For NASA Internal Use Only

1
Session 6 Human Mars Exploration Mission
Architectures and Technologies
John Connolly Kent Joosten January 6, 2005
2
Topics

• Human Mars Mission Architectures
• Trade Tree/Past Studies
• Long-stay vs. Short-stay Missions
• Short-stay Mission Example
• Long-stay Mission Example
• Key Findings
• Mission Mode
• In-Space Transportation
• Human Health and Performance
• Advanced Life Support
• Surface Systems
• Space Power
• Cross-cutting Technologies
• Enabling Capabilities and Technologies

3
Major Architectural Considerations
Decision
Impacts

• Mission class
• Short-Stay (opposition class)
• Long-Stay (conjunction class)
• Split mission vs. all-up
• Pre-deploy (split mission)
• All-up (single integrated vehicle)
• Launch vehicle capability
• Existing (maximum 20mt)
• 40-60mt
• 80 mt
• Mars staging location
• Low Mars Orbit
• Libration Points
• None (direct or cycler)
• Power and propulsion choices
• Conventional
• Nuclear
• Crew size

Total mission duration, surface duration, total
energy, crew risk exposure (radiation, gravity),
amount of science performed
Pre-deployment of assets, departure staging
location, multiple departure/arrival windows,
multiple vs one large spacecraft, abort options
Number of launches required, extent and duration
of on-orbit operations
Division of functions across flight elements,
number of elements, energy split, departure
options, abort options, technology options
Total mission mass, technology development risk,
trip time, surface mission duration
Total mission mass, redundancy, amount of science
performed
Propellant mass, consumables mass, total mission
mass, extensibility, redundancy, risk
4
Example Mars Architecture Trade Space
Increasing Performance Decreasing vehicle wet
mass, decreasing trip times, increasing payload,
more challenging mission classes
Nuclear Thermal
Solar Electric / Chemical
Solar Electric
Nuclear Electric
In-Space Propulsion
Chemical
High Thrust
Low Thrust
Hybrid
Mars Capture Aerocapture?
w/o AC
w/ AC
w/o AC
w/ AC
w/o AC
w/ AC
w/o AC
w/ AC
w/o AC
w/ AC
X Config.
X Config.
Mission Type Conjunction (long stay) vs.
Opposition (short stay)
Conj (1952 Von Braun)
Opp
Conj
Opp
Conj
Conj
Opp
Opp
Conj
Conj
Opp
Opp
Conj
Opp
Conj
Opp

X Excessive Mass


X Config.
X Excessive Size
Pre-Deploy Split vs. All-up
Split
All Up
Split
All Up
Split
All Up
Split
All Up
All Up
Split
All Up
All Up




? ? Questionable Feasibility
1988 Mars Expedition 1989 Mars
Evolution 1990 90-Day Study 1991
Synthesis Group 1995 DRM 1 1997 DRM 3
1998 DRM 4 1999 Dual Landers 1989
Zubrin, et.al 1994-99 Borowski, et.al 2000
SERT (SSP) 2002 NEP Art. Gravity
Local Resource Utilization?
w/o ISRU
w/ ISRU
w/o ISRU
w/ ISRU
w/o ISRU
w/ ISRU







Assumptions not necessarily consistent
5
Human Mars Mission Architectures

• Mission Mode Long-stay vs. Short-stay
  Operational Issues
• Microgravity Reconditioning
• Global Dust Storms
• Systems failure/repairs
• Reaction to unexpected findings
• Surface system reliability
• Flight system reliability
• Surface system investment vs. time/revisits

6
Example Short-Stay Missions

• Typically referred to as opposition class
  missions
• Characterized by
• High-propulsive requirements
• Large variation in energy requirements across
  mission opportunities
• Venus swing-by or deep-space Maneuvers
• Close perihelion passage
• Short outbound and long inbound transits
  separated by short surface stay
• Short to long total mission durations
• Majority (90) of crew time spent in deep-space
  environment

