Forty Years of Giessen EP-Activities and the Recent RIT-Microthruster Development

Since the early 60ies, gridded ion thrusters with rf-ionizaton of the propellant (first mercury, lateron xenon) have been designed, built, investigated, optimized, and tested at Giessen University. Since 1970, the industry (now EADS Space Transportation) carried out related D & Q programs. The joint work was at first focused on the 10-cm NSSK engine RIT-10, which was flown onboard "EURECA", lifetime tsted over more than 20,000 hrs, and successfully applied in the "ARTEMIS" rescue mission. Since the 70ies, rf-engines have been scaled up and tested by the Giessen team or by EADS with 15, 20, 22, 26, and 35 cm of ionizer diam. In addition, spin-off engines for material processing and fusion plasma heating have been developed. Moreover, discharge and beam diagnostic work, thruster modelling, and mission analysis have been performed. Recently, the Giessen EP-team is engaged in supporting the EADS-tests of the RIT-22 thruster, in investigating of an insertless rf-electron source, in SEP-mission analysis, and especially in scaling-down the standard RIT-10 engine. For microthrusting applications, 4-cm and 2-cm diam RIT-prototypes are under R & D programs.