A vaporizing water micro-thruster

Vaporizing water micro-thrusters are fabricated and tested. A single micro-thruster we developed, fabricated by MEMS technologies, consists of a microresistor, a vaporizing chamber, a nozzle, a propellant inlet and a micro channel. The water propellant is fed into the thruster from a propellant tank by capillary force and pressure. The micro-thruster works in a pulse mode. During each period, an electric pulse is applied on the micro-resistor to heat the water in the chamber to vaporize it into high-pressure gas. A thrust is then produced as the gas exits through the nozzle. Test results show that for a single micro-thruster with pulse power of 48 W, the total impulse produced in a second is more than 0.2/spl times/10/sup -6/ N/spl middot/s.