resources of Mars for Human Settlement,â Journal of the British
Interplanetary Society (April 1989): 147-60; J. R. French, âRocket Propellants from Martian Resources,â
Journal of the British Interplanetary Society (April 1989): 167-70.
17.
Louis Friedman interview, 15 August 1999. Friedman founded The Planetary Society with Carl Sagan and
Bruce Murray in 1980.
18.
Robert Ash interview by David S. F. Portree, 29 July 1999. Ash called Friedman âISRUâs godparent.â
Chapter 7
1.
Alcestis Oberg, âThe Grass Roots of the Mars Conference,â AAS 81-225, Penelope Boston, editor, The Case
for Mars (San Diego, CA: Univelt, Inc., 1984), p. ix.
2.
Tim Furniss, Space Shuttle Log (New York: Janeâs, 1986), pp. 15-18, 34-36.
3.
William Stockton and John Noble Wilford, Spaceliner (New York: Times Books, 1981), p. 159.
4.
Oberg, âThe Grass Roots,â p. ix.
5.
Benton Clark interview by David S. F. Portree, 27 August 1999.
6.
S. Fred Singer, âThe PH-D Proposal: A Manned Mission to Phobos and Deimos,â AAS 81-231, Penelope
Boston, editor, The Case for Mars (San Diego, CA: Univelt, Inc., 1984), pp. 39-65.
Endnotes
116
Monographs in Aerospace History
7.
S. Fred Singer, âTo Mars By Way of Its Moons,â Scientific American (March 2000): 56-57.
8.
Space Sciences Department, Manned Lunar, Asteroid and Mars Missions, Visions of Space Flight: Circa 2001
(Schaumburg, IL: Science Applications International Corporation, September 1984).
9.
Louis Friedman, âVisions of 2010,â The Planetary Report (March/April 1985): 5.
10.
Louis Friedman interview by David S. F. Portree, 15 August 1999.
11.
Friedman, âVisions,â pp. 6, 22.
12.
Ibid., p. 22.
13.
âBeggs Calls for Start on Space Station,â Space News Roundup (25 June 1982): 1, 3-4.
14.
Clarke Covington, âThe Role of the Space Operations Center,â presentation materials (28 May 1981).
15.
Dave Alter, âSpace Operations Centerâ (Houston, TX: NASA Johnson Space Center Press Release 82-008, 19
February 1982).
16.
Presidential Papers of the President: Administration of Ronald Reagan, 1985 (Washington, DC: U.S.
Government Printing Office, 1985), p. 90.
17.
Humboldt Mandell, personal communication.
18.
Michael Duke interview by David S. F. Portree, 26 August 1999.
19.
Paul Keaton interview by David. S. F. Portree, 30 August 1999.
20.
R. F. Baillie to R. W. Johnson, âManned Planetary Exploration Action Item from the Wallops Workshopâ
(August 1, 1978); Joseph Loftus, Jr., interview by David S. F. Portree, 15 August 1999.
21.
Keaton interview, 30 August 1999.
22.
Harrison Schmitt, âA Millennium ProjectâMars 2000,â Wendell Mendell, editor, Lunar Bases and Space
Activities of the 21st Century (Houston, TX: Lunar and Planetary Science Institute, 1985), p. 787.
23.
Duke interview, 30 August 1999; Keaton interview, 30 August 1999.
24.
Ibid.
25.
Michael Duke and Paul Keaton, editors, Manned Mars Missions, Working Group Summary Report
(Huntsville, AL, and Los Alamos, NM: NASA M001, NASA/LANL, May 1986); Michael Duke and Paul
Keaton, editors, Manned Mars Missions, Working Group Papers, Vol. 1 and Vol. 2 (Huntsville, AL, and Los
Alamos, NM: NASA M002, NASA/LANL, June 1986).
26.
Charles Cravotta and Melanie DeForth, âSoviet Plans for a Manned Flight to Marsâ (Office of Scientific and
Weapons Research, U.S. Central Intelligence Agency, 2 April 1985), p. 2.
Endnotes
117
Humans to Mars: Fifty Years of Mission Planning, 1959â2000
27.
Ibid.
28.
Ibid., p. 7.
29.
Ibid., p. 8.
30.
Barney Roberts, âConcept for a Manned Mars Flyby,â Manned Mars Missions: Working Group Papers, Vol.
1 (Huntsville, AL, and Los Alamos, NM: NASA M002, NASA/LANL, June 1986), pp. 203-18.
31.
Ibid., pp. 213-15.
32.
Buzz Aldrin, âThe Mars Transit System,â Air & Space Smithsonian (October/November 1990): 47.
33.
Charles Rall and Walter Hollister, âFree-fall Periodic Orbits Connecting Earth and Mars,â AIAA No. 71-92
(paper presented at the American Institute of Aeronautics and Astronautics 9th Aerospace Sciences
Meeting, New York, New York, 25-27 January 1971). Cycler proponent Buzz Aldrin was one of Hollisterâs
students at MIT before he became a NASA astronaut.
34.
S. M. Welch and C. R. Stoker, editors, The Case for Mars: Concept Development for a Mars Research Station
(Boulder, CO: Boulder Center for Science Policy, 10 April 1986).
35.
Thomas Paine, âA Timeline for Martian Pioneers,â AAS 84-150, Christopher McKay, editor, The Case for
Mars II (San Diego, CA: Univelt, Inc., 1985), pp. 18-19.
36.
Michael Duke, Wendell Mendell, and Barney Roberts, âLunar Base: A Stepping Stone to Mars,â AAS 84-162,
Christopher McKay, editor, The Case for Mars II (San Diego, CA: Univelt, Inc., 1985), pp. 207-20.
37.
Humboldt Mandell, âSpace StationâThe First Step,â AAS 84-160, Christopher McKay, editor, The Case for
Mars II (San Diego, CA: Univelt, Inc.,1985), pp. 157-70.
38.
Welch and Stoker, The Case for Mars: Concept Development, p. 53.
39.
For examples, see Robert Farquhar, âLunar Communications with Libration-Point Satellites,â Journal of
Spacecraft and Rockets (October 1967): 1383, and Robert Farquhar, âA Halo-Orbit Lunar Station,â
Astronautics & Aeronautics (June 1972): 59-63. In 1971, Farquhar became involved in Harrison Schmittâs
effort to target Apollo 17 to the lunar farside crater Tsiolkovskii. He studied the possibility of placing com-
munication relay satellites in Lagrange point halo orbits to permit continuous communication between the
Apollo 17 moonwalkers at Tsiolkovskii and Mission Control on Earth (âLunar Backside Landing for Apollo
17,â presentation materials, 2 September 1971).
40.
Robert Farquhar and David Dunham, âLibration-Point Staging Concepts for Earth-Mars Transportation,â
Manned Mars Missions: Working Group Papers, Vol. 1 (Huntsville, AL, and Los Alamos, NM: NASA M002,
NASA/LANL, June 1986), pp. 66-77.
41.
Paul Keaton, A Moon Base/Mars Base Transportation Depot (Los Alamos, NM: LA-10552-MS, UC-34B, Los
Alamos National Laboratory, September 1985).
42.
Ibid., p. 10.
Endnotes
118
Monographs in Aerospace History
Chapter 8
1.
[Carl Sagan, Louis Friedman, and Bruce Murray], The Mars Declaration, special supplement to The
Planetary Report (November/December 1987). Author names revealed in Louis Friedman interview, 15
August 1999.
2.
National Commission on Space (NCOS), Pioneering the Space Frontier: The Report of the National
Commission on Space (New York: Bantam Books, May 1986).
3.
Lyn Ragsdale, âPolitics Not Science: The U.S. Space Program in the Reagan and Bush Years,â Spaceflight
and the Myth of Presidential Leadership, Roger Launius and Howard McCurdy, editors (Urbana, IL:
University of Illinois Press, 1997), p. 151.
4.
Carole Shifrin, âNASA Nears Final Decisions on Station Configuration,â Aviation Week & Space Technology
(10 March 1986): 107-109; NASA, âNASA Facts: Space Stationâ (Kennedy Space Center Press Release No.
16-86, January 1986).
5.
âNASA Managers Divided on Station,â Aviation Week & Space Technology (28 July 1986): 24-25; Craig
Covault, âLaunch Capacity, EVA Concerns Force Space Station Re-Design,â Aviation Week & Space
Technology (21 July 1986): 20; NASA, Space Station Freedom Media Handbook (Washington, DC: NASA,
April 1989), p. 7; Mark Hess, âNASA Proceeding Toward Space Station Developmentâ (Johnson Space
Center Press Release 87-50, 3 April 1987), p. 2.