Depart Mars 1/25/32
Arrive Earth 11/28/32
Depart Earth 2/6/31
Arrive Mars 12/16/31
Example Short-Stay Mission
7
Example Long-Stay Missions

• Typically referred to as conjunction class
  missions
• Characterized by
• Lower-propulsive requirements
• Small variation in energy requirements across
  mission opportunities
• All mission gt 1 Au
• Short transits separated by long-surface mission
• Long total mission durations
• Majority (50) of crew time spent on Mars

Arrive Earth 12/11/20
Arrive Mars 11/7/18
Depart Earth 5/11/18
Depart Mars 6/14/20
Example Long-Stay Mission
8
Mission Energy Comparison
9
Short-Stay Mission ExampleRef 2002 SA NEP
Artificial Gravity Mission

• Characteristics
• Initial missions limited to 18-24 month round
  trip (18 month goal)
• Three months stay in Mars system
• Split mission no Mars-specific cargo sent
  out with crew
• Assembly Orbit Low Earth orbit
• Departure/return point High Earth orbit
• Destination High Mars orbit
• Piloted vehicle stack less than 200 tons initial
  mass
• Rationale
• Stresses interplanetary steering requirements
  (possible Artificial-G concern)
• Stresses inner solar system operating regime
  (0.5-1.5 AU)
• Stresses propulsion performance
• Out of 18-24 month round trip, three months Mars
  stay with no gravity readaptation time required
  may represent good mission productivity
• Split mission maintains destination-independence
  of crew transfer vehicle
• Earths Neighborhood transportation
  infrastructure (XTV) utilized for crew
  delivery/return

10
Mission Overview
gt30 Day Surface Stay
Launch
Landing
Pre-deployed Mars Lander 500 -gt 90,000
km (Elliptical or Circular Orbits)
Heliocentric Flight Earth - Mars
Heliocentric Flight Mars - Earth
Rendezvous/Dock Of Descent/Ascent Vehicle And
Mars Transfer Vehicle
Mars Crew Transfer Vehicle Constant Thrust Power
6 MW Efficiency 60 Isp 4000 sec Mass
Return to Earth 89 mt
Crew Delivery XTV (Possible Emergency Return
Vehicle)
HEO 30,000 gt 90,000 km (Circular Orbits)
Crew Return
Rendezvous/Dock Of Crew XTV and Mars Transfer
Vehicle
LEO (700 km)
On-orbit Construction of Transfer Vehicle
Launch of NEP Transfer Vehicle
Launch Of Crew XTV
Launch for Crew Pickup
Courtesy Jerry Condon/JSC
11
2026 Trajectory Point Design
90,000 km Earth return 16,700 km Mars Parking
Orbit

• Mission Assumptions
• Earth Departure Orbit 700 km altitude
• Earth Return Orbit 90,000 km altitude
• Mars Parking Orbit 16,700 km altitude
• Stay Time in Mars Orbit 70 days
• System Assumptions
• Power 6 MW
• Specific Impulse (Isp) 4000 sec
• Thruster efficiency 60
• Tankage Fraction 5

Escape Earth Spiral for 98.5 days November 7,
2026 Mass after spiral 232.0 mt
Earth
Close Approach to Sun Distance 0.39 AU
Begin Spiral Capture at Mars June 20, 2027
Mass before spiral 160.8 mt
Start at 700 km Earth orbit altitude July 31,
2026 Initial Mass 271.6 mt
Sun
Mercury
Finish capture at Mars July 27, 2027 Spiral for
6.3 days Capture into 16,700 km orbit Mass after
spiral 158.3 mt
Escape Mars Spiral for 6.1 days Sept. 11,
2027 Mass after spiral 155.9 mt
Capture at Earth June 23, 2028 Orbit altitude
90,000 km Spiral for 2.1 days to capture Mass
after spiral 89 mt
Mars
Stay time 70 days in Mars orbit Begin Spiral
Escape of Mars Sept. 5, 2027
Begin Spiral at Earth return July 21, 2028 Mass
before spiral 89.6 mt
Courtesy Melissa McGuire/GRC, Rob Falck/GRC
12
Artificial-Gravity Vehicle

