Revolutionary Concepts for
Human Outer Planet Exploration
(HOPE)
Revolutionary Concepts for
Human Outer Planet Exploration
(HOPE)
Pat Troutman
NASA Langley Research Center
Kristen Bethke
Princeton University
February 3, 2003
Pat Troutman
NASA Langley Research Center
Kristen Bethke
Princeton University
February 3, 2003
Presentation for
STAIF-2003
Fission Propulsion Systems for Human Missions
2
Why Look at A Crewed Mission
Beyond Mars?
•
Science ?.......No
•
Flags & Footprints?...........Been There, Done That
•
Tourism ?.......No
•
Our Destiny ? ……….We can argue all day
•
Monoliths and Monkeys?.............
•
Because it is Hard?....... The problem pushes us beyond our Mars
mission “norms” with respect to architecture and technology….
–
“If I can make it there,
I'll make it anywhere”
as sung by Frank Sinatra
3
Analogous Task
Herding Cats
in a room with
Smoke &
Mirrors
where the floor is
covered with
Apples &
Oranges
Human Outer Planet Exploration
Human/Robotic
Surface Systems
Apples-to-Apples
Propulsion
Technology Comparison
Vehicle
Concep
ts
and Co
nfigura
tions
Supporting
Infrastructure
Requirements
Precursor Missions
Trip Tim
e
Radiati
on Exp
osure
Microg
ravity
Bimodal Nuclear Thermal Rocket
Advanced Plasma
Fusion Propulsion
Objective:
Develop revolutionary aerospace systems
concepts for human space exploration of the solar system
beyond Mars orbit and identify critical technology
requirements for the realization of these systems concepts.
JPL – JSC – GRC – MSFC - LaRC
5
2045 + :
•
Earlier robotic probes have identified what appear to
be life forms floating in the oceans of Europa and
embedded in the ice crust near an asteroid impact site
on the surface of Callisto.
•
A crewed expedition is to be sent to the surface of
Callisto to teleoperate the Europa submarine and
excavate Callisto surface samples near the impact
site.
•
The expedition will also establish a reusable surface
base with an ISRU plant to support future Jovian
system exploration
The Mission
6
Mission Requirements
Mission Requirements:
•
Leave from Earth-moon L1
•
Crew of 6 to the Jovian system, minimum of three to the surface of Callisto.
•
Minimum surface stay time of 30 days
•
Maximum crew mission time away from L1 is 5 years
•
Max radiation exposure limits for crew must not be exceeded
•
Maximum of one year accumulated time under 1/8th G during mission for each
crewmember
•
Deploy/construct surface habitat, reusable 3 crew lander and nuclear powered
ISRU plant
•
Tele-operate Europa submarine for 30 days
•
Perform Callisto surface science
7
- Fourth moon of Jupiter: mostly outside of radiation belts
- About the size of the planet Mercury, surface at 1/8 G
- Most heavily cratered place in the solar system
- Covered with ice and asteroid dust
Mission Destination - Callisto
Asgard Impact Structure on Callisto
8
Callisto Precursor Mission
Architecture
Coast: ~5KW
E
For Data &
Controls
Subsequent
NTP Burn
•
Precursor Mission to Callisto including landing and and
exploration <4 years total time.
Earth
Conventional
Launch Vehicle
Nuclear Safe Orbit
NTP Burn
Orbit Callisto
Release Probe
(Pathfinders)
Land On Callisto
•
Propulsive
•
Tether
•
Shock
MITEE B Bimodal NTP System
While on Cruise: ~5KW
E,
On Surface: ~20 KW
E
For Science, Communication & Controls
Ram Manvi;08/22/02
9
HOPE Piloted Vehicle Concepts
“Bimodal” Nuclear
Thermal Rocket (BNTR)
Propulsion
MagnetoPlasmaDynamic
(MPD) Propulsion
Variable Specific Impulse
Magnetoplasma Rocket
(VASIMR) Propulsion
Magnetized Target Fusion
(MTF) Propulsion
10
RASC / HOPE
Space Transportation
Radiation Environment
Earth to Callisto and back (30 day stay)
Daily Dose Equivalent
Accumulated Mission Exposure
55M
55F
45M
35M
45F
25M
35F
25F
• Two year class missions can be supported by 35 to 45 year old crew members who have logged few
hours in space
• Four year class missions will require advanced materials such as hydrogenated nanofibers or crew areas
shielded by hydrogen tanks
11
RASC / HOPE
Space Transportation
Front View
Note differences in color scales
Half full tank
Full tank
Comments on Fuel as
Shielding
• Fuel congregates at
far end of rotating arm
from centrifugal forces
• Locate crew quarters
near outer wall within
the last remaining fuel
• Shielding model must
account for fuel
depletion
• Must be coupled to
variability of space
environment during
mission duration
Effects of Fuel Consumption on
Radiation Exposure Rates
Vehicle Option
P
rop
ul
si
on T
ec
hno
lo
gy
TR
L
T
ec
hno
log
y,
E
ng
in
ee
ring
& P
hys
ic
s I
ssu
es
C
om
pl
ex
ity
o
f V
ehi
cl
es
S
upp
or
ting
In
fr
as
tr
uc
tu
re
Re
qu
irem
en
ts
# V
ehi
cl
es
t
o P
er
fr
om
En
tir
e M
iss
io
n
In
itia
l T
ot
al
V
ehic
le(
s)
D
ry M
ass
a
t
L1
(inc
ludi
ng pa
yl
oa
d)
In
iti
al
T
ot
al
P
ro
pel
lant
Lo
ad
at
L
1
T
ot
al m
as
s
of
all
ve
hic
les
, p
rop
ella
nt
an
d
pa
yl
oa
d init
ially
at
L
1
C
rew t
im
e i
n l
es
s
than
1/
8t
h G
C
rew
T
im
e o
n S
ur
fac
e
Cr
ew
T
rip
T
im
e
A
w
ay
fr
om
L
1
S
pec
ifi
c I
m
pl
us
e
P
er
fo
rma
nc
e Ma
rg
in
C
re
w
S
afe
ty
BNTR Propulsion
4
G
G
R
3
TBD
980+
Y
R
NEP/MPD Propulsion
3
Y
Y
Y
3
558
190
748
30 to 365 Y(120) 4.5 years
8000
Y
Y
NEP/VASIMR Propulsion
2
R
R
Y
3
594
190
784
<30 days
R(32)
5 years 5000-30000
R
G
MTF Propulsion (30 day surface stay)
1
R
Y
Y
1
510
140
650
263
R(30)
<2 years
75000
G
G
MTF Propulsion(180 day surface stay)
1
R
Y
Y
1
550
200
750
212
G(180) < 2 years 75000
G
G
Qualitative Comparison Chart Across Vehicle Concepts
Better than other options
Comparable across options
Not as good as other options
Mission Design
Mission Performance
•
All vehicle options meet mission requirements
HOPE Surface
Operations
Concepts
Surface Operations
• What tasks will need to be completed on Callisto’s
surface?
