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.