Extending NASAs Exploration Systems Architecture towards Longterm Crewed Moon and Mars Operations

1
Extending NASAs Exploration Systems Architecture
towards Long-term Crewed Moon and Mars Operations

• Wilfried Hofstetter
• Paul Wooster
• Edward Crawley
• June 21, 2006
• AIAA Space Operations 2006 Conference
• Rome, Italy

2
Outline

• Introduction
• Exploration Requirements Analysis
• Lunar Mission Extension Options
• Mars Mission Extension Options
• Conclusions and Recommendations

3
Introduction

• NASAs Exploration System Architecture Study
  (ESAS) provided conceptual design of vehicles to
  enable a return to the Moon
• Crew Exploration Vehicle (CEV) for crew
  habitation during earth launch and entry and
  transit to and from the Moon, as well as
  trans-earth injection propulsion from the Moon
• Crew Launch Vehicle (CLV) to launch the CEV into
  Earth orbit
• Lunar Surface Access Module (LSAM) to capture the
  CEV and LSAM into lunar orbit, transport crew in
  between the lunar surface and lunar orbit, and
  support the crew on the lunar surface for up to 7
  days
• Cargo Launch Vehicle (CaLV) and Earth Departure
  Stage (EDS) for launching the LSAM into Earth
  orbit and propelling the LSAM and CEV towards the
  Moon
• The ESAS design focus was on providing capability
  for initial sorties on the lunar surface
• This paper investigates options to extend the
  ESAS elements towards longer duration lunar
  missions as well as Mars missions

4
Lunar Architecture Extension Analysis
Lunar crew transportation architecture extension
ideas from the Apollo program
Apollo Lunar Shelter / Rover, 1964
Apollo LM-derived rover (MOLEM), 1966
Apollo LM shelter and habitat, 1966
Apollo CM-derived rover (MOCOM), 1966

• Motivation for the analysis
• Reduction of life-cycle cost and development time
  for extended human lunar and Mars exploration
• Process
• Identification of options for extending the
  capabilities of the lunar crew transportation
  system towards longer lunar surface stays and
  outpost missions with minimal additional
  development cost
• Derivation of recommendations for hooks and scars
  to be considered in human lander design in order
  to facilitate / enable extension options
• Analysis based on ESAS design because it was the
  only one available at the time

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Lunar Extended Sortie
Extended sortie configuration
Hadley Apennine extended sortie mission
25 km radius
Solar arraydeployedon the surface
17 km radius
13 km radius
Lander
Examplelanding site
x
Powercables
x
Apollo 15
Solar arraydeployedon the surface
Surface mobility

• Extended sortie uses human lunar lander with
  extended life-support consumables and solar
  arrays for surface power generation
• Surface mobility analysis suggests that
  unpressurized mobility can provide up to 25 km of
  range from landing site if limited SPE prediction
  capability is available (minimum of 13 km)
• Anytime abort constraint dictates polar or
  equatorial landing site for missions longer than
  7 days (CEV plane change capability limit)

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Lunar Extended Sortie Polar Site
Cargo mass increase couldbe realized by
delta-vsavings compared to globalaccess sortie
missions
Solar arrays (red lines) mostlikely
configuration for extended sortie

• Different colors represent different
  configurations
• Black regular human lander using fuel cells for
  power generation
• Red regular lander solar arrays
• Blue regular lander solar arrays wash water
  regeneration
• Green regular lander solar arrays wash water
  regeneration regenerative CO2 removal
• Different contours represent different average
  power levels (5, 10, 15, 20 kW)

7
Lunar Extended Sortie Equatorial Site
Cargo mass increase couldbe realized by
delta-vsavings compared to globalaccess sortie
missions
Solar arrays (red lines) mostlikely
configuration for extended sortie

• Different colors represent different
  configurations
• Black regular human lander using fuel cells for
  power generation
• Red regular lander solar arrays
• Blue regular lander solar arrays wash water
  regeneration
• Green regular lander solar arrays wash water
  regeneration regenerative CO2 removal
• Different contours represent different average
  power levels (5, 10, 15, 20 kW)

8
Lunar Intermediate Outpost
LSAM-derived outpost,habitat for 2 crew
Visiting LSAM, serves assecond habitat for 2 crew
LSAM descent stagefrom previous visit
Safe distance (blast effects)
Safe distance (blast effects)
Powercable
Visiting LSAM
Solar arraydeployedon the surface
Surface mobility

• Intermediate outpost mission is intended to
  provide initial long-duration mission capability
  (Skylab on the Moon)
• Designed to be visited several times (visiting
  lander serves as second pressurized volume)
• Requires 1 HLLV pre-deployment flight to deliver
  a modified human lander (no ascent propulsion)
• Polar or equatorial landing site required due to
  anytime abort constraint
• Unpressurized surface mobility provides
  sufficient range for exploration
• Intermediate outpost could potentially be
  extended into a long-term outpost
• Provision of additional pressurized volume so
  that crew does not have to split up into two
  teams for habitation

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Lunar Intermediate Outpost Polar Site (1)
Cargo mass deliveredwith pre-deployment flight
Solar arrays and regenerative lifesupport (blue
/ green lines) mostdesirable configuration for
extended sortie

• Different colors represent different
  configurations
• Black regular human lander using fuel cells for
  power generation
• Red regular lander solar arrays
• Blue regular lander solar arrays wash water
  regeneration
• Green regular lander solar arrays wash water
  regeneration regenerative CO2 removal
• Different contours represent different average
  power levels (5, 10, 15, 20 kW)

