A hybrid cold gas microthruster system for spacecraft

A hybrid cold gas microthruster system suitable for low Deltav applications on spacecraft have been developed. Microelectromechanical system (MEMS) components together with fine-mechanics form the microthruster units, intergrating four independent thrusters. These are designed to deliver maximum thrusts in the range of 0.1-10 mN. The system includes three different micromachined subsystems: a nozzle unit comprising four nozzles generating supersonic gas velocity, i.e. 455 m/s, four independent piezoelectric proportional valves with leak rates at 10(-6) scc/s He, and two particle filters. The performances of all these MEMS subsystems have been evaluated. The total system performance has been estimated in two parameters, the system-specific impulse and the mass ratio of the propulsion system to the spacecraft mass. These figures provide input for spacecraft design and manufacture. (C) 2002 Elsevier Science BN. All rights reserved.