6.
Paul Mann, âCommission Sets Goals for Moon, Mars Settlement in 21st Century,â Aviation Week & Space
Technology (24 March 1986): 18-21.
7.
Thomas Paine, âOverview: Report of the National Commission on Space,â Duke Reiber, editor, The NASA
Mars Conference (San Diego: Univelt, Inc., 1988), p. 533.
8.
NCOS, Pioneering, p. 191.
9.
âSpaced Out,â Aviation Week & Space Technology (15 September 1986): 11.
10.
Thomas Paine, âWho Will Lead the Worldâs Next Age of Discovery?â Aviation Week & Space Technology (21
September 1987): 43.
11.
Craig Covault, âRide Panel Calls for Aggressive Action to Assert U.S. Leadership in Space,â Aviation Week
& Space Technology (24 August 1987): 26.
12.
NASA, âStatement by Dr. Sally K. Ride, Associate Administrator for Exploration (Acting) before the
Subcommittee on Space Science and Applications, Committee on Science, Space, and Technology, House of
Representativesâ (22 July 1987), p. 1.
13.
Sally Ride, Leadership and Americaâs Future in Space (Washington, DC: NASA, August 1987), p. 5.
14.
Ride, Leadership, p. 21.
15.
NASA, âStatement by Dr. Sally K. Ride,â p. 2.
Endnotes
119
Humans to Mars: Fifty Years of Mission Planning, 1950â2000
16.
Ride, Leadership, p. 53.
17.
Ibid., p. 6.
18.
Craig Covault, âRide Panel Calls for Aggressive Action,â p. 26; NASA, Astronautics and Aeronautics 1986-
1990 (Washington, DC: NASA SP-4027), p. 126.
19.
Ride, Leadership, p. 55.
20.
Craig Covault, âRide Panel Will Urge Lunar Base, Earth Science as New Space Goals,â Aviation Week &
Space Technology (13 July 1987): 17; see also Michael Collins, Mission to Mars (New York: Grove Weidenfeld,
1990), pp. xii, 197.
21.
Ride, Leadership, p. 55.
22.
Ibid., p. 22.
23.
Ibid., p. 43.
24.
NASA, âStatement by Dr. Sally K. Ride,â p. 4.
25.
Ride, Leadership, p. 40.
26.
âNASA Forms Office to Study Manned Lunar Base, Mars Missions,â Aviation Week & Space Technology (8
June 1987): 22.
27.
Ride, Leadership, p. 53.
28.
Ibid., p. 47.
29.
Science Applications International Corporation, Piloted Sprint Missions to Mars (Schaumberg, IL: Report
No. SAIC-87/1908, Study No. 1-120-449-M26, November 1987).
30.
Ibid., p. 2.
31.
Ibid., p. 13; University of Texas and Texas A&M University Design Team, âTo MarsâA Manned Mars
Mission Study,â Summer Project Report (NASA Universities Advanced Space Design Program, Advanced
Programs Office, Johnson Space Center, August 1985).
32.
Ibid., p. 17.
33.
NASA, Astronautics and Aeronautics 1986-1990, p. 115.
34.
Office of Exploration, Exploration Studies Technical Report, FY 1988 Status, Volume 1: Technical Summary
(Washington, DC: NASA TM-4075, December 1988); Office of Exploration, âFY88 Exploration Studies
Technical Presentation to the Administrator,â presentation materials (25 July 1988).
35.
Martin Marietta, Manned Mars System Study (MMSS) Executive Summary (Denver, CO: Martin Marietta,
July 1990).
Endnotes
120
Monographs in Aerospace History
36.
Clark interview, 27 August 1999.
37.
David S. F. Portree, Thirty Years Together: A Chronology of U.S.-Soviet Space Cooperation (Houston: NASA
CR-185707, February 1993), pp. 26-27.
38.
Harvey Meyerson, âSpark Matsunaga 1916-1990,â The Planetary Report (July/August 1990): 26.
39.
Philip Klass, âCommission Considers Joint Mars Exploration, Lunar Base Options,â Aviation Week & Space
Technology (29 July 1985): 47.
40.
Carl Sagan, âTo Mars,â Aviation Week & Space Technology (8 December 1986): 10.
41.
The Mars Declaration.
42.
Richard OâLone, âScientist Sees Space Station Useful Only If Linked to Manned Mars Mission,â Aviation
Week & Space Technology (25 January 1988): 55, 57.
43.
Portree, Thirty Years Together, p. 30.
44.
V. Glushko, Y. Semyonov, and L. Gorshkov, âThe Way to Mars,â The Planetary Report (November-December
1988): 4-8. Translation of Pravda article dated 24 May 1988.
Chapter 9
1.
NASA, Report of the 90-Day Study on Human Exploration of the Moon and Mars (Washington, DC: NASA,
November 1989), pp. 9-12 - 9-13.
2.
Aaron Cohen interview by David S. F. Portree, 27 August 1999.
3.
Craig Covault, âSpace Policy Outlines Program to Regain U.S. Leadership,â Aviation Week & Space
Technology (22 February 1988): 20.
4.
âNASA Funds $100-Million Pathfinder Program for Mars, Lunar Technology,â Aviation Week & Space
Technology (18 January 1988): 17.
5.
Dwayne Day, âDoomed to Fail,â Spaceflight (March 1995): 80.
6.
Office of the White House Press Secretary, âRemarks of the President at the 20th Anniversary of Apollo
Moon Landingâ (Washington, DC: White House, 20 July 1989).
7.
âSpace Wraith,â Aviation Week & Space Technology (24 July 1989): 21.
8.
Mark Craig interview by David S. F. Portree, 13 September 1999.
9.
Richard Truly and Franklin Martin, âBriefing to NASA Employees,â presentation materials (26 July 1989).
10.
Ivan Bekey interview by David S. F. Portree, 7 September 1999.
Endnotes
121
Humans to Mars: Fifty Years of Mission Planning, 1950â2000
11.
âNASA Accelerates Lunar Base Planning as Station Changes Draw European Fire,â Aviation Week & Space
Technology (18 September 1999): 26-27.
12.
Humboldt Mandell interview by David S. F. Portree, 13 September 1999.
13.
Cohen interview, 27 August 1999.
14.
Ibid.
15.
NASA, âCost Summary,â unpublished chapter in Report of the 90-Day Study on Human Exploration of the
Moon and Mars, p. 2.
16.
Ibid., p. 3.
17.
Ibid.
18.
Ibid., p. 4.
19.
Ivan Bekey, âA Smaller Scale Manned Mars Evolutionary Program,â IAF-89-494 (paper presented at the
40th Congress of the International Astronautical Federation, Malaga, Spain, 7-12 October 1989), p. 6.
20.
Bekey interview, 7 September 1999.
21.
Rod Hyde, Yuki Ishikawa, and Lowell Wood, âAn American-Traditional Space Exploration Program: Quick,
Inexpensive, Daring, and Tenacious, Briefing to the National Space Councilâ (Livermore, CA: LLNL Doc. No.
Phys. Brief 89-403, September 1989).
22.
Day, âDoomed to Fail,â p. 81.
23.
âSpace Policy,â Aviation Week & Space Technology (30 October 1989): 15; John Connolly, personal communi-
cation.
24.
Craig interview, 13 September 1999.
25.
Roderick Hyde, Muriel Ishikawa, and Lowell Wood, âMars in this Century: The Olympia Project,â UCRL-
98567, DE90 008356, Lawrence Livermore National Laboratory (paper presented at the U.S. Space
Foundation 4th National Space Symposium, Colorado Springs, Colorado, 12-15 April 1988).
26.
R. A. Hyde, M. Y. Ishikawa, and L. L. Wood, âToward a Permanent Lunar Settlement in the Coming Decade:
The Columbus Projectâ (Lawrence Livermore National Laboratory: UCRL-93621, DE86 006709, 19
November 1985).
27.
Hyde, et al., âAn American-Traditional Space Exploration Program,â p. 38.
28.
Ibid., p. 3-4.
29.
âNotice to NASA,â Aviation Week & Space Technology (15 January 1990): 15.
30.
Committee on the Human Exploration of Space, Human Exploration of Space: A Review of NASAâs 90-Day
Study and Alternatives (Washington, DC: National Academy Press, 1990), p. x.