10
Lunar Intermediate Outpost Equatorial Site
Cargo mass deliveredwith pre-deployment flight
Solar arrays and regenerative lifesupport (blue
/ green lines) mostdesirable configuration for
extended sortie

• Different colors represent different
  configurations
• Black regular human lander using fuel cells for
  power generation
• Red regular lander solar arrays
• Blue regular lander solar arrays wash water
  regeneration
• Green regular lander solar arrays wash water
  regeneration regenerative CO2 removal
• Different contours represent different average
  power levels (5, 10, 15, 20 kW)

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Mars Exploration Elements

• Following list of elements required for Mars
  exploration
• Earth Launch and Entry Crew Cabin(s)
• Heavy Lift Launch Vehicle and Earth Departure
  Systems
• Descent Stage
• Heatshields
• Long-term Surface Habitat
• Mars Ascent Vehicle (Cabin and Propulsion)
• Earth Return Vehicle (Habitat and Propulsion)
• EVA and Mobility Systems
• Surface Power Systems
• Following list of technologies beneficial for
  Mars missions
• In-Situ Propellant Production/In-Situ Consumables
  Production
• Methane-Oxygen Propulsion

Items denoted in blue indicate high potential for
Moon-Mars commonality
12
ESAS Launch Vehicle Mars Capability (no
modifications, uses existing H2/O2 propulsion)
TMI Trans-Mars Injection MO Mars Orbit MS
Mars Surface
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Conceptual Mars Exploration Architecture Based on
Lunar Elements
Mars Surface
Mars Orbit
Interplanetary Transfer
Earth Vicinity
Mars Crew Transportation System Concept
Trans-Mars Configuration
Launch Configuration
Logistics Flights
Surface Habitat
Crew Transport
14
Conceptual Mars Exploration Architecture Based on
Lunar Elements
Mars Surface
Mars Orbit
Interplanetary Transfer
Earth Vicinity
Logistics Flights
Surface Habitat
Crew Transport
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Summary and Conclusions

• Two major types of lunar extension missions
• Extension of sorties using photovoltaic power
  generation and additional consumables (several
  weeks at the pole and equator)
• Intermediate outpost missions using a
  pre-deployment flight of a modified human lander
  (no main ascent propulsion) and additional
  consumables (up to 300 days at the pole, 90 days
  at the equator for one pre-deployment flight)
• Only limited re-development required to enable
  lunar extension missions (technologies and
  hardware available today)
• Addition of solar arrays for surface power
  generation
• Potentially wash water regeneration
• Initial analysis indicates options exist to
  extend ESAS elements towards Mars missions
• CaLV provides significant trans-Mars injection
  capability, even without nuclear thermal rockets
  or other advanced propulsion options
• Further work planned to define how HuLL elements
  can be extended and determine any hooks and
  scars on lunar elements to ease the transition
  will be conducted
• Photovoltaic power generation option for extended
  lunar missions
• Interfaces for lander regenerative life support
  (wash water, CO2 removal)

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Aeroshell Sizing Impact on Delivered Mass

• CER aerocapture and aeroentry analysis indicated
  that aeroshell sizing (diameter) would have a
  major impact on maximum mass of Mars systems
• ESAS CaLV has a fairing diameter of 8.4 meters,
  although larger fairings for Mars systems would
  likely be possible
• For equal ballistic coefficient, the following
  entry mass limits likely apply for entry systems
  of the specified diameter

Georgia Tech CER Aeroentry Analysis (Ventry
4.63 km/s, L/D 0.5)
8.42 71
102 100
122 144
152 255
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Moon-Mars Launch Manifest

• Mars requires up to 6 launches in approximately 3
  months
• Launch windows for most restrictive
  opportunities
• Cargo Launch Window 22-Jun-22 -gt 19-Aug-22
• Crew Launch Date 8-Sep-22
• Cargo Launch Window 5-Jan-33 -gt 2-Mar-33
• Crew Launch Date 13-Apr-33
• It may be possible to continue lunar missions
  during interludes in Mars launch operations, as
  shown below
• Single launch lunar missions would help with this

27 months
6 months
6 months
6 months
6 months
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Motivation and Previous Studies
Apollo Lunar Shelter / Rover, 1964
Apollo LM-derived rover (MOLEM), 1966
Apollo LM shelter and habitat, 1966
Apollo CM-derived rover (MOCOM), 1966
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Yes
No
Initial lunar sorties
Lunar outpost
Yes
No
Yes
Sorties duringlunar outpost phase
Yes
No
No
N/A
Outpostlocation
Equatorial
70-80 deg.
N/A
Polar
Equatorial
70-80 deg.
Polar
Equatorial
70-80 deg.
Polar
Marsmissions?
Y
N
Y
Y
Y
N
N
N
N
Y
Y
Y
Y
N
N
Y
N
N
Y
N
N/A
N/A
N/A
N/A
N/A
N/A
Lunar activitiesduring Marsexploration(if
applicable)
N/A
N/A
N/A
N/A
None
None
None
None
None
Outpost
Sorties
Sorties
Sorties
Sorties
None
None
None
None
Outpost
None
Outpost
Outpost
Outpost
Outpost
Outpost
Outpost
OS
Outpost
OS
OS
None Lunar sorties Lunar outpost Outpost
sorties