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ESDMD #0401: Crew Exercise Countermeasures to Support Extended Habitation in Space

Smaller, lighter exercise equipment and assessment tools that keep crews fit for surface EVA after long periods in deep space (bin 5, rating 40 of 57). ISS exercise systems work for microgravity but are "mass-, power-, and volume-intensive" and not fully effective for egress or "immediate surface EVA after a long period in deep space". Targets are 365 days in space for the Moon and 2–3 years for Mars (Tech gaps spreadsheet, ESDMD #0401).

Quotations below are from row ESDMD #0401 of the tech gaps spreadsheet unless marked otherwise. 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. 218).

Description

"ISS crew rely on exercise countermeasures to mitigate health effects associated with long-duration exposure to microgravity. However, current systems are mass-, power-, and volume-intensive and are sufficient for microgravity extravehicular activities (EVA) but not completely effective for crew egress or immediate surface EVA after a long period in deep space. Mass efficient and effective exercise is needed for preventing injury and providing muscle/cardio fitness in preparation for crew activities, including surface EVA. For long-duration missions, effective exploration-compatible exercise countermeasures and assessment tools are needed for crew to accurately maintain and monitor physical health and performance during exploration missions."

Impacts and benefits: "Without gap closure, the impacts are large mass/volume exercise equipment and/or potential crew health decrements from inadequate countermeasures. Use of current systems may be incompatible with future vehicles. Potential impacts to spares and maintenance. (TBR)"

Current state of the art

"ISS exercise countermeasures address aerobic, muscle, and bone loss risk. Ongoing work on exploration solutions (TBR). Currently, ground support provides exercise data interpretation. Use of multiple on-orbit devices and the efficacy to support high-frequency lunar and Martian surface EVA unassisted is still being researched. As we move to exploration missions, the communication delay will introduce new issues, and will force crew to be more self-reliant."

Performance target

  • Moon/Mars: "Hardware and software that 1) are sufficient to meet crew health and performance standards for aerobic fitness, muscle strength, bone health for extraterrestrial surface injury risk minimization; 2) require planned maintenance of no more than (TBD); and 3) are applicable for in-transit and surface mission phases."
  • Moon: "In addition, support mission durations up to 365 days in space."
  • Mars: "In addition, hardware and software that are compatible with Mars mission, systems, and operations. Support mission durations on the order of 2-3 years."

Child gaps

  • 0401-01: Crew health and performance countermeasure modeling
  • 0401-02: Exercise countermeasures for microgravity and reduced-gravity environments
  • 0401-03: Bone countermeasures for long-duration exploration missions
  • 0401-04: Cardiovascular countermeasures for microgravity and reduced-gravity environments

Traceability

  • Use cases and functions: UC-X-103 L -- FN-X-103 L; UC-X-104 L -- FN-X-104 L; UC-X-101 M -- FN-X-101 M; UC-X-102 M -- FN-X-102 M. The four crew countermeasure gaps (#0401–#0404) list exactly these four pairs.
  • Against the Mars decomposition: the Mars spreadsheet doesn't make either Mars pair. It puts FN-X-101 M under UC-H-102 M, UC-H-104 M, UC-X-105 M and UC-X-107 M, and FN-X-102 M under UC-H-103 M, UC-H-105 M, UC-X-106 M and UC-X-108 M. UC-X-101 M and UC-X-102 M (medical care and emergency response) have emergency functions instead (FN-H-123 M to FN-H-126 M, FN-X-109 M to FN-X-112 M, FN-L-301 M, FN-L-302 M). The pairs are kept as the gap prints them (Mars use cases; open question 60).
  • Definition tasks: Mars: MD-09 Maximum Mars Crew Surface Stay Duration; Maximum Total Crew Mission Duration
  • Cross-reference: FN-X-103 L, "Provide crew countermeasure system(s) to support the crew for moderate durations (month+) on the lunar surface", is also one of the Users Guide's Phase 1 functional gaps (Users Guide, p. 9; see Phase 1 functional gaps). This link joins the two sources; neither makes it. UC-X-103 L -- FN-X-103 L also appears under #0402, #0403, #0404 and #0405.

Segments and sub-architectures

Priority

Priority bin 5, overall prioritization rating 40 of 57. 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 Users Guide does not name #0401 among its near-term Moon Base challenges (Technology and knowledge challenges). Two passages touch the same subject without citing this gap:

  • A Phase 1 habitation capability target: "Demonstrate extended crew habitation capabilities, including hygiene, exercise, and nutrition" (Users Guide, p. 9; see Phase 1 functional gaps).
  • The Mars-forward area "Human factors": the Moon Base will "help mission designers better plan for prolonged missions, gravity adaptations, and partial gravity EVAs" (Users Guide, p. 14; see Mars-forward).

Sources

Tech gaps spreadsheet, ESDMD #0401 · ADD Rev C, pp. 78, 199, 218 · Users Guide, pp. 9, 14