• Continuing serious concerns regarding human
  physiological effects of long-duration
  micro-gravity exposure
• Loss of bone mineral density
• Skeletal muscle atrophy
• Orthostatic hypertension
• Current countermeasures deemed ineffective (in
  particular w.r.t. bone mineral density loss)

• Main Power
• Redundant Reactors
• Redundant Power Conversion
• Reactor Rad Shielding

Zero-G Docking Port
Propellant Tanks

• Control Jets
• Spinup/spindown
• Steering

Control Jets

• Crew Module
• Inflatable Pressure Shell
• Radiation Shielding
• Micrometeoroid Protection
• Life Support
• EVA Support
• Body-Mounted Radiator

• Main Thrusters
• Primary TVC via vehicle pointing

• Main Power Radiators
• Flexible, Deployable

125 m
13
Long-Stay Mission ExampleRef 1998 Reference
Mission Version 4.0

• Charcteristics
• Split mission predeployed surface habitat and
  ascent descent vehicle
• Solar Electric Propulsion concept (NTR and
  Chemical/Aerobrake investigated as options)
• Single round-trip vehicle for interplanetary crew
  transfers to and from Mars
• In-situ resources for fuel and as a level of
  consumables redundancy
• Shuttle derived launch vehicle (80 mt) used for
  LEO transportation
• Principal Results
• Incorporation of a round-trip crew transfer
  vehicle reduces system reliability requirement
  from five to three years, but requires an
  additional rendezvous in Mars orbit
• End-to-end Solar Electric Propulsion vehicle
  mission concept is shown to be a viable concept,
  but vehicle packaging and size remain tall-poles
• Total mission mass estimates for different space
  propulsion options
• Solar Electric Propulsion 467 mt
• Nuclear Thermal Propulsion 436 mt
• Chemical/Aerobrake 657 mt
• High scientific duration (500 days on Mars)
• Minimizes combined Earth-Mars and Mars-Earth
  transit duration and exposure of crew to
  interplanetary environment
• Maximizes reuse of mission elements SEP and
  surface habitat (if desired)
• Vehicle design independent of mission opportunity
  (small variation (10) in vehicle size for every
  Mars opportunity)
• Enables global surface access if desired

14
Mars Long-Stay MissionExample 2 DRM v 4.0
Surface science concentrates on the search for
life. Deep drilling, geology and microbiology
investigations are supported by both EVA and by
surface laboratories.
Habitat lander predeployed on Mars
Trans-Mars injection and Cruise
Transfer to High Earth Orbit

• 2016
• SEP Vehicle
• Ascent/Descent Vehicle
• Surface Habitat

180 day return trip ends with direct entry and
landing.
Trans-Mars injection and Cruise
Ascent/Descent Vehicle aerocapturss into Mars
orbit
Crew lands, spends 500 days on surface in
predeployed Hab. Crew departs in Ascent/Descent
Vehicle
Crew aerocaptures into Mars Orbit, transfers to
Ascent/Descent Vehicle
2018 Crew transit vehicle and SEP
resupply launched
Crew reaches Mars in 6-8 months
Transfer to High Earth Orbit
Ascent Vehicle rendezvous with Crew Transit
Vehicle in Mars Orbit.
Small crew taxi delivers crew to high Earth
orbit
2018 Crew launched
15
DRM 4.0 Vehicles

• Mars Transit Vehicle
• Transports crew from High Earth Orbit (HEO) to
  Mars orbit
• Crew must rendezvous with an ascent/ descent
  vehicle to visit the surface
• Transports crew from Mars orbit back to Earth

• Mars Surface Habitat
• Supports a crew of six for up to 18 months on
  the surface of Mars
• Provides robust exploration and science
  capabilities
• May include an inflatable greenhouse/ laboratory
  module

• Descent/Ascent Vehicle
• Transports six crew from Mars orbit to the
  surface and back to orbit
• Supports six crew for 30-days
• Uses locally produced propellants for ascent

