Northwestern University — Freeze-Cast Porous Materials in Microgravity¶
Type: Academic Materials Science Research Group
PI: David Dunand (Professor of Materials Science, Northwestern University)
Related PIs: Kristen Scotti (PI on 94005), Katherine Faber (PI on STRG predecessor 4241)
Collaborators: University of Illinois Urbana-Champaign (CubeSat bus), Bradley University
Outcome Category: FO → CubeSat Mission → ISS Sample-Return → Open Data Repository
Investigated: Session 27, 2026-04-06
Updated: Session 98, 2026-04-07 — technologyOutcomes audit: [94005] "Advanced From" → [9322] (Precision Electrospray Thruster) is erroneous (different program, org, field). See TechPort Outcome Data Quality.
Summary¶
David Dunand's group at Northwestern used FO parabolic flights across 2 projects to develop freeze-casting of porous titanium and titanium oxide materials in microgravity. The technique — directionally solidifying suspensions to create aligned macropore structures — is sensitive to gravity-driven convection, making microgravity a scientifically productive environment. The FO flights generated fundamental data that: (1) was published in peer-reviewed journals, (2) led to selection for ISS testing in August 2016, (3) spawned the SpaceICE 3U CubeSat mission (undergraduate-led, NASA USIP-funded), and (4) produced the FreezeCasting.net open data repository (DOI: 10.5281/zenodo.545853). A separate STRG grant 4241 (PI Faber, same group) transitioned to both SBIR and Game Changing Development programs. This is a multi-program research arc from a single research group.
FO Projects¶
| Project | Title | TRL | Period | Status | PI |
|---|---|---|---|---|---|
| 94005 | Ti-Based Nanofoams for Dye-Sensitized Solar Cells | 4 → 6 | 2014-02 – 2015-09 | Completed | Kristen Scotti |
| 91340 | Freeze-cast Titanium Foams Testing | 5 → 5 | 2015-04 – 2017-08 | Completed | David Dunand |
Related non-FO project:
| Project | Title | TRL | Period | Program | Outcomes |
|---|---|---|---|---|---|
| 4241 | Tailorable Porous Ceramics via Freeze Casting | 2 → 3 | 2011-09 – 2015-08 | STRG | → SBIR + GCD transitions |
94005 description states "Work continued under T0149" (= 91340). The STRG project [4241] overlaps temporally with FO — likely the fundamental science grant while FO provided microgravity flight access.
What Was Tested¶
Freeze-casting process: Aqueous suspensions of TiO₂ (campaigns 1–2) and titanium metal (campaign 3) were directionally solidified during parabolic flight microgravity phases. The ice crystal growth template creates directionally aligned macropores. In 1-g, gravity-driven convection interferes with crystal growth; microgravity eliminates this, revealing the intrinsic solidification physics.
Key finding from description: "The research was selected for ISS testing in August 2016." This indicates the FO parabolic flights produced results compelling enough for ISS-duration experiments.
Downstream Impact¶
SpaceICE CubeSat Mission — STALLED¶
A 3U CubeSat designed to investigate freeze-casting in LEO, built as a partnership between Northwestern (experiment/payload), UIUC (satellite bus), and Bradley University. Funded through NASA's Undergraduate Student Instrument Project (USIP). Selected by CSLI for ELaNa launch in 2017.
Status (Session 35 update): Never launched. Sample containers (glass vials) cracked during development, causing the team to miss initial launch windows. A June 2019 Medill Reports article described students racing to finish before graduation, targeting April 2020 delivery. COVID likely delivered the final blow. Gunter's Space Page lists launch date as "202x" with launch vehicle "?" — no NORAD catalog ID exists. The undergraduate team cycled through graduation without completing the mission. Assessed as dead.
ISS Materials Lab Sample-Return Mission — STALLED¶
Through NASA's Materials Lab Open Science Campaign (grant NNH15ZTT002N), the group planned to send a freeze-casting experiment to the ISS using the PFMI (Pore Formation and Mobility Investigation) apparatus at NASA Marshall Space Flight Center. Unlike the CubeSat (in-situ analysis only), the ISS experiment would return solidified samples to Earth for microstructural characterization.
Status (Session 35 update): No evidence this experiment flew. The Dunand group website still describes it in future tense. PI Kristen Scotti completed her PhD and moved to Carnegie Mellon as a postdoc without ISS results. The group's microgravity publication trail ends with the 2017 Acta Materialia paper on parabolic flight data. Assessed as stalled — likely quietly dropped.
