Abstract
An MPD (Magnetoplasmadynamic) arcjet system was assembled as a quarter-scale model of 1 kW thruster system dedicated to 3-million-shot endurance verification and to ground verifications such as mechanical, thermal and other environmental interface tests. It was installed on the SFU (Space Flyer Unit) launched on March 18, 1995 and tested as EPEX (Electric Propulsion Experiment) in space. All the system functioned properly and successfully demonstrated its propulsive function with hydrazine propellant. The system accumulated on/off cycles in space reached 43,395 pulses with misfirings of only 0.3 % during the several-day of assigned experiment period. The electrical power unit consisting of a single-staged capacitor bank was driven by the solar array. The generated thrust measured in space and the idealized specific impulse corresponding to 1,000 sec capability for full 1 kW system were also estimated to be the same as those obtained in the ground test.