• SEP LEO-HEO Tug
• Solar-electric propulsion enables
  low-consumption, 6-month spiral transit of large
  cargo elements from LEO to HEO
• Spirals back to LEO for re-fueling and re-use
• Not human-rated

• Crew Taxi
• Transports crew from LEO to HEO
• Can be deployed from shuttle, at ISS, or launched
  directly
• Returns to Earth for re-use

16
Key Mission Mode Findings

• The mission design process must properly balance
  human factors, science return, mission
  performance, and mission cost
• Mars missions are characterized by two mission
  types Opposition/short stay (typically 500 day
  round trip) and Conjunction/long stay
  (typically 1000 day round trip).
• The total mass for opposition missions are
  roughly twice that of conjunction missions for
  similar crew sizes/payloads
• One-year round trip Mars missions are possible
  only in very favorable mission opportunities
  (2018, 2033, etc.) even accounting for aggressive
  technology advancements, and thus represent one
  shot approaches.
• Free-return trajectories, with reasonable
  durations, do not exist for Mars missions.
• Pre-deploying of mission assets can be used to
  reduce overall mission mass and provide
  functional redundancy of mission assets (thus
  reducing mission risk).
• Using local planetary resources works best when
  close to the point of manufacture and when
  returning to the same landing site.
• Missions in near-Earth space (Moon, Libration
  Points) can serve as stepping-stones (system,
  technologies, operations concepts) to further
  exploration activities.

• Selecting the best mission mode is a highly
  coupled tradeoff between mission objectives and
  technology choices
• Selecting a mission mode will reduce the number
  of technology development programs that need to
  be supported, and conversely
• Making specific technology choices will eliminate
  some mission mode options.

17
Example Mars Architecture Trade Space
Increasing Performance Decreasing vehicle wet
mass, decreasing trip times, increasing payload,
more challenging mission classes
Nuclear Thermal
Solar Electric / Chemical
Solar Electric
Nuclear Electric
In-Space Propulsion
Chemical
High Thrust
Low Thrust
Hybrid
Mars Capture Aerocapture?
w/o AC
w/ AC
w/o AC
w/ AC
w/o AC
w/ AC
w/o AC
w/ AC
w/o AC
w/ AC
X Config.
X Config.
Mission Type Conjunction (long stay) vs.
Opposition (short stay)
Conj (1952 Von Braun)
Opp
Conj
Opp
Conj
Conj
Opp
Opp
Conj
Conj
Opp
Opp
Conj
Opp
Conj
Opp

X Excessive Mass


X Config.
X Excessive Size
Pre-Deploy Split vs. All-up
Split
All Up
Split
All Up
Split
All Up
Split
All Up
All Up
Split
All Up
All Up




? ? Questionable Feasibility
1988 Mars Expedition 1989 Mars
Evolution 1990 90-Day Study 1991
Synthesis Group 1995 DRM 1 1997 DRM 3
1998 DRM 4 1999 Dual Landers 1989
Zubrin, et.al 1994-99 Borowski, et.al 2000
SERT (SSP) 2002 NEP Art. Gravity
Local Resource Utilization?
w/o ISRU
w/ ISRU
w/o ISRU
w/ ISRU
w/o ISRU
w/ ISRU







Assumptions not necessarily consistent
18
Mars Architecture Mass History
1 1988 Mars Expedition (Chem A/B) 2 1989 Mars
Evolution (Chem A/B) 3 1990 90-Day Study (Chem
A/B) 4 1991 Synthesis Group (NTR) 5 1995 DRM 1
Long Stay (NTR) 6 1997 DRM 3 Refinement (NTR) 7
1998 DRM 4 Refinement (NTR or SEP) 8 1999 Dual
Landers (SEP) 9 2000 DPT/NEXT (NTR or SEP)
ISS _at_ Assembly Complete (470 tons)
19
Key In-Space Transportation Findings

