Mudawar Thermal Systems / Purdue — Cryogenic Heat Transfer for Mars ISRU¶
Last updated: Session 89, 2026-04-07
FO Projects (4):
| # | Project | Title | TRL | Period |
|---|---|---|---|---|
| 1 | 12243 | Flow Boiling + Condensation in Reduced-G | 3→5 | 2012-08 to 2015-08 |
| 2 | 184140 | Cryogenic Pool Boiling Reduced Gravity | 3→4 | 2025-09-01 to 2025-09-30 |
| 3 | 155235 | Spray HTC for Cryogenic Chilldown | 4→5 | 2023-02 to 2026-07 (active) |
| 4 | 106638 | Cryo Two-Phase Heat Transfer Coefficients | 4→6 | 2021-01 to 2026-06 (active) |
Lead Org: Mudawar Thermal Systems Inc. (Industry) / Purdue University
PI: Issam Mudawar (Purdue BTPFL)
Co-I: Jason Hartwig (NASA Glenn) on [155235] and [106638]
Technology: Cryogenic heat transfer correlations for reduced gravity
Outcome Category: Academic/Government R&D — STTR Phase III follow-on; Mars ISRU cryogenic processing
Session 20 correction: Mudawar has 4 FO projects (not 2). The arc spans 2012–2026 (14 years). Two active projects with GRC co-I Hartwig connect directly to the cryogenic cluster.
What Was Tested¶
Cryogenic pool boiling — the heat transfer process when a cryogenic liquid (e.g., LN2 as a propellant surrogate) boils on a heated surface — behaves very differently in reduced gravity. In microgravity, buoyancy doesn't drive bubble departure, so heat transfer correlations developed on Earth break down.
This STTR-II-E effort ran a single parabolic flight in September 2025 to measure cryogenic pool boiling heat transfer data in reduced gravity. The data fills a well-known gap: no comprehensive pool boiling curve for cryogenic fluids in partial and reduced gravity existed before this project. The complete pool boiling curve (from nucleate boiling through critical heat flux and into film boiling) is needed to design safe cryogenic heat exchangers for in-space propellant systems.
Why it matters for Mars: NASA's ISRU goals for Mars require producing, liquefying, and storing propellants (liquid oxygen, liquid methane) made from Martian resources. Designing the refrigeration and storage systems requires knowing how cryogenic fluids behave thermally under partial Martian gravity (0.38g) and orbital microgravity. The data from this project directly supports those designs.
Issam Mudawar — Academic Context¶
Issam Mudawar (Purdue University) is one of the world's leading heat transfer researchers with 400+ peer-reviewed publications. His Boiling and Two-Phase Flow Laboratory (BTPFL) at Purdue has been NASA's primary academic partner for microgravity flow boiling and pool boiling research for 20+ years.
Mudawar Thermal Systems Inc. is Mudawar's SBIR/STTR vehicle for federal R&D contracts. The "company" translates BTPFL research into government-contracted deliverables.
Key Purdue/Mudawar-NASA project: The Flow Boiling and Condensation Experiment (FBCE) on ISS — a multi-year ISS experiment studying flow boiling and condensation in microgravity, built with NASA Glenn and operational since 2021. FBCE test campaign completed in Q3 2024 after 2 years of active experiments. The facility remains on ISS for other researchers.
FBCE publications in 2025–2026: - "Pressure drop characteristics and prediction techniques for microgravity flow boiling onboard the ISS" — IJHMT Vol. 240, 2025 - "Method for generating a complete saturated pool boiling curve for cryogenic fluids under terrestrial gravity" — IJHMT Vol. 243, 2025 (with Ahmad, Foster, Kim, Meyer, Hartwig) - "Critical Heat Flux of Cryogenic Flow Boiling under Terrestrial, Partial, and Reduced Gravity Conditions" — IJHMT Vol. 245, 2025 (Kim, Hartwig, Damle, Foster, Darges, Mudawar) — extends CHF correlations across gravity levels - "Experimental investigation of LN2 pool boiling critical heat flux (CHF)" — IJHMT Vol. 254, 2026 (received May 2025, accepted Jul 2025) - AIAA SciTech 2025: Two conference papers — "Flow Visualization of LN2 Flow Boiling in Horizontal Heated Tubes" (Kim et al.) and "Effect of Flow Orientation on LN2 Nucleate Boiling Heat Transfer" (Hartwig et al.)
The FO pool boiling project is complementary to FBCE: FBCE studies flow boiling (propellant flowing through channels); the FO project studies pool boiling (propellant in a tank touching a heated surface). Together, the FBCE ISS completion + FO parabolic flights give Mudawar's lab the most comprehensive cryogenic heat transfer dataset in microgravity ever assembled.