FreezeCasting.net Open Data Repository — DORMANT¶
The group created FreezeCasting.net (DOI: 10.5281/zenodo.545853), an open data repository for freeze-casting research (~800 papers as of 2017). Published a comprehensive review paper: Scotti & Dunand (2018), "Freeze Casting: A Review of Processing, Microstructure and Properties via the Open Data Repository, FreezeCasting.net," Progress in Materials Science, 94, 243-304.
Status (Session 35 update): No evidence of updates since 2017–2018. With Scotti at CMU as postdoc, active maintenance is unlikely. Static dataset remains accessible but not a living resource. A separate 2024 Nature Reviews Methods Primers article on freeze-casting (Wegst, Kamm, Yin, Garcia-Moreno — not Dunand's group) references the field broadly.
Publications¶
- TechPort library includes 2 document-type papers (files 364799, 364798)
- "The effect of solidification direction with respect to gravity on ice-templated TiO₂ microstructures" (file 364799)
- FreezeCasting.net review paper (file 364798)
- Description references: "Article (October 2017): A cheaper way to stock up in space" (Astronomy.com)
STRG → SBIR + GCD Transitions¶
The STRG predecessor [4241] has formal TechPort transitions to both SBIR/STTR and Game Changing Development programs. This is the rare case of a single research concept spanning 4 NASA programs: STRG → FO → SBIR → GCD.
Timeline¶
| Year | Event |
|---|---|
| 2011 | STRG grant begins (PI Faber, TRL 2→3) |
| 2014 | First FO project [94005]: TiO₂ parabolic flights (campaigns 1–2) |
| 2015 | Second FO project [91340]: titanium metal parabolic flights (campaign 3) |
| 2015 | STRG transitions to SBIR and GCD |
| 2016 | Selected for ISS testing (August 2016) |
| 2017 | FO project completes; FreezeCasting.net database published |
| 2017 | Media coverage: "A cheaper way to stock up in space" |
| 2017 | SpaceICE selected by CSLI for ELaNa launch |
| 2018 | SpaceICE vial cracking problem; misses launch window |
| 2019 | Students racing to finish before graduation (Medill Reports) |
| 2020+ | COVID disruption; SpaceICE never launches |
| 2024+ | Dunand group shifts away from space-related research |
Multi-program arc: STRG (2011) → FO (2014–2017) → ISS selection (2016) → SpaceICE (stalled) → ISS Materials Lab (stalled)
Assessment (Session 57 reconfirmation): The FO parabolic flights produced genuine science (Acta Materialia 2017, ice lens defect discovery). But both downstream missions stalled — SpaceICE died in undergraduate development, and the ISS experiment never materialized. The open data repository is the most durable legacy. This is Archetype: Research Dead End with Scientific Value — real findings that didn't propagate into operational capability. Session 57 web search confirms no new developments — Dunand group website still shows SpaceICE in historical/stalled state. No new microgravity publications from the group since 2018. The 2024 Nature Reviews Methods Primers freeze-casting review (Wegst et al.) does not cite microgravity results as a frontier. Assessment unchanged; page stable.
Verification¶
- Sample size: 2 FO projects + 1 STRG predecessor + SpaceICE CubeSat + ISS mission
- Query used:
techport_get_project(91340, 94005, 4241),techport_find_projects("freeze-casting SpaceICE"), web search for Dunand group - Counter-query: SpaceICE launch status — Gunter's Space Page lists "202x" with "?" vehicle. No NORAD ID. ISS experiment — Dunand group site still uses future tense; Scotti at CMU without ISS results.
- Confidence: Confirmed for FO→ISS selection, multi-program arc, and publications. Confirmed dead for SpaceICE CubeSat. Assessed stalled for ISS Materials Lab experiment.
Cross-References¶
- Related in-space manufacturing: Made in Space / Redwire (FDM→ISS AMF)
- Related materials science: FOMS/Mercury ZBLAN (optical fiber in microgravity)
- Related CubeSat missions: MIT TROPICS, JHU/APL VACNT→RAVAN
- Archetype: Research Infrastructure → Multi-Program Escalation — FO provided microgravity flight access that generated results compelling enough for ISS testing. The CubeSat and ISS missions are downstream consequences of FO validating the science.
Updated: Session 78, 2026-04-07 — No changes. SpaceICE still dead. FreezeCasting.net now inaccessible (connection refused). No new microgravity freeze-casting publications from any group. Field has moved on to terrestrial applications (frost-assisted freeze-casting, Advanced Materials Dec 2025). Page stable.