Endnotes
122
Monographs in Aerospace History
31.
Ibid., p. 28.
32.
Ibid., p. 3.
33.
Ibid., pp. xii-xiii.
34.
Ibid., p. x.
35.
âBush Calls for Two Proposals for Missions to Moon, Mars,â Aviation Week & Space Technology (12 March
1990): 18.
36.
Breck Henderson, âLivermore Plan for Exploring Moon, Mars Draws Space Council Attention,â Aviation
Week & Space Technology (22 January 1990): 84.
37.
Douglas Isbell, âCongress Says OK to Moon, Mars Work,â Space News (28 May-3 June 1990): 3, 20.
38.
Douglas Isbell, âEx-Astronaut Stafford to Head Moon-Mars Outreach Team,â Space News (4-10 June 1990): 4.
39.
Mandell interview, 13 September 1999.
40.
Andrew Lawler, âBush: To Mars by 2019,â Space News (14-20 May 1990): 1.
41.
Patricia Guilmartin, âHouse Kills Funding for Moon/Mars Effort,â Aviation Week & Space Technology (2 July
1990): 28.
42.
âDarman Backs NASA,â Aviation Week & Space Technology (21 May 1990): 17.
43.
Douglas Isbell and Andrew Lawler, âSenators Assail Bush Plan,â Space News (7-13 May 1990): 1.
44.
âBush Sets 2019 Manned Mars Objective,â Aviation Week & Space Technology (21 May 1990): 19.
45.
Andrew Lawler, âBush Moon-Mars Plan Handed First Defeat,â Space News (18-24 June 1990): 3.
46.
NASA, Astronautics and Aeronautics 1986-1990 (Washington, DC: NASA SP-4027), pp. 272-73.
47.
Craig Covault, âWhite House Endorses Plan for Shuttle, Station Scale-Back,â Aviation Week & Space
Technology (17 December 1990): 20; NASA, Astronautics and Aeronautics 1986-1990, p. 287.
48.
âU.S. Astronaut to Visit Soviet Station, Cosmonaut to Fly on Shuttle,â Aviation Week & Space Technology (22
October 1990): 24.
49.
âSenior Soviet Space Officials Outline Plan for Joint Mars Mission,â Aviation Week & Space Technology (19
November 1990): 67; Arnold Aldrich to Distribution, âBackground Material on Cooperation with NPO
Energiaâ (29 June 1992).
50.
Leonard David, âFaster, Cheaper Mars Exploration Proposed,â Space News (11-17 June 1990): 4.
51.
Yuri Semyonov and Leonid Gorshkov, âDestination Mars,â Science in the USSR (July-August 1990): 15-18.
Endnotes
123
Humans to Mars: Fifty Years of Mission Planning, 1950â2000
52.
Ibid., p. 17.
53.
Scientific Industrial Corporation âEnergia,â Mars Manned Mission: Scientific/Technical Report (Moscow,
Russia: USSR Ministry of General Machinery, 1991), p. 1.
54.
Ibid., p. 15.
55.
SEI Synthesis Group, America at the Threshold: Americaâs Space Exploration Initiative (Washington, DC:
Government Printing Office, May 1991).
56.
âReaching Out,â Aviation Week & Space Technology (4 June 1990): 15; Craig Covault, âExploration Initiative
Work Quickens as Some Concepts Avoid Station,â Aviation Week & Space Technology (17 September 1990):
36.
57.
Astronautics and Aeronautics 1986-1990, p. 255.
58.
Covault, âExploration Initiative Work Quickens,â p. 36.
59.
America at the Threshold, p. 52.
60.
Ibid., p. 8.
61.
Kent Joosten, personal communication.
Chapter 10
1.
Kent Joosten, Ryan Schaefer, and Stephen Hoffman, âRecent Evolution of the Mars Reference Mission,â
AAS-97-617 (paper presented at the AAS/AIAA Astrodynamic Specialist Conference, Sun Valley, Idaho, 4-7
August 1997), p. 1.
2.
Robert Zubrin with Richard Wagner, The Case for Mars (New York: Free Press, 1996), pp. 51-52; Benton
Clark interview by David S. F. Portree, 30 September 1999.
3.
Zubrin and Wagner, The Case for Mars, p. 65.
4.
Leonard David, âFaster, Cheaper Mars Exploration,â p. 37.
5.
Robert Zubrin and David Baker, âHumans to Mars in 1999,â Aerospace America (August 1990): 30-32, 41.
For other examples, see Zubrin and Benjamin Adelman, âThe Direct Route to Mars,â Final Frontier
(July/August 1992): 10-15, 53, 55; Zubrin and Christopher McKay, âPioneering Mars,â Ad Astra
(September/October 1992): 34-41; Zubrin, âThe Significance of the Martian Frontier,â Ad Astra
(September/October 1994): 30-37; Zubrin, âMars: Americaâs New Frontier,â Final Frontier (May/June 1995):
42-46; Zubrin, âThe Economic Viability of Mars Colonization,â Journal of the British Interplanetary Society
(October 1995): 407-414; Zubrin, âThe Promise of Mars,â Ad Astra (May/June 1996): 32-38; Zubrin, âMars on
a Shoestring,â Technology Review (November/December 1996): 20-31; Zubrin, âSending Humans to Mars,â
Scientific American Presents (Spring 1999): 46-51; Zubrin, âThe Mars Direct Plan,â Scientific American
(March 2000): 52-55.
Endnotes
124
Monographs in Aerospace History
6.
Zubrin and Baker, p. 30.
7.
Ibid, p. 31.
8.
Martin Marietta, Manned Mars System Study (Mars Transportation and Facility Infrastructure Study),
Volume II, Final Report (Denver, CO: Martin Marietta, July 1990), pp. 4-11 - 4-16.
9.
Zubrin and Baker, p. 41.
10.
Michael Duke and Nancy Anne Budden, editors, Mars Exploration Study Workshop II (Houston: NASA CP-
3243, November 1993), p. iii.
11.
Exploration Programs Office, âEXPO Mars Program Study, Presentation to the Associate Administrator for
Exploration,â presentation materials (9 October 1992).
12.
Zubrin with Wagner, The Case for Mars, pp. 66-67.
13.
David Weaver and Michael Duke, âMars Exploration Strategies: A Reference Program and Comparison of
Alternative Architectures,â AIAA 93-4212 (paper presented at the AIAA Space Program and Technologies
Conference, Huntsville, Alabama, 21-23 September 1993).
14.
Duke and Budden, Mars Exploration Study Workshop II.
15.
Robert Zubrin and David Weaver, âPractical Methods for Near-Term Piloted Mars Missions,â AIAA 93-2089
(paper presented at the AIAA/SAE/ASME/ASEE 29th Joint Propulsion Conference, Monterey, California,
28-30 June 1993), p. 3. In a 30 September 1999 interview with the author, Benton Clark compared the Mars
Direct ERV volume per crewmember to âa telephone booth.â See also David S. F. Portree, âThe New Martian
Chronicles,â Astronomy (July 1997): 32-37.
16.
Kent Joosten, personal communication.
17.
Donald Savage and James Gately, âMars Observer Investigation Report Releasedâ (Washington, DC: NASA
Headquarters Press Release 94-1, 5 January 1994).
18.
Tim Furniss, âRed Light?â Flight International (6-12 October 1993): 28-29.
19.
Kent Joosten, personal communication.
20.
Donald Savage, James Hartsfield, and David Salisbury, âMeteorite Yields Evidence of Primitive Life on
Early Marsâ (NASA Headquarters Press Release 96-160, 7 August 1996).
21.
Everett Gibson, David McKay, Kathie Thomas-Keprta, Christopher Romanek, âThe Case for Relic Life on
Mars,â Scientific American (December 1997): 58-65.
22.
Kent Joosten, personal communication.
23.
Associate Administrators for HEDS Enterprise and Associate Administrator for Space Science Enterprise
to Director, Jet Propulsion Laboratory, and Director, Lyndon B. Johnson Space Center, âIntegration of Mars
Exploration Study and Planning,â 7 November 1996, p. 1.
Endnotes
125
Humans to Mars: Fifty Years of Mission Planning, 1950â2000
24.
Ibid., pp. 1-2.
25.
Ibid., p. 2.
26.
Douglas Isbell and Michael Braukus, âSpace Science and Human Space Flight Enterprises Agree to Joint
Robotic Mars Lander Missionâ (NASA Headquarters Press Release 97-51, 25 March 1997).
