MICRONEWTON/MILINEWTON- RIT, CHARACTERIZATION TEST IN EPL, ESTEC

摘要

Some new band of future ESA missions need small thrusters in two different thrust level. EO missions like EarthCare, Swarm and Earth Gravity Mission like Satellite to Satellite Tracking would require a level of few milinewton down to few tenth of milinewton with a thrust controllability of few μN for Formation flying missions like DARWIN and PROBA 3 and fine positioning missions necessitate strict requirements on thrust level, thrust controllability and noise, life time and reliability. The RIT technology provides a suitable benchmark to scale down the thrusters and thrust levels, as due to their principle, the electrode-less rf-ionizer might be miniaturized without mechanical problems. The Giessen EP-group undertakes in cooperation with EADS a R & D-program to develop mini RF ion thrusters. Due to its modular design, μNRIT-4 can be used with a minimum of modifications in both thrust regimes. Recently this thruster has been characterized in the CORONA facility of the ESA Propulsion Laboratory in ESTEC. This paper presents the results of this test campaign including thrust controllability. As this test was performed with high precision electronic system and gas flow controller we are possible now to calculate precisely the thrust and thrust stepping. The measurements of beam profile performed with the EPL beam diagnostics system allowed to determinate the divergence of the plume and the geometric factor of the thrust. The measured narrow beam divergence indicates a low risk of Spacecraft contamination.