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Extending NASA’s Exploration Systems Architecture towards Long-term Crewed Moon and Mars Operations: 

Extending NASA’s 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

Outline: 

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

Introduction: 

Introduction NASA’s 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

Lunar Architecture Extension Analysis: 

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

Lunar Extended Sortie: 

Lunar Extended Sortie 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) x Apollo 15 x Hadley – Apennine extended sortie mission Example landing site 25 km radius 17 km radius 13 km radius Extended sortie configuration Lander Solar array deployed on the surface Solar array deployed on the surface Power cables Surface mobility

Lunar Extended Sortie: Polar Site: 

Lunar Extended Sortie: Polar Site 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) Cargo mass increase could be realized by delta-v savings compared to global access sortie missions Solar arrays (red lines) most likely configuration for extended sortie

Lunar Extended Sortie: Equatorial Site: 

Lunar Extended Sortie: Equatorial Site 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) Cargo mass increase could be realized by delta-v savings compared to global access sortie missions Solar arrays (red lines) most likely configuration for extended sortie

Lunar Intermediate Outpost: 

Lunar Intermediate Outpost 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 Visiting LSAM, serves as second habitat for 2 crew LSAM-derived outpost, habitat for 2 crew LSAM descent stage from previous visit Safe distance (blast effects) Safe distance (blast effects) Visiting LSAM Solar array deployed on the surface Power cable Surface mobility

Lunar Intermediate Outpost: Polar Site (1): 

Lunar Intermediate Outpost: Polar Site (1) 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) Cargo mass delivered with pre-deployment flight Solar arrays and regenerative life support (blue / green lines) most desirable configuration for extended sortie

Lunar Intermediate Outpost: Equatorial Site: 

Lunar Intermediate Outpost: Equatorial Site 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) Cargo mass delivered with pre-deployment flight Solar arrays and regenerative life support (blue / green lines) most desirable configuration for extended sortie

Mars Exploration Elements: 

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

ESAS Launch Vehicle Mars Capability (no modifications, uses existing H2/O2 propulsion): 

ESAS Launch Vehicle Mars Capability (no modifications, uses existing H2/O2 propulsion) TMI – Trans-Mars Injection; MO – Mars Orbit; MS – Mars Surface

Conceptual Mars Exploration Architecture Based on Lunar Elements: 

Mars Crew Transportation System Concept Launch Configuration Trans-Mars Configuration Logistics Flights Surface Habitat Crew Transport Mars Orbit Interplanetary Transfer Earth Vicinity Mars Surface Conceptual Mars Exploration Architecture Based on Lunar Elements

Conceptual Mars Exploration Architecture Based on Lunar Elements: 

Logistics Flights Surface Habitat Crew Transport Conceptual Mars Exploration Architecture Based on Lunar Elements Mars Orbit Interplanetary Transfer Earth Vicinity Mars Surface

Summary and Conclusions: 

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)

Aeroshell Sizing Impact on Delivered Mass: 

Georgia Tech CE&R Aeroentry Analysis (Ventry = 4.63 km/s, L/D = 0.5) Aeroshell Sizing Impact on Delivered Mass CE&R 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: 8.4^2 = 71 10^2 = 100 12^2 = 144 15^2 = 255

Moon-Mars Launch Manifest: 

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 -> 19-Aug-22 Crew Launch Date: 8-Sep-22 Cargo Launch Window: 5-Jan-33 -> 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 6 months 6 months 6 months 6 months 27 months

Motivation and Previous Studies: 

Apollo Lunar Shelter / Rover, 1964 Apollo LM-derived rover (MOLEM), 1966 Apollo CM-derived rover (MOCOM), 1966 Apollo LM shelter and habitat, 1966 Motivation and Previous Studies

Slide20: 

Lunar outpost Yes Initial lunar sorties No No Yes Yes Sorties during lunar outpost phase No Yes N/A No Outpost location Equatorial Polar 70-80 deg. Equatorial Polar 70-80 deg. N/A Equatorial Polar 70-80 deg. Mars missions? N Y N Y N Y N Y N Y N Y N Y N Y N Y N Y Lunar activities during Mars exploration (if applicable) None Lunar sorties Lunar outpost Outpost + sorties Sorties Outpost O+S None N/A Sorties Outpost O+S None N/A Sorties O+S None N/A Outpost None N/A Outpost None N/A Outpost None N/A Outpost None N/A Sorties None N/A Outpost None N/A Outpost None N/A Outpost