Space Colonization—Benefits for the World 

W. H. Siegfried 

The Boeing Company, Integrated Defense Systems, Huntington Beach, California 92647 

714-896-2532, william.h.siegfried@boeing.com 

Abstract

. We have begun to colonize space, even to the extent of early space tourism. Our early Vostok, Mercury, 

Gemini, Apollo, Skylab, Spacehab, Mir and now ISS are humankind’s first ventures toward colonization. Efforts are 
underway to provide short space tours, and endeavors such as the X-Prize are encouraging entrepreneurs to provide new 
systems. Many believe that extended space travel (colonization) will do for the 21st century what aviation did for the 20th.  
Our current concerns including terrorism, hunger, disease, and problems of air quality, safe abundant water, poverty, and 
weather vagaries tend to overshadow long-term activities such as Space Colonization in the minds of many.  Our leading 
“think tanks” such as the Woodrow Wilson International Center for Scholars and the Brookings Institute do not rate space 
travel high on lists of future beneficial undertakings even though many of the concerns listed above are prominently 
featured. It is the contention of this paper that Space Colonization will lead toward solutions to many of the emerging 
problems of our Earth, both technological and sociological. The breadth of the enterprise far exceeds the scope of our 
normal single-purpose missions and, therefore, its benefits will be greater. 

COLONY—“A BODY OF PEOPLE LIVING IN A NEW TERRITORY BUT  

RETAINING TIES WITH THE PARENT STATE” 

It took 100,000 years for humans to get inches off the ground. Then, astonishingly, it took only 66 years to get from 
Kitty Hawk to the Moon. We have sent probes out of our solar system and have begun expoloration of our universe. 
Both robotic and human exploration of space is well underway and we have begun to colonize space, even to the 
extent of early space tourism. Our early Mercury, Gemini, Apollo, Skylab, Spacehab, Mir, and now ISS are 
humankind’s first ventures toward colonizing space. Efforts are underway to provide short space tours and 
experiences and endeavors such as the X-prize are encouraging entrepreneurs to provide new systems. Many believe 
that space travel (colonization) will do for the 21st century what aviation did for the 20th. For purposes of definition, 
space colonization includes space-based operations in Earth orbit, in transit, and on planetary surfaces; robotic, 
automated, and human space exploration and data needs; tourism; development of space colonies and Mars; and 
other planetary terraforming activities. But why should we persevere in the face of terrorism, hunger, disease, and 
problems of air quality, safe abundant water, poverty, and weather vagaries to name a few of our current problems? 

Recently, a “Global Foresight Workshop” was convened by the Woodrow Wilson International Center for Scholars, 
Foresight, and Governance Project (Smitherman, 2002). Organizers solicited goals from key agencies and 
organizations across the country and internationally through solicitations from United Nations University via the 
“Millennium Project.” One hundred goals were submitted, which were then combined and condensed to 46 for 
workshop consideration. The top five goals based on high-ranking for overall global importance were as follows: 

1.  Provide clean food and water 

2.  Provide clean and abundant energy 

3.  Eliminate all major diseases 

4. End 

slavery 

globally 

5.  Provide universal health care 

Findings such as these are consistent with a Brookings Institute study that asked a group of academic historians, 
political scientists, sociologists and economists to forecast the most important achievements for the next 50 years. In 
this study, space endeavors such as exploration or colonization were not on the major list and were ranked low, 
among the least important accomplishments, even though the above goals were featured. 

Although thus not viewed as a beneficial enterprise by many, it is our position that Space Colonization can help lead 
to solutions to many of the emerging problems of our Earth, such as those listed above, both technical and 
sociological. The breadth of the enterprise far exceeds our normal single-purpose missions and, therefore, its 
benefits are greater. Among the technical attributes of Space Colonization are the potential of developing low-cost, 
nonpolluting energy, enhanced food-production techniques, pollution/waste and water purification, development of 
disease-amelioration techniques, and the development of techniques to help protect Earth from potential meteoroid 
impact hazards (Siegfried, 1996). 

