Vaporizing liquid microthruster

MEMS technology is expanding into increasingly diverse applications. As par t of a micropropulsion system, microthruster attitude controls have been mi cromachined in silicon. This paper presents the microthruster design, fabri cation, and test results. Fluid injected into a microchamber is vaporized b y resistive silicon heaters. The exiting vapor generates the thruster force as it exits a silicon micro-nozzle. The vaporization chamber, inlet and ex it nozzles were fabricated using anisotropic wet etching of silicon. With a 5 W heater input, injected water could be vaporized for input flow rates u p to a maximum of 0.09 cc/s. Experimental testing produced thruster force m agnitudes ranging from 0.15 mN to a maximum force output of 0.46 mN dependi ng on fabrication parameters: chamber length, nozzle geometries, heater pow er, and liquid flow rates. (C) 2000 Elsevier Science S.A. All rights reserv ed.