Soteria:�Salvation Delivered from Lunar Orbit

James Robertson

Engineer Degree Candidate

jamesrob@usc.edu

Astronautical Engineering Department

December 14, 2021

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Context: Near-Term Lunar Exploration

Rescue is a critical element

• Obligated under Outer Space Treaty & Rescue Agreement
• Artemis Accords affirm importance of rendering assistance: “Signatories commit to taking all reasonable efforts to render necessary assistance to personnel in outer space who are in distress” [1]

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Initial Artemis landings

Advanced exploration

Commercial missions, tourism

[2], [3], [4]

Space Rescue Past and Future

Artemis

architecture does not articulate a rescue plan: abort is only option

aborts can take up to 3.5 days(!) from surface to the Gateway in NRHO [11]

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Gemini Lunar Survival Shelter

LEAP Lunar Flyer

Lunar Escape System

Skylab Rescue CM

Shuttle rescue on stand-by for Hubble mission

Rescue Ball

Operation Hermes (USC MAXIM 2019)

proposed a second lander to retrieve crew in an emergency

[12]

[5], [6], [7], [8], [9], [10]

Concept Introduction: Emergency Services

Emergency aid supplies stored in Low Lunar Orbit (LLO)

Small, CLPS derived lander transports supplies and lands near surface crew

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O₂

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F

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Long Tail of Emergencies

Each type of emergency is low-probability, but the long-tail of them all together can be a significant risk

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Medical emergency

Low on oxygen

Life support breakdown

Water shortage

Spoiled food

Broken space suit

Rover breakdown

Habitat failure

Solar flare

etc

Medical supplies

Emergency oxygen

Life support equipment parts

Water

Food

Space suit

Rover parts

Emergency shelter

Shielded shelter

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O₂

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Orbital Segment

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Lander

Hangar

Prepackaged supplies

Automated loading and dispatch of prepackaged supplies

Multiple landers available to be dispatched for one or more emergencies

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Micrometeoroid

and thermal

protection

Lunar Gateway

Lander Based on CLPS Vehicles

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Many options in development

[13], [14], [15], [16], [17]

Orbital Coverage

• Assumes Gateway in LLO instead of NRHO
• Orion would need refueling for a round-trip mission
• Gateway orbit adjusted to track over the crew(s) on the surface
• Flight time (1 – 3 hrs) driven by descent (1 hr) + orbital period (2 hrs)

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[18]

Orbital Coverage

• Assumes Gateway in LLO instead of NRHO
• Orion would need refueling for a round-trip mission
• Gateway orbit adjusted to track over the crew(s) on the surface
• Flight time (1 – 3 hrs) driven by descent (1 hr) + orbital period (2 hrs)
• 500 km of cross range possible with <300 m/s plane change

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[18]

Cislunar Rescue Coverage

CLPS-class vehicles in LLO capable of reaching throughout cislunar space – down to GEO

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(map not to scale)

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GEO

[19]

L4

L5

L1

L2

L3

Example Payload: InstaShelter

Inflatable shelter provides backup to primary habitat

Minimum size – large enough for crew to remove space suits

Minimal consumables

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1965 Goodyear Inflatable Concept

Inflatable cabin

Pressurized ribs

Hatch

Shirtsleeve

environment

[20]

Example Payload: Solar Storm Protection

Rover gathers upper centimeter of loose regolith and ejects it in an arc, depositing it onto the shelter

Steered using remote control

Alternatively, could inflate InstaShelter underneath massive object: crewed lander, rover, boulder

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Buried InstaShelter

Ingester

Regolith spray

Rover

Single Crew Evacuation

Small ascent vehicle to evacuate single crewmember from surface expedition

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Pressurized cabin

Griffin-class propulsion

Roll-on stretcher

Standard docking hatch

Expedition rover

[21]

Merits & Limitations

More affordable Human Exploration:

• Lower logistics burden: crewed expedition can be smaller and lighter = fewer launches
• Faster: lighter expedition can travel quicker, more aggressive exploration
• Safer: larger variety of emergency supplies can be provided
• Co-operative: one set of emergency supplies can be on standby for multiple exploration crews = fewer launches

Limitations:

• CLPS limits size of payloads (although multiple landers can be dispatched)
• Flight time of 1 – 3 hours (could be reduced with multiple orbital segments)
• Need to refuel Orion for round-trip to LLO
• More complex system compared to carrying emergency supplies with crew

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Future Work

• Define possible emergency supply packages
• Analyze mission performance based on CLPS lander
• Conceptual design of landers
• Operations Analysis and optimization of system
• Explore ideas for emergency supplies dispatched via hopper from lunar surface base