LOW-COST, NONPOLLUTING ABUNDANT ENERGY IS REQUIRED 

FOR SPACE COLONIZATION 

The world population has finally recognized that we are polluting our nest. We are using energy at a prodigious rate 
(Fig. 1) (Siegfried, 1991). There is a demonstrated connection between the cost of energy, its availability and a 
nation’s standard of living. Long-term clean energy sources must be provided to assist not only with our future 
needs, but also with those of all nations’ current requirements. Energy sources are an important part of 
environmental thrusts. Nuclear research is progressing, but it does not promise near-term solutions and developing 

 

 

 

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nations are reaching a plateau of available power. The emerging nations’ need for power must be balanced against 
potential environmental damage from such dangers as fossil fuel emissions (if there were enough fuel available), 
which could be greater than nuclear energy risks. Currently, the United States annually consumes approximately 3 
trillion Kwh’s of electrical energy and, if this rate grows at only 2% per year, by 2050 United States power 
requirements will be around 9 trillion Kwh’s per year. Total world needs, assuming a very low use by developing 
nations (not a conservative estimate) easily exceeds an estimated 20 trillion Kwh’s by 2050. Even with an attendant 
tripling of non-nuclear systems, such as hydroelectric to avoid fossil fuel depletion, nuclear power system generation 
would have to increase by a factor of 6 to meet requirements. This increase in nuclear energy production flies in the 
face of a rising discontent with adverse environmental effects of nuclear waste disposal, where some plants are 
being converted to utilize fossil fuels. A clean renewable source of energy must be found and implemented. Space 
Colonization can lead to solutions to this problem.  

Three potential energy sources are described in Table 1. Helium 3, solar power satellites (SPS), and a lunar (solar) 
power system (LPS) all have significant feedback potential for other commercial applications. A space-based energy 
system would be global in scale and funding and would thus be a challenging goal for macro-engineering 
management to achieve. This management experience would be globally shared and would be utilized for other 
global projects. Robotics and artificial intelligence would also benefit from the use of smart and capable robots to 
autonomously conduct such functions as space assembly and lunar mining and processing. Computer systems would 
be extended in capacity and reliability, energy-transfer technology would be enhanced, and materials research would 
quest for more efficient space systems and learn to utilize in-situ materials. SPS and LPS will require advancement 
in photovoltaic cell technology. This quest can also influence transportation technology because at least one of the 
solutions could lead to more efficient space propulsion. This would reduce travel times and minimize exposure to 
potentially debilitating space environments. 

TABLE 1.

 Space-Based Energy Sources. 

Helium-3 system concept 

■

 

Helium-3 is mined on lunar surface and transported to Earth for use in fusion reactors 

■

 

Deuterium and He-3 fuse cleanly and produce little radiation or waste 

■

 

We estimate that enough He-3 is on lunar surface to satisfy current world energy needs for 

1000 years 

Solar Power Satellite (SPS) 
concept 

■

 

Four to six satellites in geosynchronous Earth orbit transmitting solar energy to the surface 

■

 

10 GW of electric power per satellite 

■

 

Use lunar materials for construction of SPS and transportation system to place in 

geosynchronous orbit 

Lunar Power System (LPS) 
concept 

■

 

LPS will collect solar energy on lunar surface and transmit back to Earth 

■

 

LPS used first to power lunar base to demonstrate technology 

003341.1 

SPACE COLONIZATION MUST HAVE LOW-WATER, LOW-PESTICIDE PLANT 

GROWTH AND WASTE AND WATER PURITY CONTROL 

Two of the items listed here represent major concerns of most developed nations and are emerging concerns in 
developing nations. A technological revolution is needed to address food shortages to allow adequate nutrition for 
our exploding world population in concert with ever-growing water shortages, and a growing realization that our 
current pesticide methods are polluting our planet. While previous short-duration human space programs have 
depended on open-loop life support systems, Space Colonization cannot. Development of a closed-cycle bio-
regenerative controlled ecological life support system (CELSS) would lead to world benefits. Areas of CELSS 
development are listed in Table 2. Many long-term (and pressing short-term) world problem solutions can be 
approached by reaching for the stars. For example, Shimizu Corporation is most interested in bio-regenerative 
systems as a path toward solution of Tokyo’s waste management problems. 

