Purdue University — FEMTA Water Micropropulsion¶

Last updated: Session 95, 2026-04-07

Summary¶

Purdue developed FEMTA (Film-Evaporation MEMS Tunable Array) — a water-based microthruster for CubeSat attitude control that uses surface tension and micro-heaters instead of toxic propellants. TRL 4→6 over a 6-year FO project (2019–2025). Flew on Blue Origin New Shepard (NS-29, January 2025). High community interest (2,742 views). Student-designed payload ("Purdue's first space mission"). No commercial spinoff yet, but multiple SmallSat conference papers and a potential open-source low-cost attitude control system for university CubeSats.

FO Project¶

Field	Value
Project	106637
Lead Org	Purdue University
PI	Alina Alexeenko
Co-I	Steven H. Collicott
TRL	4→6
Period	2019-01 to 2025-01
TX	TX01.1.7: Cold Gas
Destinations	Earth, Moon and Cislunar, Mars
Views	2,742

Technology¶

FEMTA uses silicon-and-glass MEMS chips (1 cm × 1 cm × 1 mm) with arrays of micrometer-scale capillaries. Deionized water is the propellant — safe, dense, and abundant. The operating principle:

Surface tension holds water in the capillaries (no valves needed)
Small heaters near capillary ends create water vapor
Vapor produces tunable, controllable thrust
Power requirement: <1 W per axis

Key specs: - Mass and thrust-to-power ratio significantly below current CubeSat propulsion - Demonstrated CubeSat rotation at ~5°/sec slew rate with <1 W input - Non-toxic (water) — eliminates hydrazine handling requirements - Fits in <0.5U volume

Why it matters: Reaction wheels and cold-gas thrusters are cost-prohibitive for university and developing-nation CubeSat programs. A $50 MEMS chip using distilled water could democratize precision attitude control for smallsats.

Flight Heritage¶

Blue Origin New Shepard NS-29 (January 28, 2025): Students from Purdue designed, built, and tested the FEMTA suborbital payload. This was described as "Purdue's first space mission" in the AAE Aerogram 2025-2026. The flight validated FEMTA's passive propellant delivery system and thruster performance in microgravity.

Parabolic flights: Earlier FO campaigns included parabolic flights to characterize FEMTA in brief microgravity windows before the full suborbital test.

Downstream Impact¶

Academic Output (confirmed)¶

SmallSat Conference 2017: "Quad-Thruster FEMTA Micropropulsion System for CubeSat 1-Axis Control"
SmallSat Conference 2022: "Thermal Modeling of FEMTA Micropropulsion System for CubeSat Attitude Control" + "Propellant Management of Water-Based Microthruster for Suborbital 0G Testing"
SpaceNews feature: "Water propulsion technologies picking up steam" — covered FEMTA among emerging water-based propulsion systems
Purdue dissertations/theses: "Characterization of the FEMTA Microthruster for CubeSat Proximity Operations" (2024); "Micropropulsion Trade Study and Investigation for Attitude Control" (Katherine Fowee)

Educational Impact (confirmed)¶

Multiple Purdue courses built around FEMTA: - VIP 479: FEMTA Suborbital Flight Test (Fall 2023) - AAE 490: FEMTA Orbital Flight Test (Spring 2022)

This is a significant educational pipeline — students get hands-on experience designing, building, and flying space hardware through the FO program.

6th Generation Performance (confirmed)¶

Sixth-generation FEMTA devices have been demonstrated to produce >300 μN of thrust per 1 W of electrical power at 90 seconds Isp. These devices enable direct visualization of liquid–vapor interfaces during operation — a diagnostic capability that validates the propellant management system design.

Orbital Flight Demonstration (in development)¶

A complete FEMTA six degree-of-freedom propulsion system including zero-gravity propellant management is being developed at Purdue in preparation for a future orbital flight demonstration. Purdue students are designing, building, and testing a FEMTA propulsion system and CubeSat for orbital launch as part of coursework (AAE 490: FEMTA Orbital Flight Test, first offered Spring 2022). No launch date confirmed.

Commercial Potential (not yet realized)¶

No USASpending contracts for FEMTA commercialization. No startup or commercial product identified. The technology is competitive with other water-based CubeSat propulsion systems (e.g., Phase Four, Benchmark Space Systems, Bradford Space) but FEMTA's specific advantage is ultra-low cost and power for attitude control rather than orbit changing.

Market comparison: Commercial CubeSat reaction wheels cost $5K–$50K. If FEMTA can deliver reliable 3-axis attitude control for <$500, it could be disruptive for the educational/university CubeSat segment (~50+ missions/year globally).

PI Profile¶

Alina Alexeenko — Full Professor, Purdue School of Aeronautics and Astronautics. Research in rarefied gas flow phenomena, smallsat propulsion, spacecraft contamination, plume interactions. FEMTA is her signature space propulsion project.

Steven H. Collicott — Co-I; Purdue AAE professor specializing in capillary fluid mechanics in low gravity. Also co-I on other FO projects ([106655] Purdue surgical facility).

Significance¶

Archetype: University Technology Demonstrator — FO provides the flight test opportunity that university researchers can't afford independently. The educational value (student payload design, courses, theses) may exceed the technology transfer value.

Water propulsion is a market trend. Multiple companies are developing water-based spacecraft propulsion. FEMTA's MEMS approach is the smallest and lowest-power variant. The open-source potential could make it the "Arduino of CubeSat attitude control."

6-year timeline is notable. 2019–2025 is long for an FO project. The delay likely reflects COVID disruptions and Blue Origin New Shepard scheduling constraints.

Surprise level: LOW — Expected a university technology demo. The New Shepard flight confirmation and educational pipeline depth were positive findings, but no commercial outcome.

Verification¶

Sample size: 1 FO project, 1 PI
Queries: techport_get_project [106637]; web search "Purdue FEMTA Alexeenko water micropropulsion New Shepard"
Evidence: NS-29 flight confirmed (SatNews, Purdue Aerogram 2025); SmallSat papers confirmed (USU DigitalCommons); SpaceNews coverage confirmed
Counter-query: Has any FEMTA unit been selected for an orbital CubeSat mission? (Purdue listed AAE 490 "FEMTA Orbital Flight Test" course in Spring 2022, suggesting orbital ambitions, but no confirmed orbital mission found)
Confidence: Confirmed for technology demonstration; speculative for commercial or orbital deployment

Cross-References¶

UC Davis HDD Reaction Wheels — same problem space (low-cost CubeSat attitude control), different approach (repurposed hard drives vs MEMS water thrusters)
Busek Company — commercial CubeSat propulsion (BIT-3 iodine); different market segment (orbit change vs attitude control)
Purdue Surgical Facility — same co-I (Collicott); Purdue has multiple FO projects