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University of Florida — Jacob Chung Cryogenic Propellant Management

Last updated: Session 89, 2026-04-07

Summary

Jacob Chung at the University of Florida has 5 FO projects studying cryogenic propellant behavior in microgravity — tank inner surface coatings to reduce boiloff and pool boiling/pressurization dynamics. His 30+ years of cryogenic fluid management research for NASA earned him the NASA Exceptional Public Service Medal (June 2024) — the highest honor NASA bestows on non-employees. The FO work produced 6+ publications (including multiple npj Microgravity papers) and directly feeds Artemis cryogenic propellant management design data.

FO Projects

# Project Title TRL Period Library Items
1 91356 Near-Zero Gravity Cryogenic Line Chilldown (sRLV) 4→5 2014-07 to 2018-05 —
2 106581 Optimal Chilldown Methods for Cryo Propellant Tanks 4→6 2018-01 to 2021-05 —
3 106713 Cryogenic Pool Boiling and Subsurface He Pressurization 4→6 2019-12 to 2024-03 2
4 106616 Cryogenic Propellant Storage Tank Inner Surface Coating 4→5 2021-12 to 2025-08 6 (5 papers + 1 more)
5 89415 Revolutionary Approach for Efficient Microgravity Transfer Line Chilldown 4→6 2016-08 to 2019-05 —

Session 20 correction: 5th Chung project [89415] discovered — extends arc back to 2016. This project develops novel chilldown approaches using multi-scale surface modifications to reduce cryogenic transfer waste.

Co-Is: Samuel Darr (also appears in Aerospace Corp Cryogenics); Matthew Taliaferro

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Technology

The Boiloff Problem

Cryogenic propellants (liquid hydrogen, liquid oxygen, liquid methane) boil off in space because: 1. External heat leaks through tank walls 2. In microgravity, boiling behavior is fundamentally different — no buoyancy to drive vapor bubbles away from heated surfaces 3. During pressurization, helium injected into liquid can cause additional boiling

For Artemis missions requiring long-duration cryogenic storage (weeks to months), boiloff represents significant propellant loss. Understanding and mitigating this is critical for lunar and Mars architectures.

Tank Coating Innovation [106616]

Chung's team tested 4 advanced coating materials applied to the inside of cryogenic propellant tanks: - Aluminum and stainless steel substrates (emulating common spacecraft tank designs) - Thin-film coatings that actively suppress boiling — fundamentally different from conventional external insulation - Combined with flow pulsing technique — periodic flow perturbation that enhances heat transfer during chilldown

Key result: Coatings reduced cryogenic boiloff in reduced gravity, with the combination of coating + flow pulsing being more effective than either alone.

Pool Boiling + Pressurization [106713]

Tested cryogenic pool boiling for flight-like tank surfaces (surface roughness and shapes matching actual spacecraft tanks) and characterized subsurface helium pressurization dynamics. Prior data didn't reflect real tank geometries — this closes a critical data gap.

Publications from FO Work

The [106616] project has 6 library items — an unusually high publication output for an FO project:

  1. "The effect of reduced gravity on cryogenic nitrogen boiling and pipe chilldown" — npj Microgravity
  2. "An advance in transfer line chilldown heat transfer of cryogenic propellants in microgravity using microfilm coating" — npj Microgravity
  3. "Cryogenic spray quenching of simulated propellant tank wall using coating and flow pulsing in microgravity" — PMC/journal paper
  4. "Effects of microgravity on cryogenic spray quenching with enhancement by surface coating and flow pulsing" — SSRN/journal
  5. "Nitrogen flow boiling and chilldown experiments in microgravity using pulse flow and low-thermally conductive coatings"
  6. Additional publication

This publication volume reflects 30+ years of research program infrastructure — Chung's lab can rapidly process flight data into journal papers because the analysis pipeline is mature.

Session 40 update — New 2025 zero-G flights: UF announced (Jul 2025) that Chung's team completed new zero-gravity parabolic flight experiments on May 2 and May 5, 2025, testing four advanced coating materials applied to the inside of cryogenic propellant tanks. These flights are part of the ongoing [106616] arc and produced new reduced-gravity data on boiloff suppression.

Session 40 update — Darr collaboration paper: Samuel Darr (Aerospace Corp, former Chung student) co-authored the npj Microgravity (Nature) paper "Cryogenic helium subsurface pressurization in terrestrial and low-gravity" (DOI: 10.1038/s41526-025-00504-w, Jul 2025) with Chung. This confirms the active Chung→Darr→Aerospace Corp pipeline — FO-funded lab relationships generating peer-reviewed data for Artemis.

Session 40 update — Artemis II launched: Artemis II launched April 1, 2026 (10-day crewed lunar flyby). The ICPS uses cryogenic LOX/LH2 propellants with helium pressurization — the same physics Chung's lab has studied across 5 FO projects. Chung's boiloff suppression coatings are directly relevant to future Artemis long-duration cryogenic stages (EUS).

