Miniature satellite propulsion system uses water vapor

August 08, 2017 // By Jean-Pierre Joosting
Miniature satellites called CubeSats can benefit from a new type of micropropulsion system developed by researchers at Purdue University (West Lafayette, IN) that uses an innovative design of tiny nozzles that release precise bursts of water vapor to maneuver the spacecraft.

Low-cost "microsatellites" and "nanosatellites" far smaller than conventional spacecraft, have become increasingly prevalent. Thousands of the miniature satellites might be launched to perform a variety of tasks, from high-resolution imaging and internet services, to disaster response, environmental monitoring and military surveillance.

"They offer an opportunity for new missions, such as constellation flying and exploration that their larger counterparts cannot economically achieve," said Alina Alexeenko, a professor in Purdue University's School of Aeronautics and Astronautics.

However, to achieve their full potential, CubeSats will require micropropulsion devices to deliver precise low-thrust "impulse bits" for scientific, commercial, and military space applications.

The new system, called a Film-Evaporation MEMS Tunable Array, or FEMTA thruster, uses capillaries small enough to harness the microscopic properties of water. Because the capillaries are only about 10 micrometers in diameter, the surface tension of the fluid keeps it from flowing out, even in the vacuum of space.

Activating small heaters located near the ends of the capillaries creates water vapor and provides thrust. In this way, the capillaries become valves that can be turned on and off by activating the heaters. The technology is similar to an inkjet printer, which uses heaters to push out droplets of ink.

The research paper was authored by graduate student Katherine Fowee; undergraduate students Steven Pugia, Ryan Clay, Matthew Fuehne and Margaret Linker; postdoctoral research associate Anthony Cofer; and Alexeenko.


Purdue University graduate student Katherine Fowee and postdoctoral research associate Anthony Cofer work on a new micropropulsion system for miniature satellites called CubeSats. Image courtesy of Purdue University photo/Erin Easterling.