• Investment in space transportation technologies
  can provide significant mass savings (as compared
  to todays chemical propulsion mission)
• Aerobraking 40-45
• In-Situ Resource Utilization 21-25
• High Efficiency In-Space Propulsion 55
• Combined savings can provide up to 68 savings
• Investment in space transportation technologies
  can provide significant reduction in crew
  exposure to the hazards of the deep space
  environment including radiation, zero-gravity,
  and overall mission duration.
• Electric propulsion is a common technology need
  across the Agency. Emphasis should be placed on
  technologies which are evolvable to meet the
  high-power needs of human missions.
• Chemical propulsion is a common technology need
  for lander/ascent vehicles across the Agency.
  Emphasis should be placed on high performance,
  low volume, and robust propulsion to increase
  payload and decrease volume.
• Aeroassist is a common technology need across the
  Agency. Advancement in aeroassist technologies
  are required for missions to the surface of Mars
  (aeroentry) as well as Earth return
• Long-term storage of cryogenic propellants is an
  essential technology
• Automated rendezvous and docking of mission
  elements in low-Earth orbit is needed

• Advanced in-space transportation is an enabling
  element in future human exploration endeavors
• Advances in in-space propulsion should be pursued
  aggressively
• Aeroassist for Mars capture and entry is essential

20
Key Human Health and Performance Findings

• The deep space and planetary surface radiation
  environment, as well as its effect on the human
  body, must be better understood, monitored, and
  mitigating/protective technologies developed.
• The effects of long term exposure to a micro-g
  environment are reasonably understood but no
  mitigating technologies or procedures have been
  found. In addition, the effects of long-term
  exposure to a hypo-g environment are poorly
  understood.
• Development and demonstration of advanced medical
  care, consistent with long term missions and
  risk, has yet to occur. Abort to Earth is not
  always feasible.
• To date, the Bioastronautics community has
  identified 55 risks and approximately 250
  critical questions for a Mars mission, requiring
  approximately 185 studies to resolve
• ISS can be an important testing venue but only if
  the number of individual crew members is
  increased (for statistical significance) total
  duration on-board could be as little as 3 months.
• Ground-based experiments can answer a significant
  number, but not all, of these questions.
• Missions in Near-Earth space can be conducted
  prior to resolving many of these questions.

Basic environmental data (particularly radiation
data) is still required to reduce risk to human
crews. Significantly more testing (both duration
and number of test subjects) in different gravity
environments is required before the first Mars
mission.
21
Key Advanced Life Support Findings

• Closing the life-support air and water loops with
  low expendables is a key leveraging technology
  for long duration human exploration missions
• Current food preservation technology is not
  capable of providing nutritionally viable food
  for the longer mission durations under study.
  Food production technologies under the
  environmental conditions of these missions is not
  developed to the point of being the primary
  source of food.
• Power requirements for both closed loop life
  support and food production can be significant,
  indicating that advanced life support and
  advanced power systems are closely coupled.

Closing the air and water loops is essential to
reduce the total mass of long duration missions
to a reasonable level. Improvements in food
storage technology or production technology are
also needed to reduce overall mass and ensure
crew health.
22
Key Surface Systems Findings

• Short missions (days or weeks) can accomplish
  useful objectives with local surface mobility
  capabilities (extra-vehicular activity suits and
  unpressurized rovers).
• Long surface missions can be accomplished using
  in-situ resource utilization for mission
  consumables (EVA O2, regenerate fuel cell
  reactants, and life support backup)
• A power rich infrastructure for base and mobile
  operations is critical for science and mission
  success
• All missions are significantly enhanced by the
  addition of advanced surface mobility and robotic
  assistance.
• Surface mobility reduces the time spent
  commuting to and from work sites.
• Surface mobility and robotic assistants can
  increase the mass and volume of equipment that
  can be carried to a work site.
• Robotic assistants can offload tasks from humans.
• Advances in EVA systems are required for both
  zero-g and planetary surface applications.
• Reduced maintenance and operational cost
• Improved dexterity and mobility
• Reduced mass and increased durability