27.
Stephen Hoffman and David Kaplan, editors, Human Exploration of Mars: The Reference Mission of the
NASA Mars Exploration Study Team (Houston: NASA SP-6017, July 1997).
28.
Ibid., pp. 1-36 - 1-37, 1-41.
29.
Ibid., p. v.
30.
Kent Joosten, et al.
31.
Michael Duke, editor, Mars Surface Mission Workshop, LPI Contribution 934 (Houston: Lunar and
Planetary Institute, 1998).
32.
Mars Exploration Study Team, âMars Exploration Study Program: Report of the Architecture Teamâ (pres-
entation materials, 6 April 1999), p. 6. The three-pronged approach to Mars exploration apparently dates
from a March 1995 NASA Solar System Exploration Subcommittee meeting (Don Bogard, personal com-
munication); it became widely applied to NASA Mars planning only after the McKay teamâs announcement
in August 1996.
33.
Duke, Mars Surface Mission Workshop, p. 8.
34.
Bret Drake, editor, Reference Mission Version 3.0, Addendum to the Human Exploration of Mars: The
Reference Mission of the NASA Mars Exploration Study Team, EX13-98-036 (Houston: NASA Johnson Space
Center Exploration Office, June 1998), pp. 33-37.
35.
David S. F. Portree, âWalk This Way,â Air & Space Smithsonian (October/November 1998): 45-46.
36.
Nancy Anne Budden and Michael B. Duke, editors, HEDS-UP Mars Exploration Forum, LPI Contribution
955 (Houston: Lunar and Planetary Institute, 1998).
37.
Michael Duke, editor, Second Annual HEDS-UP Forum, LPI Contribution 979 (Houston: Lunar and
Planetary Institute, 1999).
127
Humans to Mars: Fifty Years of Mission Planning, 1950â2000
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141
Humans to Mars: Fifty Years of Mission Planning, 1950â2000
About the Author
Aaron, John, 73
Abbey, George, 94, 95
Acta Astronautica, 55
aerobraking, 16, 20, 21, 57, 59, 62, 63, 71, 72, 73, 79, 80,
89, 90, 92, 95, 96
Aerojet-General Corporation, 34, 35
Aeronutronic, 12, 13, 15, 16, 23; MEM description, 16
18; see also EMPIRE
Aerospace Industries Association, 82, 85
Aerospace Technology, 39
Agnew, Spiro, 42, 44, 46, 47
Air Forceâsee United States Air Force
alcohol, 1
Aldrin, Edwin âBuzz,â 43; and cyclers, 63
ALH 84001, 94
American Astronautical Society (AAS): Symposium on
the Manned Exploration of Mars, 15, 35, 58; Fifth
Goddard Memorial Symposium, 30
American Astronomical Society, 24
American Institute of Astronautics and Aeronautics
(AIAA), 74, 85; Aerospace America, 89; Steps to
Mars conference, 73-74; 3rd Manned Spaceflight
Conference, 16
Ames Research Center (ARC)âsee under NASA
Anders, William, 41
Anderson, Clinton, 5, 34, 35, 46, 52
Antarctica, 2, 94
Antoniadi crater, 17
Apollo Applications Program (AAP), 24, 26, 29, 30, 31,
32, 42, 46
Apollo mission modes: Direct-Ascent, 7, 8; Earth-Orbit
Rendezvous (EOR), 7; Lunar Orbit Rendezvous
(LOR), 8, 9; LOR impact on Mars plans, 8-9
Apollo Program, 2, 7, 8, 11, 12, 15, 18, 21, 24-27, 29, 30,
33, 37, 38, 40, 42, 45-49, 51, 53, 55, 58, 70, 73, 74,
77, 78, 82, 86, 94, 95, 98; poorly timed as lead-in
to piloted Mars flights, 11; deviation from von
Braun plan, 12
Apollo missions: Apollo 1, 30; Apollo 4, 33; Apollo 7, 40;
Apollo 8, 41, 49; Apollo 10, 86; Apollo 11, 43, 46,
47, 48, 57, 63, 70, 77; Apollo 13, 41; Apollo 15, 51;
Apollo 17, 60; Apollo 20, 48
Apollo-Soyuz Test Project, 57, 73
Apollo technology:
Command and Service Module
(CSM), 13, 21, 22, 26, 28, 30, 33, 36, 37, 39, 40, 41,
43, 57; Command Module (CM), 13, 14, 22, 25, 26,
33, 36, 37, 61, 81, 85, 86; Lunar Module (LM), 18,
21, 41, 43, 63; Lunar Roving Vehicle, 51; Service
Module (SM), 13, 22; as source of Mars mission
technology, 9, 21, 26, 58; see also Saturn rockets,
Saturn rocket modifications
Ares Vallis, 95
argon, 17, 58
Armstrong, Neil, 2, 43, 45, 67
Armyâsee United States Army
artificial gravity, 2, 8, 13, 14, 20, 21, 51, 59, 80, 81, 89, 90
Ash, Robert, 55, 56, 89, 90
Asteroid Belt, 13, 27, 29
Atlas missile, 13, 20
Atomic Energy Commission (AEC), 5, 12, 26, 33, 34, 35,
42, 52; Los Alamos National Laboratory (LANL),
34, 61, 62, 84, 86
Aviation Week & Space Technology, 30, 31, 41, 42, 43,
46, 48, 68, 69, 70, 74, 78, 86
Baikonur Cosmodrome, 74
Baker, David, 89-91
ballute, 38
Bay of Pigs, 6
Beggs, James, 73
Bekey, Ivan, 80; and Office of Exploration task force,
80-81
Bellcomm, 25, 29
Berlin Airlift, 1
Bialla, Paul, 82
Bible, Alan, 52
biological contamination, 17, 31, 45, 51, 95
Boeing Company, 44, 50, 73; Mars âcruiserâ description,
36-39
Bonestell, Chesley, 2
Borman, Frank, 41
Boulder Center for Science and Policy, 63
British Interplanetary Society, 35
Bush, George, 67, 75, 77-85, 87; launches Space
Exploration Initiative, 77-78; sets timetable for
Americans on Mars, 83
Cannon, Howard, 40
Cape Kennedy, 53
Capitol Hill, 23, 29, 30, 49, 52; see also Congress
carbon dioxide, 17, 20, 23, 55, 56, 67, 90, 93
carbon monoxide, 55, 64, 90
Carter, Jimmy, 60
Case for Mars, The, 57, 58, 63, 67, 84, 87, 89; âMars
Underground,â 57, 58
Cecropia region, 17
Centaur upper stage, 13
Central Intelligence Agencyâsee under United States
Government
143
Humans to Mars: Fifty Years of Mission Planning, 1950â2000
Index
cesium, 7, 8
Chaffee, Roger, 30
chemical propulsion, 5, 7, 12, 13, 16, 34, 50, 58, 84, 97, 98
Chernobyl, 84
Chryse Planitia, 54
Clark, Benton, 53, 56, 58, 63, 84, 89; âThe Viking
Resultsâthe Case for Man on Mars,â 56, 58
Clinton, William, 85
Cohen, Aaron, 77, 78, 79, 80, 81
Cold War, 6, 73, 74, 77, 81
Collierâs, 2, 3, 7, 42, 98
Collins, Michael, 43; and NASA Advisory Council Task
Force, 70
Congress, 5, 6, 7, 23, 24, 30, 31, 34, 35, 39, 40, 44, 52, 67,
