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ESDMD #0803: Extravehicular Activity (EVA) and Intravehicular Activity (IVA) Suit System and Capabilities for Mars Missions

Spacesuits that work in Mars gravity and in the Martian atmosphere (bin 4, rating 31 of 57). The xEMU's heat rejection and CO2 removal depend on vacuum, and its mass is too great for a crew member to carry in Mars gravity. Mars suits will need different CO2 removal and thermal control than a lunar suit. A Mars-only gap, in the Humans to Mars segment (Tech gaps spreadsheet, ESDMD #0803).

Quotations below are from row ESDMD #0803 of the tech gaps spreadsheet. ADD Rev C's Appendix D prints the same table for this gap, and it matches the row field for field (ADD Rev C, p. 238).

Description

"Many new roles for humans performing EVAs, upgrades in EVA suits, and tools are an essential part of achieving mission success. While there are multiple options for Mars, human missions may require radical changes in the approach to EVA suit design and mass to ensure crew can operate effectively in the Mars gravity and atmosphere. Furthermore, there is unknown material degradation due to radiation beyond LEO that future suits must account for."

Impacts and benefits: "Without gap closure, Mars EVA will not be possible without new suits. Furthermore, the high EVA system mass will limit crew's abilities on Mars surface and could further exacerbate crew injury risk. Degraded performance will limit EVA time or restrict crew activity, increase system mass, and/or increase logistics transfer, etc. In addition, science objectives will not be met without adequate tool availability."

Current state of the art

"The xEMU heat rejection and CO2 removal systems are dependent on operating in a vacuum environment as opposed to the Martian atmosphere. The xEMU system mass is also incompatible with a Mars surface gravity environment due to the too-large workload for the astronaut."

Performance target

Mars: "Mars spacesuits must be compatible with the surface gravity environment and the presence of an atmosphere. Mars spacesuits will require a different CO2 removal technology and thermal management technology than a lunar surface suit. Further, Mars spacesuits must be capable of supporting TBD concepts of operation with respect to EVA dwell time, EVA frequency, and use life."

Child gaps

  • 0803-01: Continuous CO2 removal systems for Mars surface EVA suit in Martian atmosphere
  • 0803-02: Thermal control systems for Mars surface EVA suit in non-vacuum
  • 0803-03: Mars surface EVA suit dust mitigation tools and systems
  • 0803-04: Earth-independent maintenance, reuse, and repair of Mars surface EVA suit

For the Moon, EVA suit dust mitigation is a child of the lunar dust gap (0801-03 under #0801). For Mars it sits here (0803-03), not under the Mars dust gap #0802.

Traceability

  • Use cases and functions: UC-M-101 M -- All FN
  • Definition tasks: Mars: MD-10 Mars Forward Contamination Planetary Protection Risk Posture; Crew Surface Mobility Strategy; Surface EVA Capability Strategy; Exploration EVA Schema

Segments and sub-architectures

Priority

Priority bin 4, overall prioritization rating 31 of 57. It is the first gap in bin 4. The rating is "the gap's location in the prioritized list of gaps", so 1 is the highest priority, and bins group gaps of similar priority, bin 1 highest. Criticality, urgency, breadth and depth set the order; cost is not considered (ADD Rev C, pp. 78, 199; method on the gaps index).

Moon Base relevance

Not established by the sources so far. The gap is Mars-only in the spreadsheet, and the Users Guide does not name it among its near-term Moon Base challenges (Technology and knowledge challenges). The Users Guide's Mars-forward discussion is on Mars-forward.

Sources

Tech gaps spreadsheet, ESDMD #0803 · Planetary protection white paper, p. 4 · ADD Rev C, pp. 48, 78, 199, 238 · Ignition deck 1, slide 18