Prototyping and experimental characterization of a micropropulsion system based on supersonic cold-gas and warm-gas micronozzles

This paper reports the latest results obtained during the development of a micropropulsion system based on supersonic cold-gas and warm-gas micronozzles for attitude control of micro and nanosatellites for a thrust of the order of 100 microN to 1 mN. The micronozzles have been manufactured by means of nanolithography and Reactive-Ion Etching and are assembled with the other MEMS components in microthruster modules, each able to produce up to 4 thrust vectors with minimum pulse of 100 ms fully adjustable from 0 to 100% of thrust. The integration of a resistor in the module enables the increase of specific impulse by heating the gas before the micronozzle. Measurements of thrust under vacuum condition have been performed by means of a specifically designed microbalance. The comparison between the experimental data and the CFD simulation has been used to study the effect of the losses in the nozzle in order to select the best geometry. Specific impulses between 30 s and 100 s have been observed under different heating conditions. The complete micropropulsion system including tank, valves, piping and thruster modules for application on 3 axis stabilization of micro and nanosatellites has been designed and is in course of prototyping. This work is included in a research program aiming at the realization of efficient micropropulsion devices and systems enabling full 3 axis stabilization as well as orbital maneuver capability for nano and microsatellites.