77, 78, 82, 83; funds first NASA Mars study, 5;
response to NASA Space Task Group presenta
tion, 46, 47; response to Space Exploration
Initiative,
78,
82-84;
see also
House of
Representatives, Senate
conjunction-class mission, 2, 19, 37, 55, 56, 80, 89, 91
Connolly, John, vii
Cooke, Doug, 94
coriolis effect, 8
Cornell University, 74
Craig, Mark, 78
Crippen, Robert, 57
Crocco, Gaetano, 11, 12
Crocco-type flyby, 11, 15, 63
cyclers, 63, 64, 68
Darman, Richard, 77, 83
Deimos, 13, 53, 58, 81
Democrat, 5, 31, 32, 34, 39, 40, 41, 47, 52, 83
Department of Commerceâsee under United States
Government
Department of Defenseâsee under United States
Government
Department of Energy, 81, 82, 85; Lawrence Livermore
National Laboratory (LLNL), 81, 82
Department of Stateâsee under United States
Government
Department of Transportationâsee under United
States Government
Design Reference Mission (DRM), 89, 91, 94, 95, 96, 97;
cargo lander, 92, 93, 96, 98; Earth-Return Vehicle,
91, 92, 93, 96, 98; Habitat, 92, 93, 95, 96, 98; High-
Energy Elliptical Parking Orbit (HEEPO), 98;
Human Exploration of Mars:
The Reference
Mission of the NASA Mars Exploration Study
Team, 95; Mars Ascent Vehicle (MAV), 91, 92, 93;
Mars Exploration Study Team, 91, 93; relation
ship to Mars Direct, 91-92; âscrubbedâ DRM, 95,
98; Solar-Electric Transport Vehicle (SETV), 97,
98; surface payload, 96-97; âthree-pronged
approachâ to Mars science, 97
Disney, Walt, 7
Dixon, Franklin, 16, 17, 18; âManned Expeditions to
Mars and Venus,â 30
Douglas Aircraft Company, 18
Dowler, William, 55, 56, 90
Dubridge, Lee, 42, 44
Dukakis, Michael, 83
Duke, Michael, 63, 96, 97, 98
Dunham, David, 64
Eagle Engineering, 68, 73
Economist, The, 49
Ehricke, Krafft, 13-15
electric propulsion, 5, 7, 8, 58, 68, 84, 85, 97
Eisenhower, Dwight, 5-7
EMPIRE (Early Manned Planetary Interplanetary
Roundtrip Expeditions), 9, 11, 12, 14, 15, 18, 19,
21, 29, 35, 36, 73
encounter missionâsee under piloted Mars flyby
Energia rocket, 74, 75, 84, 85; and Buran shuttle, 75
Explorer 1, 4, 6, 7, 47
Explorer 3, 6
Ezell, Edward, 21
Faget, Maxime, 12, 15, 21, 23, 30, 50, 85
Farquhar, Robert, 64
Finger, Harold, 35
First Lunar Outpost (FLO), 91
Fisher, William, 83
Flanigan, Peter, 49
Fletcher, James, 52, 69, 70
flybyâsee piloted Mars flyby
Flyby-Landing Excursion Mode (FLEM), 29
Flyby-Rendezvous mode, 15, 16, 59
Ford, Gerald, 55, 82
Freeman, Fred, 2
Friedman, Louis, 55, 58, 59
Frosch, Robert, 60
Fulbright, J. W., 47
Future Projects Officeâsee under Marshall Space
Flight Center
Gagarin, Yuri, 6
Gemini, 12, 29, 30, 31, 33
144
Monographs in Aerospace History
Index
General Dynamics, 12, 13, 14, 15, 18, 82; see also
EMPIRE
General Electric, 40
Genesis, 41
Glushko, Vladimir, 74
Gorbachev, Mikhail, 73, 74, 84, 85
Gore, Albert, 83
Gorshkov, Leonid, 74, 84
Gramm-Rudman deficit reduction legislation, 83
Gray, Edward, 25; âManned Expeditions to Mars and
Venus,â 30
Great Exploration, The, 81-82
Green, Bill, 83
Griffin, Michael, 91
Grissom, Gus, 30
Gusev crater, 54
Haber, Heinz, 2
Habitability of Mars, The, 58
halo orbit, 64
Hammock, David, 15, 16
Hatfield, Mark, 46
heavy-lift rocket, 60, 61, 63, 68, 71, 72, 80, 84, 85, 86, 89,
91, 92, 96, 97; Advanced Launch System, 79; HL
Delta rocket, 81; Nova rocket, 7, 9, 12, 13; Titan
VI rocket, 81; see also Energia rocket, Saturn
rocket, Saturn rocket modifications, Shuttle-
derived rocket
Hellas basin, 43
Hellespontus region, 43
Heppenheimer, T. A., 11
Hitler, Adolf, 13
Holland, Spessard, 31
Hollister, Walter, 63
Hoffman, Stephen, 89
Hotz, Robert, 31, 46
Houbolt, John, 8
House, William, 35
House of Representatives,
31,
32,
83,
84;
Appropriations Committee, 83; Science and
Astronautics Committee, 47; Space Committee,
26, 31, 39, 68; Subcommittee on Housing and
Urban Development and Independent Agencies,
83;
Subcommittee on Space Science and
Applications, 32, 69, 70
Hubble Space Telescope, 83
Human Exploration and Development of Space-
University Partners (HEDS-UP), 98, 99.
Humphrey, Hubert, 40
Huntress, Wesley, 94, 95
hydrogen, 5, 13, 22, 26, 33, 34, 35, 36, 43, 44, 51, 55, 57,
61, 72, 81, 83, 89, 90, 92, 93
hydrogen peroxide, 56
inflatable structures, 1, 2, 3, 81, 97
In-Situ Resource Utilization (ISRU), 55, 56, 58, 62-64,
79, 80, 86, 89, 91, 92, 95, 99
integrated program, 26
Integrated Program Plan (IPP), 42-44, 48, 78
Interplanetary Shuttle Vehicle (ISV), 64
International Astronautical Federation Congress, 11, 80
International Sun-Earth Explorer-3, 64
International Space Year, 69
Internet, 98, 99
Jackson, Bruce, 15, 16
Jenkins, Morris, 50-51
Jet Propulsion Laboratory (JPL), 61, 63, 74, 77, 78, 79,
85, 87, 91, 93, 94, 95, 97; and Voyager, 25; and
ISRU, 55
Johnson, Lyndon, 21, 24, 29-32, 34, 35, 39-42; cancels
Reactor-In-Flight-Test (RIFT), 35; requests
NASAâs post-Apollo plans, 24
Johnson Space Center (JSC), 15, 60, 61, 77, 79, 94;
Exploration Directorate, 87, 93; Exploration
Office, 94, 95; Lunar-Mars Exploration Program
Office, 78; Office of the Curator, 94; Planetary
Projects Office, 93, 94; see also Manned
Spacecraft Center
Johnson, U. Alexis, 42
Joosten, Kent, vii, 89
Jupiter (planet), 7, 53
Jupiter-C rocket, 7
Kaplan, Joseph, 2
Karth, Joseph, 32
Keaton, Paul, 61, 64
Kennedy, John F., 7, 8, 12, 24, 29, 33-35, 41, 48, 49, 75,
77; decision to go to the Moon, 5-6, 15; and
nuclear rockets, 34-35
Kennedy, Robert, 39
Kennedy Space Center (KSC), 25, 29, 30, 33, 37, 49, 57,
80, 89; Pad 39C, 28, 31, 37
Kennedyesque proclamation, 78
kerosene, 33
Keyworth, George, 69
King, Martin Luther, Jr., 39.
