Performance test of micro ion thruster using microwave discharge

Several types of electric propulsions have been developed and used for artificial satellites on geostationary orbit keeping or planetary exploration. A series of small-scale satellites is recently expected to be used instead of traditional large-scale satellites for reducing launch cost and risk. The trend towards needs of small spacecraft requires micro thrusters with high specific impulse. In this study, a micro ion engine utilizing a microwave discharge plasma was fabricated and was tested. This ion engine comprises some components, such as electrostatic grids, antenna, and microwave power supply, which decide its performance. The performance dependence on the components was examined under several experimental conditions. The typical performance parameters of the engine were ion production cost of 770 V, propellant utilization efficiency of 72%, and thrust of 0.66 mN in conditions of input 2.45 GHz microwave power of 8 W and propellant (xenon gas) flow rate of 0.2 sccm with a star type antenna.