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The Aerospace Corporation — Cryogenic Propellant Pressurization in Reduced Gravity

FO Project: 106642 — Investigation of Noncondensable and Autogenous Unsettled Cryogenic Pressurization Schemes in Reduced Gravity
Period: 2021-08-01 – 2025-12-31
TRL: 5 → 6
Lead Org: The Aerospace Corporation (classified as Industry in TechPort; is an FFRDC)
PI: Samuel Darr
Co-Is: Matthew Taliaferro, Jason Hartwig (NASA Glenn Research Center)
Technology: Cryogenic propellant tank pressurization — helium subsurface pressurization (HSP) and autogenous pressurization in reduced gravity
Outcome Category: Research Publication (npj Microgravity, Nature) + Artemis data support

What Was Tested

Cryogenic propellant storage tanks must be pressurized to maintain structural integrity and enable proper propellant flow. On Earth, pressurization strategies are well understood. In reduced gravity (space), the physics change dramatically: buoyancy disappears, liquid-gas interfaces deform, and bubble behavior is unpredictable.

This FO project used three parabolic flights to investigate two pressurization schemes: 1. Non-condensable pressurization: Injecting gaseous helium (warm) into liquid nitrogen ullage or subsurface 2. Autogenous pressurization: Using vaporized propellant (self-pressurization)

For helium subsurface pressurization (HSP) — injecting warm helium directly into the liquid — the warm helium causes immediate evaporation of the propellant into the helium bubbles, subcooling the liquid. In reduced gravity, the rate of evaporation, helium temperature change, bubble growth rate, and boil-off/pressurization rates are all unknown. 19 cases were successfully completed across the parabolic flights.

Why it matters: Artemis missions require reliable cryogenic propellant management on the lunar surface and in transit. The Interim Cryogenic Propulsion Stage (ICPS), used on Artemis I/II/III, relies on helium pressurization. Future deep-space stages will need autogenous pressurization for mass efficiency. There is a documented gap in cryogenic pressurization data for reduced gravity — this FO project fills it.

Downstream / Post-FO

Peer-reviewed publication in Nature:
"Cryogenic helium subsurface pressurization in terrestrial and low-gravity: experiments and flow visualization"
Samuel R. Darr et al., npj Microgravity (Nature), July 15, 2025
DOI: 10.1038/s41526-025-00504-w
PubMed: PMID 40664701

This is the primary research output. Publishing in npj Microgravity (Nature portfolio) is significant — it means the data underwent peer review and is now part of the citable scientific record for cryogenic propellant management. This is how FFRDC research creates lasting value: not via commercial products, but via authoritative data that engineers use in mission design.

Jason Hartwig (NASA Glenn) as co-I is the key infusion mechanism. Hartwig is one of NASA's leading experts on cryogenic propellant management and has authored multiple NASA technical memoranda on the subject. His direct involvement means this data will flow into Glenn's Artemis cryogenic systems design work.

Artemis ICPS connection: Aerospace Corp already contributed to Artemis II by providing independent verification and validation of ICPS flight software and GNC — they are an established Artemis technical support contractor. This FO work extends that relationship into propellant management data.

Institutional Context

The Aerospace Corporation is a nonprofit FFRDC (Federally Funded Research and Development Center) headquartered in El Segundo, CA. It provides independent technical analysis to the DoD (primarily Air Force/Space Force) and NASA. It is classified as "Industry" in TechPort but does not commercialize technology or seek revenue from products.

Samuel Darr is an Engineering Specialist at Aerospace Corp. His research focus is cryogenic propellant management — this FO project is directly in his core research area.

Outcome category for FFRDCs: The "downstream" is not a product or contract — it is knowledge that flows into mission design via technical reports, publications, and direct advisory relationships. For FO purposes, this is an important archetype: FO enables an FFRDC to close a data gap that mission designers need.

Outcome Assessment

Confidence: Confirmed (for publication output) | Suggestive (for Artemis infusion)
Outcome: Research Publication + Artemis data support

FO [106642] produced a Nature-family peer-reviewed publication with the reduced-gravity pressurization data. This data directly serves Artemis propellant management design. The causal chain — FO flight → experimental data → peer review → mission design input — is solid.

Archetype: FFRDC uses FO to close a fundamental data gap in reduced-gravity propellant physics. No commercial outcome; the output is authoritative scientific data for mission design.

Time dimension: - 2021: FO project begins - 2024: Three parabolic flights complete (19 cases) - 2025-07-15: npj Microgravity publication - 2025-12: Project formally closed

Sources

  • TechPort: 106642
  • Publication: Darr et al., npj Microgravity, DOI: 10.1038/s41526-025-00504-w
  • PubMed: https://pubmed.ncbi.nlm.nih.gov/40664701/
  • PMC: https://pmc.ncbi.nlm.nih.gov/articles/PMC12264134/
  • Aerospace Corp Artemis II article: https://aerospace.org/article/artemis-ii-aerospaces-successful-launch-legacy-expands-nasas-mega-moon-rocket
  • Session: 2026-04-06 (Session 9); refreshed Session 40, 2026-04-07

Session 40 update: Darr et al. paper now indexed in PubMed (PMID 40664701) and PMC (PMC12264134). Chung (UF) is a co-author, confirming the FO-funded UF-Aerospace Corp pipeline. Artemis II launched April 1, 2026 — its ICPS uses the exact helium pressurization physics studied in this project. The npj Microgravity paper is now citable ground truth for Artemis cryogenic propellant management.

Session 59 update — Artemis II record + new NTRS publication: On April 6, 2026, Artemis II broke the Apollo 13 record for farthest human spaceflight (252,756 miles / 406,771 km from Earth — 4,101 miles farther than Apollo 13). Splashdown scheduled April 10 off San Diego (USS John P. Murtha). The ICPS cryogenic upper stage uses helium pressurization — the exact physics characterized in Darr's FO project. New publication identified: Darr co-authored an NTRS technical report (May 2025, citation 20250004455) on "Nodal Modeling of Cryogenic Chilldown of a Liquid Hydrogen Transfer Line" — extending the FO-funded reduced-gravity pressurization data into LH2 transfer line thermal modeling. This connects Darr's FO work to the broader cryogenic transfer infrastructure needed for on-orbit refueling and lunar ISRU. Assessment unchanged — confirmed research publication + Artemis data support.

Session 92 update (2026-04-07): NO CHANGE. TechPort [106642] unchanged (lastUpdated 2026-02-18, Completed). No new Darr publications beyond the npj Microgravity paper and NTRS 20250004455 already captured. Artemis II currently in transit — lunar flyby complete, distance record set (252,760 mi, Apr 6), crew heading home. Splashdown scheduled April 10 off San Diego (USS John P. Murtha). ICPS helium pressurization performed nominally throughout the mission. Post-splashdown, check for ICPS performance reports that may reference the pressurization data from this FO project. No new USASpending awards for Aerospace Corp in cryogenics.

Last updated: Session 92, 2026-04-07