Kirkpatrick, Jeane, 67
Klep, Rolf, 2
Koelle, Heinz, 11, 21
145
Index
Humans to Mars: Fifty Years of Mission Planning, 1950â2000
Kraft, Christopher, 85
Lagrange, Joseph, 64
Lagrange point station, 63, 68; as stepping stone to
Mars, 64
Laird, Melvin, 42
Langley Research Center, 8, 15, 20, 32, 36, 42; supports
ISRU research, 56
Launius, Roger, 41
Leadership and Americaâs Future in Space (Ride
Report), 69-73, 81, 89
Lewis Research Center, 5, 6, 8, 9, 15, 19, 34, 85, 97, 98;
and first NASA Mars study, 5-6, 37; and Design
Reference Mission, 97-98; see also NASAâGlenn
Research Center at Lewis Field
Ley, Willy, 2, 3
Life Systems, 73
lifting body, 13, 15, 16, 17, 20, 23
lithium, 85
Lockheed Missiles and Space Company, 12, 13, 14, 29,
35; see also EMPIRE
Logsdon, John, vii, 48
Los Alamos National Laboratory (LANL)âsee under
Atomic Energy Commission (AEC)
Los Angeles Herald-Examiner, 43
Lovell, James, 41
Low, George, 41, 49, 52, 74
Lowell, Percival, 23, 53
Lunar and Planetary Institute, 97
Lunar Bases and Space Activities of the 21st Century, 61
Lunar Orbiter, 53
Lunokhod 2, 95
Manarov, Musa, 74
Mandell, Humboldt, 63, 79
Manned Mars Mission (MMM): study, 51, 61, 84; work
shop, 61, 64
Manned Spacecraft Center (MSC), 15, 16, 19, 25, 31, 32,
37, 41, 49, 50, 59, 60, 80; and Planetary Missions
Requirements Group, 49-51; see also Johnson
Space Center
Margaritifer Sinus region, 3
Mariner, 26, 53; Mariner 2, 12, 23; Mariner 4, 22, 23, 24,
25, 30, 37, 44; Mariner 6, 43-44, 53; Mariner 7, 43-
44, 46, 53; Mariner 9, 53, 54, 55, 95
Mars: affect of environment on unprotected human, 54;
atmosphere, 16, 17, 20, 21, 23, 24, 25, 37, 38, 54-
56, 67, 86, 90; canals, 2-4, 23; channels, 53, 54, 95;
dust, 53, 54, 97, 99; opposition, 3, 4, 18, 19, 53, 75;
permafrost, 53, 54; poles, 1, 17, 18, 43, 67; popular
image, 23, 53, 54, 55; water, 17, 23, 53, 54, 55, 56,
81, 94, 98; as an abode of life, 2, 3, 15, 17, 23, 26,
29, 45, 51, 53, 54, 71, 89, 94, 97, 98; as base/set
tlement site, 2, 19, 21, 45, 55, 56, 60, 62, 63, 70, 71,
79, 80, 81, 89, 90, 91, 92, 93, 97; as revealed by
Mariner 4, 23; as revealed by Mariner 9, 53, 55;
as revealed by Viking, 54-55
Mars and Beyond, 7
Mars Declaration, Theâsee under Planetary Society,
The
Mars Direct, 85, 89-92; small Earth-Return Vehicle, 91;
see also Design Reference Mission
Mars Exploration Study Teamâsee under Design
Reference Mission
Mars Global Surveyorâsee under Mars Surveyor
Program
Mars Observer, 93, 94, 96
Mars Orbit Rendezvous (MOR), 9, 14, 15, 16, 29, 37, 63,
93; see also piloted Mars landers
Mars Pathfinder, 89, 95; renamed Sagan Memorial
Station, 95
Mars Surface Sample Return (MSSR) landerâsee
under piloted Mars flyby
Mars Surveyor Program, 94, 95, 96; Mars Global
Surveyor, 96, 98
Mars Transportation and Facility Infrastructure Study
âsee under Martin Marietta Corporation
âMars Undergroundââsee under Case for Mars, The
Marshall Space Flight Center, 7, 9, 11, 12, 15, 18, 20, 21,
24, 25, 35, 44, 49, 55, 61, 73, 89; Future Projects
Office, 11, 12, 18, 20, 21, 24, 44; Symposium on
Manned Planetary Missions, 16, 21
Martian meteoriteâsee ALH 84001
Martin, Franklin, 77, 78
Martin Marietta Corporation, 15, 56, 73, 80, 85, 89, 90;
Mars Transportation and Facility Infrastructure
Study, 73, 80
Matsunaga, Spark, 73
Mayo, Robert, 42, 44, 46-48
McGill University, 94
McKay, Christopher, 57, 58, 63
McKay, David, 94
Mendell, Wendell, 63
Mercury (planet), 53
Mercury, 12, 15, 31, 33; Freedom 7, 6
Meteor Crater, 98
meteoroids, 8, 13, 14, 17, 19, 23, 62, 97
methane, 38, 39, 55, 56, 90, 91, 92, 93
Mie crater, 54
Miller, George, 47
146
Monographs in Aerospace History
Index
Moon, 1, 2, 5, 6, 7, 9, 11, 14, 22, 24, 28, 29, 33, 34, 41, 42,
43, 45, 47, 48, 49, 53, 54, 60, 61, 64, 70, 77, 78, 79,
80, 81, 82, 83, 84, 86, 94, 95, 96; base site, 12, 43,
47, 60, 61, 68, 70, 73, 77, 78, 79, 81, 86, 89, 91;
âimportant for the long-range exploration of
space,â 5, 8; source of oxygen propellant for Mars
flight, 68, 78; stepping stone to Mars, 15, 63, 70,
73, 77, 78, 86
Morgenthaler, George, 15
Mueller, George E., 25, 26, 40, 42, 43, 46, 48
Murray, Bruce, 74
nanobacteria, 94
National Academy of Sciences, 61, 68; Space Science
Board, 24; Space Research: Directions for the
Future, 24
National Advisory Committee on Aeronautics
(NACA)âsee under United States Government
NASA (National Aeronautics and Space Administration),
4, 5, 6, 7, 8, 9, 11, 12, 15, 17, 23, 30, 32, 33, 35, 37,
40, 44, 46, 47, 48, 49, 51, 52, 55, 57, 58, 59, 61, 68,
73, 77, 78, 79, 81, 82, 83, 84, 85, 86, 89, 93, 94, 95,
98; Advisory Council Task Force, 70; Ames
Research Center (ARC), 19, 49, 63; budget, 5, 23,
24, 25, 29, 30, 31, 32, 39, 40, 42, 46, 48, 49, 52, 59,
68, 70, 77, 78, 83, 84; Exploration Office, 87, 91, 93,
94; Glenn Research Center at Lewis Field, 5;
Goddard Space Flight Center, 64; Headquarters,
15, 25, 27, 82, 94; Human Exploration and
Development of Space (HEDS) Enterprise, 94, 95;
Manned Planetary Mission Technology
Conference, 15; Mars Conference, 68; Mission to
Planet Earth, 69, 84; Office of Exploration, 70, 71,
73, 80, 90, 91; Office of Manned Space Flight
(OMSF), 25, 27, 30, 40, 42; Planetary Missions
Requirements Group (PMRG); 48-51, 80; Science
and Technical Advisory Council, 42; Science and
Technology Advisory Committee, 25; Space Science
Enterprise, 94, 95; see also individual NASA
Centers, Design Reference Mission, Jet Propulsion
Laboratory (JPL), Planetary Joint Action Group
National Commission on Space (NCOS), 67, 68, 69, 70,
85, 89; Pioneering the Space Frontier, 67
National Press Club, 46
National Research Council (NRC), 77, 82; Committee
on Human Exploration of Space (Stever
Committee), 82
National Space Councilâsee under White House
National Space Society, 89
New York Times, 44
Newsweek, 74
Nicogossian, Arnauld, 94
Niehoff, John, 71, 72
nitric acid, 1
nitrogen, 17, 20, 23, 54
Nix Olympica, 43, 53âsee also Olympus Mons
Nixon, Richard M., 6, 34, 40, 41, 42, 47, 48, 49, 52, 74,
82; supports Space Shuttle, 52; Task Force on
Space, 41, 42, 46
North American Rockwell (NAR), 51, 44, 85; MEM
description, 37-39
NPO Energia, 84, 85
nuclear reactor, 8, 34, 84, 89, 90
nuclear propulsion, 3, 5, 6, 8, 12, 14, 16, 25, 26, 29, 32,
34, 35, 36, 40, 46, 48, 50, 52, 61, 84, 86, 89, 92, 96,
97; Kiwi, 34, 35; NERVA (Nuclear Engine for
Rocket Vehicle Application), 33, 34, 35, 36, 40, 41,
43, 44, 45, 48, 52, 96; NRX-A6 ground test, 35;
Reactor-In-Flight-Test (RIFT), 35; ROVER, 34
Nuclear Rocket Development Station (NRDS), 34, 40, 52
Nuclear Shuttle, 43-45
Office of Manned Space Flight (OMSF)âsee under
NASA
Old Dominion University, 55, 56
Olympus Mons, 53; see also Nix Olympica
opposition-class mission, 19, 36, 37, 80
Orbital Transfer Vehicle (OTV), 57, 59, 60, 61, 62, 68,