Upstream Lineage¶
- 2021: NASA SBIR Phase I ($124.7K, 80NSSC21C0266) — "Heat Transfer Correlations for Complete Cryogenic Pool Boiling Curve"
- 2022–2026: NASA STTR Phase II ($749.3K, 80NSSC23CA009) — "Advanced Concepts for Lunar and Martian Propellant Production, Storage, Transfer, and Usage"
- 2025-09: FO parabolic flight (1 month) — reduced gravity measurements
- 2025 publications:
- "Experimental investigation of LN2 pool boiling critical heat flux (CHF)" — IJHMT 2025
- "Method for generating a complete saturated pool boiling curve for cryogenic fluids under terrestrial gravity" — IJHMT Vol. 243
- Multiple other 2025 papers on cryogenic and microgravity heat transfer
Downstream / Post-FO¶
Direct follow-on: NASA STTR Phase III
Award: 80NSSC26C0007 | $366.6K | 2026-04-15 – 2027-04-14
Description: "Heat Transfer Correlations for Complete Cryogenic Pool Boiling Curve — Gregory Peters Fund"
This Phase III award started April 15, 2026 — two weeks after today's session. The FO flight (September 2025) produced the reduced-gravity data that completes the experimental dataset; the Phase III converts that data into engineering correlations usable by NASA mission designers.
The "Gregory Peters Fund" designation in the award suggests this is memorial/named funding within NASA — not unusual for specialized fundamental research.
Total Contracts (Tracked)¶
| Agency | Award | Amount | Notes |
|---|---|---|---|
| NASA | 80NSSC21C0266 | $124.7K | SBIR Phase I, pool boiling correlations |
| NASA | 80NSSC23CA009 | $749.3K | STTR Phase II, Lunar/Mars propellant |
| NASA | 80NSSC26C0007 | $366.6K | STTR Phase III (just started Apr 2026) |
| DoD/Navy | N0003910C0078 | $653.6K | Phase II effort |
| DoD/Navy | N0001409C0095 | $498.4K | R&D |
| DoD/Navy | N0001407M0395 | $99.9K | Smaller efforts |
| Total tracked | ~$2.5M |
Outcome Assessment¶
Confidence: Confirmed (publication chain) | Confirmed (Phase III follow-on)
Outcome: Academic R&D — peer-reviewed publications + STTR Phase III ($366.6K)
This is the smallest-dollar clean outcome in the portfolio, but the causal chain is tight: FO flight → missing data point in the pool boiling curve → Phase III funding to produce correlations → engineering tool for NASA cryogenic designers. Issam Mudawar's academic reputation ensures the correlations will be used.
The TRL gain (3→4) reflects the appropriate outcome: fundamental measurements in reduced gravity are early-stage work. There is no product to commercialize; the output is knowledge.
Archetype: Academic professor's R&D vehicle uses FO to close a fundamental physics data gap, leading to publications and next-phase government funding. Modest dollar amounts; high scientific credibility.
Time dimension:
- 2021: SBIR Phase I pool boiling correlations work begins
- 2025-09: FO parabolic flight (1 month) — reduced gravity measurements
- 2025: Multiple publications from the combined dataset
- 2026-04: STTR Phase III begins ($366.6K)
Sources¶
- TechPort: 184140
- USASpending: 80NSSC26C0007 ($366.6K Phase III), 80NSSC23CA009 ($749.3K Phase II)
- Mudawar BTPFL publications: https://engineering.purdue.edu/mudawar/articles-all/
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Purdue news (2023): https://www.purdue.edu/newsroom/2023/Q4/science-enabling-heat-and-air-conditioning-for-long-term-space-habitats-is-almost-fully-available/ Session 59 update — STTR Phase III now active + Artemis II context: The STTR Phase III award (80NSSC26C0007, $366.6K) is now active as of April 15, 2026 — converting FO parabolic flight data into engineering correlations for NASA mission designers. Additionally, 2 new AIAA SciTech 2025 conference papers and 1 new IJHMT Vol. 245 journal article (Kim et al., cryogenic flow boiling CHF across gravity levels) were identified, bringing the total recent publication count to 5+ in 2025-2026. The Artemis II crew broke the Apollo 13 distance record on April 6, 2026 (252,756 mi) with splashdown scheduled April 10 — the ICPS cryogenic stage uses the same propellant physics that Mudawar's lab characterizes.
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Session: 2026-04-06 (Session 9)
Session 89 update (2026-04-07): No significant changes since Session 59. TechPort projects [155235] and [106638] still active with same TRL values. [106616] (tank coatings) now shows Completed in TechPort (TRL 4 — did not reach target 6; this is the weakest of the 4 Mudawar FO projects by outcome). STTR Phase III ($366.6K) still active. No new publications beyond those captured in Session 59. Artemis II still in flight (splashdown NET April 10, 2026).