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ESDMD #1104: Mars Transportation Propulsion

Propulsion able to move large, human-class systems between Earth and Mars (bin 1, rating 6 of 57). The trade space is open: nuclear thermal, nuclear electric, chemical, solar electric and hybrid systems are all candidates, and the choice depends on definition tasks such as crew and cargo propulsion type. A Mars-only gap, in the Humans to Mars segment (Tech gaps spreadsheet, ESDMD #1104).

Quotations below are from row ESDMD #1104 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. 255).

Description

"To support crewed missions to Mars, there is a need for propulsion systems capable of transporting large, human-class systems to Mars vicinity. There are several technology options being considered for the Mars transportation propulsion system. Nuclear systems, non-nuclear systems, high-thrust ballistic systems, low-thrust systems, and hybrid high-/low-thrust systems are just a few of the options currently in the propulsion technology trade space. The trade space will be informed by multiple definition tasks, including total mission duration, transit habitation strategy, mission mode operation, and others."

Impacts and benefits: "Without gap closure, propulsion system trade space may become constrained to few options, substantially increasing cost of Mars missions or threatening viability."

Current state of the art

"Chemical combustion solutions are current state of the art, but aggregation of chemical propellant has not been demonstrated on orbit. NTP and NEP are at low TRL at human exploration scale. SEP for Gateway is at TRL 6. All of the above may need a larger-scale propulsion system for Mars than has been tested/built."

Performance target

Mars: "Enable the transfer of crew and cargo between Earth and Mars. Desired propulsion system performance will be informed by ongoing and future definition tasks."

Child gaps

  • 1104-01: Nuclear thermal propulsion (NTP) for Mars transportation
  • 1104-02: Nuclear electric propulsion (NEP) for Mars transportation
  • 1104-03: Main stage chemical propulsion systems for Mars transportation
  • 1104-04: Solar electric propulsion (SEP) systems for in-space Mars transportation
  • 1104-05: Dynamic power conversion and management systems for exploration-class electric propulsion systems
  • 1104-06*: In-space transfer of electric propulsion (EP) propellant
  • 1107-04*: Hardware components for repeated reuse for low-loss cryogenic fluid transfer in space

The starred child gaps also appear under #0503 (1104-06) and #1107 (1107-04). The asterisk marks "a child gap with multiple parents" (ADD Rev C, p. 199).

Traceability

  • Use cases and functions: UC-T-105 M -- All FN; UC-T-108 M -- All FN; UC-T-203 M -- All FN
  • Definition tasks: Mars: Crew In-Space Propulsion Type; Cargo In-Space Propulsion Type; In-Space Transportation Systems Reuse Strategy; Crew Mars Parking Orbit

Segments and sub-architectures

Priority

Priority bin 1, overall prioritization rating 6 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 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 #1104 · ADD Rev C, pp. 78, 199, 255 · Ignition deck 5, slides 11–12