SPACE COLONIZATION MAY LEAD TO HUMAN PHYSIOLOGY,  

AGING, AND DISEASE AMELIORATION 

Many current human problems are the result of failures of the body’s natural immune system. We can diagnose 
many of these problems and have made great strides in ameliorating the symptoms, but to date, understanding 
immune system function and enhancement is seminal. Both United States and Russian long-term space missions 
have induced similar red blood cell and immune system changes. Hematological and immunological changes 
observed during, or after, space missions have been quite consistent. Decreases in red cell mass were reported in 
Gemini, Apollo, Skylab and Soyuz, and Mir programs—probably due to diminished rates of erythrocyte production. 
Space flight at microgravity levels may produce changes in white blood cell morphology and a compromise of the 
immune system. Skylab studies indicated a decrease in the number of T lymphocytes and some impairment in their 
function. Certain United States and Russian findings suggest that space flight induces a transient impairment in 
immune system function at the cellular level. Space flight offers a clinical laboratory unlike any place on Earth that 
may lead to an improved understanding of the function of the human immune system. Perhaps cures of aging, HIV, 
and other immune function-related illnesses can result from a comprehensive approach to Space Colonization. 

SPACE COLONIZATION CAN HELP PROTECT EARTH FROM ASTEROID AND  

METEORITE HAZARDS (NEAR-EARTH-OBJECT IMPACTS) 

Over the last decade a large mass of evidence has been accumulated indicating that near-Earth-object (NEO) impact 
events constitute a real hazard to Earth. Congress held hearings on the phenomenon in 1998, and NASA created a 
small NEO program. Since 1988, a total (as of 7 August 2002) of some many thousand near-Earth objects (of which 
about 1,000 are larger that 1 km in diameter) have been catalogued that are potentially hazardous to Earth. New 
discoveries are accelerating. In just the last few months, a 2-mile-wide crater was discovered in Iraq dating from 
around 2000 to 3000 B.C. This impact was potentially responsible for the decline of several early civilizations. A 
similar crater was recently discovered in the North Sea. Major events have occurred twice in the last hundred years 
in remote areas where an object exploded near the Earth’s surface bur did not impact (such as in Russia). If either of 
these events had occurred over a populated area the death toll would have been enormous. Our armed forces are 
concerned that an asteroid strike could be interpreted as a nuclear attack, thus triggering retaliation. What higher 
goals could Space Colonization have than in helping to prevent the destruction of human life and to ensure the future 
of civilization? The odds of an object 1 km in diameter impacting Earth in this century range between 1 in 1,500 and 
1 in 5,000 depending on the assumptions made. A 1-km-diameter meteoroid impact would create a crater 5 miles 
wide. The death toll would depend on the impact point. A hit at Ground Zero in New York would kill millions of 
people and Manhattan Island (and much of the surrounding area) would disappear. The resulting disruption to the 
Earth’s environment would be immeasurable by today’s standards. A concerted Space Colonization impetus could 

TABLE 2.

 Critical CELSS Development Areas. 

Plant growth in controlled 
environment 

■

 

Select crop plants for nutritional value and productivity 

■

 

Optimize and control plant growth response 

■

 

Develop support systems to allow growth in closed chambers 

Waste processing and nutrient 
recovery 

■

 

Develop energy-efficient waste processor to convert plant and human waste into plant 

nutrients and water 

■

 

Develop biomass processor to convert some portion of inedible plant materials into 

dietary supplements 

Atmosphere revitalization 

■

 

Develop technology for makeup nitrogen generation 

■

 

Remove CO

2

 reduction by-products 

■

 

Improve trace contaminant control and monitor 

Plant growth in reduced or 

microgravity 

■

 

Study crop plant productivity with microgravity as worst case 

■

 

Determine ability of support systems to function in microgravity 

■

 

Perform multiple-generation studies in space radiation flow-g environment 

Plant growth in controlled 
environment 

■

 

Develop laboratory system to investigate microbial interactions and toxicology 

■

 

Determine control strategies to provide stable life support system 

Water management 

■

 

Eliminate urine pretest chemicals 

■

 

Regenerate or eliminate post-treatment filter and sorbent beds 

■

 

Improve quality monitoring 

003342.1 

provide platforms for early warning and could, potentially, aid in deflection of threatening objects. NEO detection 
and deflection is a goal that furthers international cooperation in space and Space Colonization. Many nations can 
contribute and the multiple dimensions of the challenge would allow participation in many ways—from telescopes 
for conducting surveys, to studies of lunar and other planet impacts, to journeys to the comets. The Moon is a natural 
laboratory for the study of impact events. A lunar colony would facilitate such study and could provide a base for 
defensive action. Lunar and Mars cyclers could be a part of Space Colonization that would provide survey sites and 
become bases for mining the NEOs as a resource base for space construction. The infrastructure of Space 
Colonization would serve a similar purpose to the solar system as did that of the United States Interstate Highway 
system or the flood control and land reclamation in the American West did for the United States development. In 
short, it would allow civilization to expand into the high frontier. 

