Radio-frequency ion sources for space propulsion (invited)

Abstract

After more than 25 years of research, development, and qualification work at Radiofrequency Ion Thrusters, so-called RIT, the RIT 10 engine, designed for north–south stationkeeping of geosynchronous satellites, is now ready for a space test onboard the European Retrievable Carrier EURECA. Since two years, the European Space Agency ESA/ESTEC is working at a new technological satellite, called ARTEMIS, at which ion propulsion shall be used operationally for north–south stationkeeping. In the scope of the RIT 10 ground qualification work, an ion beam diagnostic device has been designed and built up to determine the mechanical beam parameters. Moreover, a small test stand has been designed that allows full thruster operation in order to measure the radiated electromagnetic spectrum in an anechoic test chamber. Besides, the development and tests of a scaled-up 50 mN engine RIT 15 have been continued successfully with xenon, krypton, and also argon as propellants. The ion beam profiles have been measured and the influence of the accel-decel ratio on the beam divergence has been studied. A large ion engine with 35 cm ionizer diameter, the RIT 35, has been developed for primary propulsion aiming at a thrust level in the 250 mN range. A laboratory prototype has been subjected to extensive testing and performance mapping. This preliminary work has been finished waiting for further programmatic decisions.