72, 73
Outreach Programâsee under Space Exploration
Initiative (SEI)
oxygen, 8, 17, 22, 33, 34, 38, 39, 51, 55, 56, 57, 61, 64, 68,
72, 73, 78, 79, 81, 89, 90, 91, 92, 93
Paine, Thomas, 33, 40-44, 46-49, 52, 63, 67-69
PeenemĂŒnde, 1, 13
Pentagon, 79; see also United States Governmentâ
Department of Defense
periodic-orbit stations, 63; see also cyclers
PH-D Proposal, 58
Philadelphia Inquirer, 43
Phillips, Samuel, 82
Phobos (Martian moon), 13, 53, 58, 73, 74, 80, 81
Phobos spacecraft, 74-75
piloted Mars flyby, 11-13, 15, 21, 22, 24, 25, 26, 27, 30,
32, 58, 61, 62, 74; Apollo-based Earth-return cap-
sule, 13, 14, 21, 22, 25, 26; automated probe cargo,
12, 13, 21, 22, 25, 26, 27, 28, 31, 32; âcoolâ versus
âhotâ trajectory, 13; deviation from von Braun
plan, 12; encounter mission, 30, 31; Experiment
147
Index
Humans to Mars: Fifty Years of Mission Planning, 1950â2000
Module, 25, 27, 28, 29, 31, 32; âmanned Voyager,â
25; Mars Surface Sample Return (MSSR) probe,
28, 29, 31, 32; Mission Module, 14, 25, 26, 27, 61;
and Mariner 2, 12; and Mariner 4, 22, 23; and
ârobot caretakerâ justification, 12, 22, 23
piloted Mars lander, 80; Aeronutronic Mars Excursion
Module (MEM), 15-18, 29, 45, 51; Flyby-Landing
Excursion Module (FLEM) MEM, 29; Flyby-
Rendezvous MEM, 15; Mars Excursion Vehicle
(MEV), 14-15; Mars Landing Vehicle, 85; NAR
MEM, 37-39, 44, 51, 85; NASA STG MEM, 44-45;
SAIC Mars lander, 59; TRW MEM, 20; von Braun
gliders, 1-3, 23
piloted Mars orbiter, 12, 13, 14, 26, 58; see also PH-D
Proposal
Planetary Joint Action Group (JAG), 24-32, 45;
Planetary Exploration Utilizing a Manned Flight
System, 26, 27
Planetary Missions Requirements Group (PMRG)âsee
under NASA
Planetary Report, The, 59
Planetary Society, The, 58, 59, 71, 73, 74; fund early
Mars ISRU research, 56; Mars Declaration, The,
67, 74; Steps to Mars conference, 73, 74
Pluto, 12, 35
post-Apollo space program, 9, 21, 24, 29, 41, 46, 49, 56,
87; see also Apollo Applications Program
post-Saturn rocket, 7, 9, 15, 21, 33; see also Nova rocket
Pravda
, 74
Presidentâs Science Advisory Committee (PSAC), 30,
35, 42, 49, 74; The Next Decade in Space, 49; The
Space Program in the Post-Apollo Period, 30
Progress spacecraft, 84
Project Horizon, 11
Project Pathfinder technology development program,
70, 77, 78
Proton rocket, 74
Pueblo incident, 39
Quayle, Dan, 77, 78, 81, 82, 84
radiation, 6, 13, 14, 19, 23, 58, 62, 64, 71, 85, 90, 97;
spacecraft radiation shelter, 6, 8, 13, 21, 27, 51,
72, 73, 85
radioisotope power unit, 13, 21
Rall, Charles, 63
Rand Corporation, 19, 82, 85
Ranger program, 12, 14, 22, 53
Reagan, Ronald, 60, 67, 68, 69, 73, 74; and âKennedy-
style declaration,â 77
Redstone Arsenal, 7
Redstone missile, 7
Republican, 40, 41, 46, 60, 83
Ride, Sally, 69, 70, 71, 73, 78, 91
Ride Reportâsee Leadership and Americaâs Future in
Space
RL-10 engine, 22
Roberts, Barney, 61, 62, 63
Rocket Team, The, 1
Roentgen Equivalent Man (REM), 6
Rogers Commission, 69
rover, 51, 53, 56, 58, 59, 74, 86, 90, 92, 93, 94, 97; and
âwalk-backâ limit, 51; see also tractor
Ruppe, Harry, 11, 15, 21, 22
Ryan, Cornelius, 2
Sabatier, Paul, 55
Sabatier process, 55, 90
Sagan, Carl, 58, 73, 74; see also Mars Pathfinderâ
Sagan Memorial Station
Saturn (planet), 53
Saturn rocket, 7, 8; âBig Shot,â 33; Saturn C-5, 13, 15;
Saturn I, 7; Saturn IB, 7, 11, 22, 36; Saturn V, 11,
13, 15, 21, 22, 28, 29, 31, 33-37, 39-41, 44, 48, 49,
52, 57, 74, 89, 91; Saturn V launch description, 33
Saturn rocket modifications: Improved Saturn V,
26, 27; MS-IVB stage, 26, 27, 28, 31; S-IIB stage,
22; uprated Saturn V, 36
Schaefer, Ryan, 89
Science Applications International Corporation (SAIC),
59, 68, 71, 72, 73, 81, 90; Piloted Sprint Missions
to Mars, 71, 72; split/sprint mission mode, 71-73, 90
Science in the USSR, 84
Schachter, Oscar, 2
Schmitt, Harrison, 60, 61, 74, 84; âChronicles Plan,â 60;
âMars 2000 Millennium Project,â 61
Schriever, Bernard, 67
Sea of Tranquillity, 2, 22, 43; Tranquillity Base, 43
Seaborg, Glenn, 42, 44
Seamans, Robert, 25, 40, 42, 44, 46, 85
Semyonov, Yuri, 74, 84
Senate, 34, 52, 84; Appropriations Committee, 31, 32,
40; Foreign Relations Committee, 47; Majority
Leader, 34; Space Committee, 34, 40, 46, 68
Shepard, Alan, 6
Shuttle-derived vehicle, 61, 62, 63, 79, 96, 97; Ares rocket,
89-91; Shuttle-Z, 80
Singer, S. Fred, 58, 60
Sky & Telescope, 15
Smith, Margaret Chase, 46
148
Monographs in Aerospace History
Index
Smithsonian Institution: Air & Space Smithsonian, 63;
National Air and Space Museum, 77
Sohn, Robert, 19, 20, 90
Sojourner rover, 95, 98
solar array, 27, 28, 51, 58, 60, 68, 74, 85, 96, 97
solar flare, 6, 23, 27, 51, 64
Soviet Academy of Science, 61
Soviet Union, 4, 6, 34, 57, 73, 74, 75, 84, 85, 95
Soyuz spacecraft, 85
Space Cooperation Agreement, 73, 74
Space Exploration Initiative (SEI), 73, 77-87, 89, 91, 95;
America at the Threshold, 85, 87; cost estimate,
79-80; 90-Day Study, The, 77-82, 87, 89, 93, 95;
Outreach Program, 82, 83, 85, 87; Synthesis
Group (Stafford Group), 82, 85, 86, 87, 89, 91, 93
Space News, 82
Space Nuclear Propulsion Office (SNPO), 34, 35
Space Shuttle, 42-46, 48-52, 55, 59, 60, 62, 63, 67, 68, 69,
70, 73, 75, 79, 80, 83, 85; Challenger, 67, 68, 69, 70,
74, 75; Columbia, 57, 60; Discovery, 75; External
Tank (ET), 57, 80, 89; launch description, 57;
âmyth of an economic Shuttle,â 67; orbiter, 57, 67;
Orbiter Maneuvering System (OMS), 57; Solid
Rocket Boosters (SRBs), 57, 67, 80, 89; Space
Shuttle Main Engines (SSMEs), 57, 80, 89; Space
Transportation System (STS), 49; Spacelab, 57,
59; STS-1, 57, 60; STS-4, 60; STS-26, 75; STS-27,
75; STS-51L, 67; source of technology for Mars
missions, 50, 51, 57, 58; see also Shuttle-derived
vehicle
Space Station, 1, 2, 3, 6, 12, 24, 40, 42, 43, 44, 45, 46, 49
57, 59, 60, 61, 62, 63, 64, 67, 68, 69, 70, 71, 72, 74,
77, 81, 84, 85, 86, 91, 95; Dual Keel, 67, 68, 79, 84;
International Space Station, 85, 94; Mir, 74, 84,
85; Mir-2, 85; Phase I, 67, 68, 73; Phase II, 67, 70,
84; Salyut, 60, 61, 73; Skylab, 24, 48; Space
Operations Center (SOC), 60; Space Station
Freedom, 77, 78, 79, 80, 83, 84, 85, 86, 98; space
port versus laboratory, 60, 70; spaceport function
de-emphasized, 60, 83-84; source of technology
for Mars missions, 44, 57-59, 61, 63
space suit, 11, 17, 51, 81, 97, 98
Space Task Group (STG):
progenitor of Manned
Spacecraft Center, 15; charting NASAâs future,
42-46, 48, 49, 52, 68, 69, 78, 89; Americaâs Next
Decades in Space: A Report to the Space Task
Group,
47;
Post-Apollo Space Program:
Directions for the Future, The, 47-48
Space Transportation System (STS)âsee under Space
Shuttle
Spacelabâsee under Space Shuttle
split-sprint mission modeâsee under
Science
Applications International Corporation
