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ESDMD #1106: Cryogenic Fluid Storage

Storing cryogenic fluids such as propellants for long durations with little boil-off or leakage, and gauging how much is left in a tank at any time (bin 4, rating 32 of 57). Today's boil-off rates force a propellant mass margin of 15–20%. A zero boil-off tank experiment series has flown on ISS (Tech gaps spreadsheet, ESDMD #1106). Its sister gap, cryogenic fluid transfer (#1107), is rated 4.

Quotations below are from row ESDMD #1106 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. 257).

Description

"There is a need to store certain fluids, such as propellants for propulsion assets, at cryogenic temperatures during long-duration missions and to quantify the amount of propellant remaining within a tank at any time. This capability would enable long-duration missions with minimal loss of cryogenic fluids and reduce the need for additional elements carrying propellant that compensates for loss to boil-off, leakage, and uncertainties of usage. Additionally, propellant gauging will be critical to determine the remaining propellant and track any additional losses that occur from boil-off, leakage, or inefficiencies from venting and pressurization."

Impacts and benefits: "Closing this gap enables long-duration missions using cryogenic propellant systems with minimal unintended propellant losses and the ability to quantify remaining propellant in tank."

Current state of the art

"Boil-off rate in current storage solutions necessitates additional propellant mass margin of 15%-20%. A zero boil-off tank experiment series has been conducted aboard ISS."

Performance target

  • Moon/Mars: "System that can efficiently store propellant for long-durations in microgravity and partial gravity environments while minimizing boil-off."
  • Mars: "In addition, increased autonomy and reliability compared to the lunar performance target."

Child gaps

  • 1106-01: Thermal management for long-duration cryogenic fluid storage
  • 1106-02: Fluid management for long-duration cryogenic fluid storage
  • 1106-03*: High-efficiency cryo-coolers at 20K and 90K temperature class

The starred child gap also appears under #1201, sample storage. The asterisk marks "a child gap with multiple parents" (ADD Rev C, p. 199).

Traceability

  • Use cases and functions: UC-U-503 L -- FN-U-504 L; UC-U-504 L -- FN-U-503 L; UC-I-102 L -- FN-I-105 L; UC-T-108 M -- FN-T-211 M; UC-T-108 M -- FN-T-212 M; UC-U-501 M -- FN-U-504 M; UC-I-102 M -- FN-I-104 M
  • Definition tasks: Mars: Crew In-Space Return Propellant Strategy; Crew Mars Ascent Propellant Strategy; Crew In-Space Propulsion Type; Cargo In-Space Propulsion Type

Use case UC-I-102 L also appears under #0601 (oxygen extraction, "All FN") and #1107. The sheet does not name the use cases; ADD Rev C's titles for them are on Lunar use cases and Mars use cases.

Segments and sub-architectures

Priority

Priority bin 4, overall prioritization rating 32 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 #1106 among its near-term Moon Base challenges (Technology and knowledge challenges).

Sources

Tech gaps spreadsheet, ESDMD #1106 · ADD Rev C, pp. 78, 199, 257