• Advanced EVA technologies are enabling for future
  exploration missions that does not currently
  exist
• Zero-g applications
• Planetary surfaces

23
Key Space Power Findings

• Lightweight megawatt-class nuclear power systems
  (1-3 MWe units, 4-8MWe total) enable low-mass,
  fast-transit Mars missions.
• Small nuclear power modules (30 kWe) enable
  extended Mars surface stays and in-situ
  propellant production, as well as being highly
  desirable for overnight stays on the Moon.
• High-power solar power (0.5 2.0 MWe) concepts
  can provide low-mass transportation (cargo tugs)
  for both Near-Earth exploration as well as Mars
  mission departure.
• Solar / fuel cell concepts, with effective dust
  mitigation techniques, can potentially provide
  adequate power for short-stays on Mars. However,
  dust storm solar illumination attenuation may
  be critical factor.
• High energy density mobile power systems
  significantly enhances advanced surface mobility
  and robotic assistance capabilities and science
  objectives
• Energy density provided by advanced regenerative
  fuel cells is necessary for many phases of
  exploration missions (propulsive maneuvers,
  initial operations, etc.)

• Advanced in-space power is an enabling element in
  future human exploration endeavors
• Nuclear power reactors for both in-space
  transportation and surface use
• Low-mass high efficiency fuel cells are needed
  for many mission phases

24
Key Cross-Cutting Technologies Findings

• Utilizing commodities produced from local
  planetary resources (oxygen, water, etc.) can
  provide great mission mass leverage as well as
  risk reduction (functional redundancy)
• Science return can be best achieved through a
  combination of robotic and human exploration
• Reuse of space-based systems can provide
  significant mass leverage, but at the same time
  pose a technology and operational risk
• Remoteness and time delays of deep-space human
  exploration missions necessitates new operational
  approaches and concepts must operate
  differently from past or current modes.

25
Enabling Capabilities/Technologies
Aldridge Commission (6/04)
CRAI Team Assessment (8/03)
NASA Mission Study Findings (89-92)

• Affordable heavy lift capability
• Advanced structures
• High acceleration, high life cycle, reusable
  in-space main engine
• Advanced power propulsion
• Cryogenic fluid management
• Large aperture systems
• Formation flying
• High bandwidth communications
• Entry, descent landing
• Closed-loop life support and habitability
• Extravehicular activity systems
• Autonomous systems and robotics
• Scientific data collection/analysis
• Biomedical risk mitigation
• Transformational spaceport range technologies
• Automated rendezvous docking
• Planetary in situ resource utilization

• Heavy lift
• Advanced structures
• Reusable in-space engines
• In-space power propulsion
• Cryo fluid management
• Large aperture systems
• High-bandwidth communications
• Planetary entry, decent landing
• Environmental control life support systems
• Extravehicular activity systems
• Autonomous systems/robotic
• Science data analysis
• Automated rendezvous docking
• ISRU

• Low-cost heavy lift
• Advanced interplanetary propulsion
• Cryogenic fluids management
• Automated rendezvous docking
• Accurate and safe planetary landings
• Aeroassist
• Health human performance
• Advanced life support
• Advanced habitation systems
• EVA surface mobility
• In-situ consumable production
• Advanced power generation, management storage

Associated with specific mission scientific goals
26
The Value of Technology InvestmentsMars Mission
Example
All Propulsive Chemical

• NOTES
• Results are cumulative and thus trends will be
  different for different technology
  combinations/sequences
• The change between points shows the relative mass
  savings for that particular technology
• 2018 One-Year Round-Trip Mission, Crew of 4,
  Lander pre-deployed

Ì Aerocapture
Ì Advanced Propulsion
Ì Closed Loop Life Support
Ì Advanced Materials
Ì Maintenance Spares
Ì Advanced Avionics
Today
Ref. Johnson Space Center
27
Potential Uses of Space Resources for Robotic
Human Exploration

• Mission Consumable Production
• Propellants for Landers, Hoppers, Aerial
  Vehicles
• Fuel cell reagents for mobile (rovers, EVA)
  stationary backup power
• Life support consumables (oxygen, water, buffer
  gases)
• Gases for science equipment and drilling
• Bio-support products (soil, fertilizers, etc.)
• Feedstock for in-situ manufacturing surface
  construction

• Surface Construction
• Radiation shielding from in-situ resources or
  products (Berms, bricks, plates water
  hydrocarbons)
• Shielding from micro-meteoroid and landing/ascent
  plume debris
• Habitat and equipment protection
• Roads, landing pads, site preparation, etc.