split mission architecture, 89
Sputnik 1, 4, 5, 34
Stafford, Thomas, 82, 85, 86, 91
Stanford University, 73, 94
Stever, H. Guyford, 82
Stone, Edward, 94, 95
Stuhlinger, Ernst, 7, 8, 9, 11
Sullivan, Kathy, 67
Surveyor program, 14, 53; Surveyor 4, 93
Symposium on the Manned Exploration of Marsâsee
under American Astronautical Society
telescope, 2, 3, 4, 11, 27, 28, 53
Tet Offensiveâsee under Vietnam
Texas A&M University, 71, 83
Tharsis Plateau, 53
Time, 74
Titov, Vladimir, 74
Titus, R. R., 29
Townes, Charles, 25, 41
tractor, 2, 3
Trafton, Wilbur, 94, 95
Traxler, Robert, 83
Truly, Richard, 77, 78, 79, 80, 82, 86
TRW Space Technology Laboratory, 19, 20
UMPIRE, 18-19, 21, 55
Unfavorable Manned Planetary Interplanetary
Roundtrip Expeditionsâsee UMPIRE
United Aircraft Research Laboratories, 29
United States (U.S.), 1, 6, 12, 13, 22, 24, 31, 33, 34, 39,
43, 44, 47, 57, 58, 61, 67, 68, 73, 74, 75, 83, 84, 86,
93, 98
United States Air Force, 15, 34, 42, 85; Edwards Air
Force Base, 58
United States Army, 4, 7; Army Ballistic Missile Agency
(ABMA), 1, 7, 11; Corps of Engineers, 81; see also
U.S. governmentâDepartment of Defense
United States government:
Central Intelligence
Agency (CIA),
6,
61,
74;
Department of
Agriculture, 67; Department of Commerce, 67;
Department of Defense, 5, 39, 49, 82, 83, 85;
Department of State,
67;
Department of
Transportation, 67, 85; NACA (National Advisory
Committee on Aeronautics), 5, 19; National
Science Foundation, 67, 82; see also Atomic
Energy Commission; Congress; Department of
149
Index
Humans to Mars: Fifty Years of Mission Planning, 1950â2000
150
Monographs in Aerospace History
Energy; NASA; United States Air Force; United
States Army; White House
University of Arizona, 67
University of Illinois Press, 1
University of Texas, 71
urban riots, 29, 31, 32
Utopia Planitia region, 54
V-2 missile, 1, 7
Valles Marineris, 53
Van Allen Radiation Belts, 6, 8, 58, 97, 98
Varsi, Giulio, 55, 56, 90
Vastitas Borealis region, 17
Venus, 12, 13, 20, 23, 26, 32, 37, 45, 53, 58, 62, 80
Vietnam, 24, 29-31, 39, 49; Tet offensive, 39
Viking, 32, 35, 48, 53-57, 60, 68, 74, 93, 95
von Braun, Wernher, 1-4, 6, 7, 11, 13, 19, 21, 23, 33, 42-
48, 98; career apogee, 44; Das Marsprojekt, 1, 3;
The Exploration of Mars, 3; The Mars Project, 1,
2, 7, 11, 19
Vostok 1, 6
Voyager Mars/Venus program, 24-26, 29-32, 35; as vic-
tim of piloted flyby planning, 32
Wallops Island, 60
Washington Evening Star, 41
Washington Post, 74
Webb, James, 24, 31, 39, 40, 41
weightlessness, 1, 3, 13, 28, 58, 64, 71, 84, 90
Whipple, Fred, 2
White, Ed, 30
White House, 29, 32, 35, 39, 40, 47, 49, 52, 60, 67, 68, 69,
73, 77, 78, 81, 83; Budget Bureau, 21, 24, 29, 35,
40, 42, 48; National Space Council, 24, 77, 78, 79,
81, 84, 86; Office of Management and Budget
(OMB), 48, 49, 52, 69, 77; Office of Science and
Technology Policy, 67; see also individual
Presidents;
Presidentâs Science Advisory
Committee (PSAC)
Wilkening, Laurel, 67
Wood, Lowell, 81
Working Group on Extraterrestrial Resources (WGER),
55
Yeager, Chuck, 67
Yeltsin, Boris, 85
Young, John, 57
zero gravityâsee weightlessness
Zubrin, Robert, 89, 90, 91
Zuckert, Eugene, 15
Index
151
All monographs except #1 are available by sending a self-addressed 9 x 12â envelope for each monograph with
appropriate postage for 15 ounces to the NASA History Office, Code ZH, Washington, DC 20546. A complete list-
ing of all NASA History Series publications is available at http://history.nasa.gov/series95.html on the World
Wide Web. In addition, a number of monographs and other History Series publications are available online from
the same URL.
Launius, Roger D., and Aaron K. Gillette, compilers. Toward a History of the Space Shuttle: An Annotated
Bibliography. Monograph in Aerospace History, No. 1, 1992. Out of print.
Launius, Roger D., and J.D. Hunley, compilers. An Annotated Bibliography of the Apollo Program. Monograph in
Aerospace History, No. 2, 1994.
Launius, Roger D. Apollo: A Retrospective Analysis. Monograph in Aerospace History, No. 3, 1994.
Hansen, James R. Enchanted Rendezvous: John C. Houbolt and the Genesis of the Lunar-Orbit Rendezvous
Concept. Monograph in Aerospace History, No. 4, 1995.
Gorn, Michael H. Hugh L. Drydenâs Career in Aviation and Space. Monograph in Aerospace History, No. 5, 1996.
Powers, Sheryll Goecke. Women in Flight Research at NASA Dryden Flight Research Center from 1946 to 1995.
Monograph in Aerospace History, No. 6, 1997.
Portree, David S. F., and Robert C. Trevino. Walking to Olympus: An EVA Chronology. Monograph in Aerospace
History, No. 7, 1997.
Logsdon, John M., moderator. Legislative Origins of the National Aeronautics and Space Act of 1958: Proceedings
of an Oral History Workshop. Monograph in Aerospace History, No. 8, 1998.
Rumerman, Judy A., compiler. U.S. Human Spaceflight, A Record of Achievement 1961-1998. Monograph in
Aerospace History, No. 9, 1998.
Portree, David S. F. NASAâs Origins and the Dawn of the Space Age. Monograph in Aerospace History, No. 10, 1998.
Logsdon, John M. Together in Orbit: The Origins of International Cooperation in the Space Station. Monograph in
Aerospace History, No. 11, 1998.
Phillips, W. Hewitt. Journey in Aeronautical Research: A Career at NASA Langley Research Center. Monograph in
Aerospace History, No. 12, 1998.
Braslow, Albert L. A History of Suction-Type Laminar-Flow Control with Emphasis on Flight Research. Monograph
in Aerospace History, No. 13, 1999.
Logsdon, John M., moderator. Managing the Moon Program: Lessons Learned Fom Apollo. Monograph in Aerospace
History, No. 14, 1999.
Perminov, V. G. The Difficult Road to Mars: A Brief History of Mars Exploration in the Soviet Union. Monograph in
Aerospace History, No. 15, 1999.
Humans to Mars: Fifty Years of Mission Planning, 1950â2000
NASA History Monographs
152
Monographs in Aerospace History
Tucker, Tom. Touchdown: The Development of Propulsion Controlled Aircraft at NASA Dryden. Monograph in
Aerospace History, No. 16, 1999.
Maisel, Martin, Giulanetti, Demo J., and Dugan, Daniel C. The History of the XV-15 Tilt Rotor Research Aircraft:
From Concept to Flight. Monograph in Aerospace History, No. 17, 2000 (NASA SP-2000-4517).
Jenkins, Dennis R. Hypersonics Before the Shuttle: A Concise History of the X-15 Research Airplane. Monograph in
Aerospace History, No. 18, 2000 (NASA SP-2000-4518).
Chambers, Joseph R. Partners in Freedom: Contributions of the Langley Research Center to U.S. Military Aircraft
of the 1990s. Monograph in Aerospace History, No. 19, 2000 (NASA SP-2000-4519).
Waltman, Gene L. Black Magic and Gremlins: Analog Flight Simulations at NASAâs Flight Research Center.
Monograph in Aerospace History, No. 20, 2000 (NASA SP-2000-4520).
NASA History Monographs