Session 59 update — Artemis II record + additional flights planned: On April 6, 2026, the Artemis II crew broke the Apollo 13 record for farthest human spaceflight, reaching 252,756 miles (406,771 km) from Earth — 4,101 miles farther than Apollo 13 in 1970. Splashdown is scheduled April 10, 2026 off San Diego (USS John P. Murtha recovery). The ICPS cryogenic upper stage that enabled this trajectory uses the exact helium pressurization and LOX/LH2 thermal management physics that Chung's 5 FO projects have studied. New development: UF announced (Jul 2025) that Chung's team plans to apply for two additional FO flights to test more coating candidates beyond the 4 materials tested in the May 2025 flights. If awarded, this would extend the Chung FO arc to 7 projects and ~15 years (2014–2028+).

Downstream Impact

NASA Exceptional Public Service Medal (confirmed)

Awarded June 2024 by NASA Glenn Research Center Awards Office. Citation: "exceptional, sustained, and multi-faceted contributions advancing NASA's in-space cryogenic fluid management science and technologies over multiple programs and 30 years."

This is the highest honor NASA bestows on individuals who are not NASA employees. It recognizes the cumulative impact of Chung's cryogenic research program, which includes but extends beyond the FO projects.

Artemis Cryogenic Propellant Management (confirmed — feeds data)

Chung's FO data directly feeds Artemis-era design decisions: - Exploration Upper Stage (EUS): long-duration cryogenic storage for lunar transit - Lunar Gateway propulsion: cryogenic transfer and storage in cislunar orbit - Human Landing System (HLS): cryogenic propellant management for landers

The specific coating and flow pulsing techniques validated in FO could reduce boiloff, improving propellant budgets for deep-space missions.

Connection to Broader Cryogenic Research Community

Co-I Samuel Darr also appears in the Aerospace Corp Cryogenics FO project, which published its own npj Microgravity paper (July 2025). This connects Chung's UF work to the broader FO cryogenic cluster — multiple institutions using FO parabolic flights to build the Artemis-era cryogenic knowledge base.

PI Profile

Jacob N. Chung — Distinguished Professor, UF Department of Mechanical and Aerospace Engineering. Member of the Astraeus Space Institute. Born in Taiwan; came to the US for graduate school. Has led NASA-supported cryogenic fluid management research since 1992. Specializes in in-space thermal-fluid management for chemical rocket propulsion. His work focuses on optimizing propellant use in rocket engines for long-distance exploration.

Dollar Tracking

Source Amount Notes
NASA FO (2 projects) — Within FO program budget; exact amounts not public
NASA Glenn (30-year research program) Substantial but untracked Career-spanning grants supporting cryogenic research

Significance

Archetype: Career-Spanning Research Program → Artemis Data Foundation — Chung's FO projects are not one-off experiments. They are the microgravity validation component of a 30-year cryogenic research program. FO provides the reduced-gravity data that validates his lab's models and coating technologies.

Publication density is the metric. 6 library items from 2 FO projects is among the highest in the FO portfolio. For knowledge-payload projects, publications are the primary output — and Chung's lab converts flight data into papers with exceptional efficiency.

The NASA Exceptional Public Service Medal is the validation. NASA doesn't give its highest non-employee honor lightly. The citation explicitly credits the multi-program, multi-decade nature of the contributions — FO is one piece of a larger body of work that NASA considers mission-critical.

FO cryogenic cluster: Chung (UF), Darr (Aerospace Corp, [106642]), Collicott (Purdue, [106602]), Mudawar (Purdue MTSI, [184140]), Creare ([155234], [158702]), and Carthage College MPG ([94131] et al.) form a coherent FO cryogenic fluid management research community. Their combined work builds the data foundation for Artemis propellant systems.

Surprise level: MEDIUM — Expected a prolific academic. The NASA Exceptional Public Service Medal and the 6-publication output from 2 FO projects exceeded expectations.

Session 89 update (2026-04-07): No significant changes since Session 59. All 5 TechPort projects unchanged. [106616] (coatings) now shows Completed (TRL 4). No new publications found. Artemis II still in flight — splashdown NET April 10. The proposal for 2 additional FO flights (mentioned in UF Jul 2025 news release) has not yet appeared in TechPort.

Verification

  • Sample size: 2 FO projects, 1 PI
  • Queries: techport_get_project batch [106616, 106713]; web search "Jacob Chung University Florida NASA award 2024 cryogenic"
  • Evidence: UF news (July 2024) confirming NASA Exceptional Public Service Medal; UF MAE department announcement; Focus Taiwan article; npj Microgravity papers confirmed via Nature.com; PMC paper confirmed
  • Counter-query: Did Chung receive the medal specifically for FO work? No — the citation credits 30 years across multiple programs. FO is one component.
  • Confidence: Confirmed for publications, NASA medal, and Artemis relevance; suggestive for specific design adoption of coating technology

Cross-References