• Manufacturing w/ Space Resources
• Spare part manufacturing
• Locally integrated systems components
  (especially for increasing resource processing
  capabilities)
• High-mass, simple items (chairs, tables, chaises,
  etc.)

• Space Power Utilities
• Storage distribution of mission consumables
• Thermal energy storage use
• Solar energy (PV, concentrators, rectennas)
• Chemical energy (fuel cells, combustion,
  catalytic reactors, etc.)

28
Specific ISRU Examples from NASA Architectures

• Architecture mass reduction
• Mars Ascent Vehicle propellant production results
  in gt20 decrease in overall mission mass
• Dissimilar redundancy
• Oxygen production for life support
• Water caches for life support
• Energy caches (fuel cell reactants) for power
  production
• Simplification and increased reliability of
  systems
• Oxygen production allows Cryo PLSS / venting
  suit for EVA
• Elimination of entire flight elements
• Added functionality ( mass) possible for Mars
  Ascent Vehicle and elimination of Earth Entry
  Vehicle

29
ISRU Dependencies

• The use of space resources is
• Architecture dependant
• Long stay vs short stay (mission consumable mass
  increases with stay time)
• Pre-deploy vs all in one mission (pre-deploy
  allows longer production times but requires
  precision landing)
• Multiple mission to same destination vs single
  missions (multiple missions enables gradual
  infrastructure and production rate build up)
• High orbit vs low orbit rendezvous (increase in
  Delta-V increases benefit of in-situ produced
  propellant)
• Reuse vs single mission (reuse allows for single
  stage vs two stage landers)
• Customer dependant
• ISRU is only viable if use is designed into
  subsystems that utilize the products
  (propellants, radiation shielding, energy
  storage, surface equipment, spare parts, etc.)
• Time phased
• Early missions must require minimum
  infrastructure and provide the biggest mass/cost
  leverage (mission consumables have biggest
  impact)
• Surface construction and manufacturing will start
  with simple/high leverage products and expand to
  greater self-sufficiency capability
• ISRU is evolutionary and needs to build on
  lessons learned from previous work and show clear
  benefit metrics

30
Core ISRU Technologies Enable Multiple
Applications
Planetary Resource Utilization Maximizes
Benefits, Flexibility, Affordability
In-Situ Production Of Consumables for Propulsion,
Power, ECLSS
Life Support Systems for Habitats EVA
Core Technologies

• CO2 N2 Acquisition Separation
• Sabatier Reactor
• RWGS Reactor
• CO2 Electrolysis
• Methane Reforming
• H2O Separators
• H2O Electrolysis
• H2O Storage
• Heat Exchangers
• Liquid Vaporizers
• O2 Fuel Storage (0-g reduced-g)
• O2 Feed Transfer Lines
• O2/Fuel Couplings
• Fuel Cells
• O2/Fuel Igniters Thrusters