• What surface systems will exist to enable the tasks to
be completed?
• How will the tasks be distributed among the crew and
the automated systems?
Surface Operations
Driving Assumptions
Technology Assumptions
•
Advanced space suits
- Adequate radiation and cold temperature protection enable up to 15
3-hour
excursions
during a 30-day Callisto surface stay
•
Precision landing capabilities
- Landing target can be reached with an error of no more than 30 meters
•
Autonomous deployment and operation of surface systems
- Habitat, power system, ISRU system, and navigation/communication system can
all be autonomously deployed before crew arrival
•
Prevention of loss during liquid cryogen transfer over 30+ meters
•
Super-cold materials
- Metals that withstand 100 K enable surface vehicle mechanisms
- Structural materials that are flexible at 100 K enable inflatable surface hab
design
•
Brayton nuclear reactor
- Power system can deliver 400 kW
e
power at a mass of 30kg/kW
e
Callisto Surface Operations Visualization
Surface Hab
ISRU
30 m
Reactor
1000 m
RA
DIO
AC
TIV
E
ZO
NE
– N
O
CR
EW
30 m
Crew Lander
TARGET ZONE
FOR SURFACE
HAB AND CREW
LANDER
ICE MOUND
BUILT TO ADD
TO RADIATION
SHIELD
Bulldozer/
Rover
Large Robot
CONCEPT #1
Motherbot
Small Rover
CONCEPT #2
Small
Robots
Surface System Layout
Surface System Architecture
Vehicle and Robotic Systems Concepts
Surface System Architecture
Concept #1 - “Large-scale”
• Large autonomous vehicles
• Multi-task humanoid robots
• Many points of failure on each system
Concept #2 - “Small-scale”
• No large bulldozer of large regolith transporter
• Tasks distributed among many miniaturized, single-
task robots
• Builds on micro-robots of precursor mission’s Phase 2
• Crew Lander
• Surface Habitat
• ISRU Fuel Production Plant
• Brayton Nuclear Reactor Power System
(2 Reactors, ~ 400 kW
e
total)
• Antennas and transmitters
Surface Hab
Crew Lander
Common
Descent
Systems
Surface System Architecture
Common Components
• 2 unpressurized bulldozer/rovers
• 3 “Robonauts”
Surface System Architecture
Large-Scale Concept: Unique Components
• Small rover - transports two crew members
• “Motherbot” platform - deploys and commands robots
• Miniature robots - transport surface material, perform
science tasks
Surface System Architecture
Small-Scale Concept: Unique Components
Small-Scale Concept: Miniature Robots
Surface System Architecture
Crawling
Hovering
Linked as snake
Burrowing
Now that we have all these
robots…
Why humans?
Surface Operations
Surface Operations
Robotics
• All set-up and deployment activities
• All transport of surface material to ISRU plant
• All sample collection
• Scout all EVA routes
Humans
• Outside on surface only for decision-making and analysis
• Interpret information from robots and direct their subsequent actions
• Respond to contingencies
• Select samples
• Discover what they are not told to look for
Surface Operations
Autonomous Set-Up Tasks
•
Deploy reactors and 1000-meter cable to power
ISRU plant and surface hab
•
Build ice mound to function as shielding for
reactors
•
Deploy surface communication system
•
Transport surface material to ISRU plant
•
Test operation of ISRU plant and begin fuel
production; top off tanks in surface hab lander
•
Inflate surface hab
•
Ensure connection of surface hab to
communication system and to reactors via ISRU
Surface Operations
CREW
•
Select sites for traversal
•
Select samples for
retrieval
•
Curate retrieved
samples
•
Examine samples -
biomarker detection
•
Select samples for
return to Earth
•
Monitor crew health
•
Teleoperate robotic
submarines in Europa’s
subsurface ocean
ROBOTICS
•
Map area local to
surface hab and
catalogue field features
•
Prepare surface for
sample collection
•
Collect samples
•
Initial sample analysis in
field
•
Prevent forward and
back contamination of
and by samples
Science Tasks
Conclusion
Concepts and technology requirements to enable
human exploration of the outer planets have been
identified
Roundtrip crewed mission times from 2 to 5 years to the
Jupiter system are achievable given significant
advances in propulsion technologies
Anonymous quote:
“HOPE sees the invisible, feels the intangible and
achieves the impossible”