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References

1. Space Policy Directive 1 https://history.nasa.gov/presmemo12-11-17.pdf
2. Artemis Plan https://www.nasa.gov/sites/default/files/atoms/files/artemis_plan-20200921.pdf
3. SpaceX HLS https://www.nasa.gov/press-release/as-artemis-moves-forward-nasa-picks-spacex-to-land-next-americans-on-moon/
4. Artemis https://www.nasa.gov/specials/artemis/
5. Gemini Lunar Survival Shelter http://astronautix.com/g/geminilunarrvivalshelter.html
6. Lunar Escape System https://en.wikipedia.org/wiki/Lunar_escape_systems
7. LEAP Lunar Flyer http://www.astronautix.com/l/leaplunarflyer.html
8. Skylab Rescue CM https://en.wikipedia.org/wiki/Skylab_Rescue
9. Shuttle Rescue Ball http://www.astronautix.com/r/rescueball.html
10. Space Shuttle https://en.wikipedia.org/wiki/STS-3xx#/media/File:Space_shuttles_Atlantis_(STS-125)_and_Endeavour_(STS-400)_on_launch_pads.jpg
11. Whitley, R., Martinez, R. Options for Staging Orbits in Cis-Lunar Space https://ntrs.nasa.gov/api/citations/20150019648/downloads/20150019648.pdf
12. Operation Hermes https://drive.google.com/file/d/1lcCKcMRknEXv2ZMw7eFVMD-5fcDO82Z9/view?usp=drive_web
13. Intuitive Machines Nova-C https://en.wikipedia.org/wiki/Nova-C
14. Astrobotic Peregrine https://en.wikipedia.org/wiki/Astrobotic_Technology#Peregrine_lander
15. Masten XL-1 https://en.wikipedia.org/wiki/Masten_Space_Systems#XL-1
16. Masten XL-1 https://masten.aero/lunar-vehicles/
17. Firefly Blue Ghost https://firefly.com/lunar-lander/
18. Astrobotic Griffin https://www.astrobotic.com/lunar-delivery/landers/griffin-lander/
19. Lunar surface https://moon.nasa.gov/resources/119/lunar-surface-in-color/
20. Goodyear Stay Time Extension Module https://ntrs.nasa.gov/api/citations/19710028062/downloads/19710028062.pdf
21. South Pole Rescue https://www.npr.org/sections/thetwo-way/2016/06/22/483121098/risky-south-pole-rescue-succeeds-as-2-patients-are-airlifted-out

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Backup

Crews on Lunar Surface Will Need Shelter from Solar Flares

• Consequences of large solar flare are very high: powerful flares could incapacitate astronauts, and could kill without adequate medical care
• Potentially arriving with little or no warning
• NASA’s 30-day dose limit for bone marrow: 25 cGy-eq
• 1972 Solar Particle Event (SPE): one of the largest and shortest, <1 day
• 1972 SPE estimated to cause a total dose of 64 cGy-eq behind 5 g/cm^2 of aluminum (typical of spacecraft)
• Behind 50 g/cm^2 of aluminum (0.33 meters of regolith) reduces total dose to <1 cGy-eq

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Even with no warning, in first hour of 1972 SPE, astronaut in spacesuit accumulates <1 cGy

Gemini Lunar Surface Survival Shelter

• 1967 Proposal for helping stranded Apollo astronauts
• “In the event the LM ascent stage would not light to take the crew back to the Apollo CSM in lunar orbit, the two astronauts could go to the shelter and await a rescue mission.”

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http://astronautix.com/g/geminilunarrvivalshelter.html

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LEAP Lunar Flyer

• 1961 Concept for ambulance to return disabled astronaut to lunar orbit
• “The disabled crew member would be laid horizontally in a cylindrical pressurized capsule. At the necessary moment before the rescue craft passed overhead, the engine on the litter would ignite…”

http://www.astronautix.com/l/leaplunarflyer.html

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Lunar Escape System

• 1970 Study for a way for stranded Apollo astronauts to escape from the lunar surface
• Uses fuel from Apollo LM ascent stage

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https://web.archive.org/web/20061129003517/https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19700022470_1970022470.pdf

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Lunar Surface Emergency Shelter

• 1993 Study into solar flare survival options for astronauts on lunar surface
• Good information on radiation
• Design 2 - Rigid cylinder uses regolith for shielding

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NASA-CR-195551

https://ia801002.us.archive.org/8/items/swus-lunarplanetaryscience/Surface%20Operations%20Volume%20I_%20%20Lunar%20Surface%20Emergency.pdf

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Lunar Storm Shelter

• 1988 Concept for radiation storm shelter on the moon
• Good information on radiation
• Options for buried and minimum size shelters

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https://ntrs.nasa.gov/api/citations/19890003770/downloads/19890003770.pdf

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Stay Time Extension Module

• 1965 Goodyear proposal for inflatable lunar shelter to extended astronaut time on lunar surface

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NASA NTRS report N67-33706

https://ntrs.nasa.gov/api/citations/19710028062/downloads/19710028062.pdf

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Inflatable Habitation for the Lunar Base

• 1988 Concept for inflatable lunar habitat, using “sandbags” of regolith for radiation protection

The Second Conference on Lunar Bases and Space Activities of the 21st Century, Proceedings from a conference held in Houston, TX, April 5-7, 1988. Edited by W. W. Mendell, NASA Conference Publication 3166, 1992., p.249

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