Water H2/O2 Based Propulsion
Fuel Cell Power for Spacecraft, Rovers EVA
Non-Toxic O2-Based Propulsion
0-g Reduced-g Propellant Transfer
31
Surface Infrastructure Based On Common
ISRU-Supplied Fluid
Life Support Systems for Habitats EVA
In-Situ Production Of Consumables
Habitat ECLSS
EVA ECLSS
Oxygen (O2)
Nitrogen (N2)
Production Rate Human Mars 2-4 kg of O2/hr
24 hr
Usage Rate 0.4 kg of O2/hr (crew 6)
Usage Rate 0.2 kg of O2/hr (crew 2)
Production, Storage Use of Common Fluids
Fuel Cell Power for Rovers EVA
Non-Toxic O2-Based Propulsion
Water (H2O)
Fuel (H2,CH4, etc.)
EVA Rover (600 W)
Human Ascent Propulsion
EVA Suit (50-100 W)
Usage Rate 0.5 kg of O2/hr
Human Rover (10 KW)
Usage Rate 9.4 kg of O2/hr
Usage Rate 20,000 kg O2
Usage Rate lt0.08 kg of O2/hr
JSC-Energy Systems Division
32
Mars ISRU Demonstration Rationale Approach

• Investigate Environment/Resources of interest
• Determining quantity and form of
  surface/sub-surface water is critical
• Maximum leverage if water is available on Mars
  (methane and oxygen)
• Significant leverage even if water not available
  (oxygen only)
• Location and acquisition of water remains the big
  unknown in ISRU planning
• Science missions will help determine locate
  possible recoverable water
• Marsis--gt SHARAD--gt Phoenix--gt MSL--gt other
  orbiter
• Demonstrate ISRU Hardware/Systems in relevant
  environment
• Mars environment interaction with ISRU plant
  cant be fully simulated on Earth
• Extended periods of test to simulate long
  duration flights will be difficult to perform
• Perform ISRU demonstrations in step-wise approach
  to increase confidence in environment/resource
  understanding and reduce mission application
  uncertainties
• Experiment development time, 26 month gaps in
  missions, trip times, and extended surface
  operations mean lessons learned from one mission
  can only influence missions 2 or 3 opportunities
  (4 or 6 years) later
• Parallel investigations of atmospheric and
  regolith/water-based processing with convergence
  before human mission
• Utilize step/spiral development of identified
  ISRU Capabilities
• Mission consumable production
• Water extraction processing

33
ISRU Challenges

• Maximize benefit of using resources, in the
  shortest amount of time, while minimizing crew
  involvement and Earth delivered infrastructure
• Early Mass, Cost, and/or Risk Reduction
  Benefits
• Processing and manufacturing techniques capable
  of producing 100s to 1000s their own mass of
  product in their useful lifetimes, with
  reasonable quality.
• Construction and erection techniques capable of
  producing complex structures from a variety of
  available materials.
• In-situ manufacture of spare parts and equipment
  with the minimum of required equipment and crew
  training
• Methods for energy efficient extracting oxygen
  and other consumables from lunar or Mars regolith
• Methods for mass, power, and volume efficient
  delivery and storage of hydrogen
• Long-duration, autonomous operation
• Autonomous control failure recovery (No crew
  for maintenance Non-continuous monitoring)
• Long-duration operation (ex. 500 days on Mars
  surface for propellant production)
• High reliability and minimum (zero) maintenance
• High reliability due to no (or minimal)
  maintenance capability for pre-deployed and
  robotic mission applications
• Networking/processing strategies (idle redundancy
  vs over-production/degraded performance)
• Development of highly reliable thermal/mechanical
  cycle units (valves, pumps, heat exchangers,
  etc.)
• Development of highly reliable, autonomous
  calibration control hardware (sensors,
  flowmeters, etc.)

34
ISRU Challenges (Cont.)

• Operation in severe environments
• Efficient excavation of resources in extremely
  cold (ex. Lunar permanent shadows),
  dusty/abrasive, and/or micro-g environments
  (Asteroids, comets, Mars moons, etc.)
• Methods to mitigate dust/filtration for Mars
  atmospheric processing
• Resource Unknowns
• Is water/ice, hydrogen, or both located in lunar
  polar and permanently shadowed crater? Is the
  ice/hydrogen accessible/useable?
• How much water is in the Mars regolith and can it
  be efficiently extracted? Is subterranean water
  present, what form is it in, and where?
• What are the material chemical and physical
  properties of Phobos NEO asteroids? How much
  water is available and in what form/concentration
  is it found (ice, hydrated clays, )?