SPACE COLONIZATION WILL HAVE MANY BENEFICIAL ASPECTS 

A complete list of potential world benefits from Space Colonization is lengthy, even when confined to technological 
items. Included are access to space resources that include quantities of almost every resource we have on Earth 
except fossil fuels; an improved understanding of the complex systems that comprise our climate; conducting 
experiments in chemistry, biology, physiology, and even sociology that cannot be conducted here on Earth; and 
developing new technologies for use on Earth. All are the bounty of Space Colonization. 

There are also many sociological benefits of Space Colonization. We must remember that such an endeavor cannot 
be implemented by one any agency or single government. A world policy would be needed. In the United States, the 
combined efforts of NASA, DOE, DOI, DOT, DOC, and others would be focused in addition to our broad industrial 
base and the commercial world. It should be noted that the eventual space tourism market (tapping in to the world 
annual $3,400 billion market or the United States $120 billion per year “adventure travel” market) (Reichert, 1999) 
will not be based on the work of isolated government agencies but, rather, evolve from a synergistic combination of 
government, travel industry, hotel chains, civil engineering, and, yes, a modified version of industry as we know it 
today. The change in emphasis from our present single-objective missions to a broadband Space Colonization 
infrastructure will create employment here on Earth and in space for millions of people and will profoundly change 
our daily life on Earth. This venue, initiated by short suborbital followed by short orbital and then orbital hotel stays 
(Collins, 2000) has already begun with brief visits to the ISS. Once systems evolve that can reduce the cost of a 
“space ticket” to some $10,000 to $50,000 US, the market will grow. Fig 2 is typical of studies on space tourism 
passengers that could be expected vs. costs of the trip. 

Space Colonization Will Influence the Sociology of Our World 

Included herein are jobs and education incentives and potential synergistic effects of Space Colonization. As a 
model, we will utilize United States data because similar worldwide data are not available. The general effect of 
civil space on the United States economy is summarized in Table 3, based on data from 1990. Over and above the 
direct benefits received by the states having major aerospace industry, there are indirect benefits to all states, for 
people buy goods and services (such as cars) with the money they earn. This can range from 4-to-1 ratios in the 
major states benefited to as high as 10-to-1 ratios in states such as Michigan, Oklahoma, and Kentucky. The 
numbers here are the number of dollars realized for every dollar spent. 

Past Spin-Offs 

A summary of spin-offs and feedback from civil space programs is shown in Table 4. These data are further 
augmented by information shown in Table 5, which contains an estimate of the dollar value (in millions of 1990 US 
dollars) of technological pull-throughs subdivided by end use. The data were generated by the Chapman Group in 
the late 1980’s. These data are derived from space programs that were not specifically structured to produce product 
benefits. Table 6 shows examples of critical technologies with potential commercial value as determined by the 
NASA Science Technology Council. 

 

TABLE 3.

 How Does the United States Economy Relate to Civil Space? 

■

 

Method of measurement 

■

 

Direct: Those states awarded NASA procurement dollars 

■

 

Indirect: Those states producing goods and services required by 

recipients of NASA procurement awards 

■

 

Number of jobs created: White and blue collar 

■

 

Highlights of FY90 $12.3 billion procurement 

expenditures created, directly and indirectly 

■

 

237,000 jobs in private industry 

■

 

$23.2 billion in total industry sales 

■

 

$500 million in corporate-funded R&D 

■

 

$2.4 billion in corporate profits 

■

 

$7.4 billion in federal, state, and local tax revenues 

■

 

States benefiting most from United States space 

program are those with large aerospace 
industries, but other states also benefit 
significantly 

■

 

Arkansas, Oklahoma, Illinois, and Michigan show high ratios of 

gain per NASA dollar spent in the United States 

■

 

Many industries other than aerospace benefit 

from NASA procurement as indicated by high 
economic multipliers 

■

 

Only 17% of jobs created fall in engineering and science categories 

003343.2 

 

TABLE 4.

 What Were Past Spin-Offs and Feedback from Civil Space? 

■

 

Over 32,000 spin-offs, NASA does not 

accurately track dollar value 

■

 

Estimated dollar value: $10 to $100 billion 

■

 

Most important spin-off: United States 

aerospace industry still No. 1 

■

 

One of few United States industries with close government and 

industry cooperation in R&D 

■

 

DOD and DOE are major parts of it all 

■

 

Difficult to point to one factor–perhaps total NASA/DOD/ DOE 

budget 

■

 

Second most important spin-off: technical and 

practical knowledge of what can and should be 
done in space–how space and Earth relate 

■

 

Weather satellites, Earth sciences, and natural disaster monitoring 

■

 

Third most important spin-off: specific 

hardware and software 

■

 

Almost all small items, individual dollar values are not large 

■

 

NASA tracks and documents many through Technical Utilization 

and Patent Office 

003344.1 

             

 

 

 

  

 

 

 

 

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Education 

Problems within the education program in the United States have been analyzed many times. Rising illiteracy, 35% 
of all scientist and engineers being foreign born, and the 50% or higher foreign doctorate candidates who return to 
their country of origin after receiving degrees are examples. United States science and engineering schools are 
recognized throughout the world for their standards of excellence, but the number of United States students is 
declining based on a decreasing interest by the younger generation in the sciences and engineering. We must 
encourage young students to select engineering and science for studies as is happening in the rest of the world. 
Space Colonization can provide that stimulus. During the Apollo program, as NASA spending increased, so, too, did 
the number of doctorates received (Fig. 3). When NASA spending decreased following the Apollo program, so did 
the number of doctorates received a few years later (Collins, 2000). This time lag occurred because many students 
were well on their way to achieving their degrees. Once it was clear that funding and federal support had been 
reduced, the student population plummeted. We now face the prospect of many of the people trained in the sciences 
reaching retirement. Where are the replacements? A long-term worldwide commitment to Space Colonization could 
help. We must convince our present elementary school students to commit to science and engineering for these are 
the keys to our future. 

TABLE 5.

 Dollar Value of Technical Pull-Throughs (in Millions). 

End Use Description 

No. of Cases 

Cases with 

Sales 

Savings Sales 

Benefits 

Savings 

Realized 

Total 

Communication and Data Processing 51 32 171,007 

51,964 

222,971 

Energy 30 

13 

203,500 

15,613 

219,113 

Industrial (manufacturing and processing) 170 

107 

5,767,649 

67,837  5,835,486 

Medical 61 

31 

2,003,036 

30,613 

2,033,649 

Consumer Products 

24 

18 

1,278,294 

524 

1,278,818 

Public Safety 

27 

16 

347,888 

555 

348,443 

Transportation 40 

18 

9,887,865 

116,623 

10,004,488 

Environmental 16 

11 

16,962 

21,788 

38,750 

Other 22 

13 

1,654,989 

10,232 

1,665,221 

Total 441 

259 

$21,331,190 

$315,749 

$21,646,939 

003345.1 

TABLE 6.

 NSTC–Critical Technologies with Commercial Applications. 

Area Technology 

Elements 

Adaptive automation 

■

 

Artificial intelligence, expert systems, neural networks, nonlinear dynamics and 

control, sensing and perception, human factors (man and machine interface), 

knowledge representation and acquisition, fuzzy logic networks 

Information acquisition, 
processing, and display 

■

 

Sensor systems, neural networks, artificial intelligence, expert systems, advanced 

displays, virtual displays, advanced computer systems, algorithm development, 
superconductivity devices 

Transportation 

■

 

Computational methods (fluids and solid mechanics, integrated design), aeronautics 

and space propulsion systems, high-strength and density airframe and engine structural 
materials, adaptive vehicle and system control and operations, composite structure 

Materials 

■

 

Materials and processing: metallics, ceramics, organics, composites; manufacturing 

technologies: processing, automation, quality control; nano-tube structure 

Optical communication and 

photonics 

■

 

Free space optical communications, optoelectronics, optical computer and processors 

Nano-technology and nano-
electronics 

■

 

Semiconductor patterning and etching, nano-sensors, quantum wave effects on 

electronic performance 

Energy generation and 
photovoltaic energy conversion 

electro-chemical systems 

■

 

Batteries and fuel cells, power management, Stirling power conversion, space 

environmental effects, electrophysics, solar concentration, heat receivers, and 

radiation 

NSTC: NASA Science Technology Council 

003346.1 

Intangible Benefits 

Aside from the more demonstrable returns that would come from Space Colonization, there are a host of intangible 
benefits (U.S. Office of Management and Budget, 2000; Mankins, 2001; Mankins, 1997; Siegfried, 2000a; 
Siegfried, 1999). Mankind has always been goal-driven. The accessibility of journeys to space destinations could 
become a great motivational factor to the general population and a goal for emerging societies (Koelle, 2002). It 
could become a new commercial industry similar to the explosive growth of travel and adventure trips spawned by 
the jet age. We could expand our living space, create at least a second home for Earth-based life forms through 
development of lunar colonics and, eventually, perhaps terraforming Mars. We can potentially sublimate some of 
our ethnic strife in a common reach to the universe. We will better understand our Earth’s environment and 
evolutionary history and rekindle the spirit of adventure that we experienced during the frontier days. Space 
Colonization will benefit from burgeoning technology here on Earth but will also spawn the creation of as-yet-
undreamed leaps. It could lead to potential storage or disposal venues for waste material and, by its very nature, 
provide the impetus for whole new generations of transportation, housing, and environmental control systems. The 
development of low-cost access systems will spawn flight rates similar to our terrestrial tourist frequencies and, 
coupled with the development of new space businesses and a space infrastructure, will implement humankind’s 
expansion throughout space. It has been 30 years since we left our Moon. It is time to return, this time to stay 
(Siegfried, 1997; Siegfried, 2001; Siegfried, 2000b). 

  NASA Budget and Technical PhDs.

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SUMMARY 

Space Colonization will become an integral part of our 21st century global future. Its effects will be analogous to the 
great changes that the aviation industry catalyzed in the past century. Many of the needs of the Earth’s burgeonizing 
population can be ameliorated by the science and technology emanating from a broad endeavor to reach for the stars. 
Establishing broad new goals will provide motivation for our young. Formation of the colonization industry will 
provide many jobs and may potentially serve to sublimate ethnic strife. As the adventure travel industry here on 
Earth has grown through provision of adventure, drama, mystery, heroism, and hope for the future, so too will Space 
Colonization provide value to humankind. 

REFERENCES 

Collins, P., “Space Hotels—Civil Engineering’s New Frontier,” Advances in Civil Engineering, 4th International 

Congress, Nov. 2000. 

Koelle, H.H.,  “Modeling Space Tourism,” Institute of Aeronautics and Astronautics, University of Berlin, May 

2002. 

Mankins, J., “General Space Travel and Tourism,” Volume 2, Workshop Proceedings, Feb. 1997. 
Mankins, J., “The Exploration and Development of Space—The ISS and Beyond,” NASA Headquarters, 2001. 
Reichert, M., “The Future of Space Tourism,” 50th International Astronautical Congress, Amsterdam, Netherlands, 

Oct 1999. 

Siegfried, W.H., “Return to the Moon, A commercial Program to Benefit the Earth,” 10th International Space Plans 

and Policy Symposium, Bejing, China, Oct. 1996. 

Siegfried, W.H., and Santa, J., “Use of Propellant From the Moon in Human Exploration of Space,” 50th 

International Astronautical Congress, Amsterdam, Netherlands, Oct. 1999. 

Siegfried, W.H., “Current Views on the use of the Moon in Human Exploration and Development of Space,” AIAA 

Space 2000, Long Beach, Calif., Sept. (2000a). 

Siegfried, W.H., and Willenberg, H.J., “Rationale and Systems Architecture for a Near-Term Lunar Return,” 51st 

International Astronautical Congress, Rio de Janero, Brazil, Oct. (2000b). 

Siegfried, W.H., and Willenberg, H.J., “Technology Planning and Commercial Considerations for a Lunar 

Exploration Infrastructure,” AIAA Space 2001 Conference, Albuquerque, NM, Aug. 2001. 

Siegfried, W.H., and Alred, J., “Maximization of Benefits from the Space Exploration Initiative,” International 

Astronautical Federation, Oct. 1991. 

Siegfried, W.H., and Koelle, H.H., “An Approach to Commercial Lunar Basing,” 48th International Astronautical 

Congress, Turin, Italy, Oct. 1997. 

Smitherman, D., Jr, “Government and Industry Issues for Expanding Commercial Markets into Space,” World Space 

Congress, Houston, Texas, Oct. 2002. 

U.S. Office of Management and Budget, “Space Activities of the U.S. Government,” Feb. 2000.