INTEGRATED TEST OF AN SPT-100 SUBSYSTEM

An integrated test of a stationary plasma thruster (SPT) subsystem, used for geostationary spacecraft north/south station keeping (NSSK), has been completed by International Space Technology Inc. (ISTI). This subsystem consisted of the following components: the qualification unit SPT-100 thruster provided by Fakel, the two qualification unit xenon flow controllers (XFC's) provided by Fakel, the qualification unit power processing unit (PPU) provided by Space Systems/Loral (SS/L), the protoflight half-system propellant management assembly (PMA) provided by Moog, and the flight type xenon propellant tank provided by Lincoln Composites. The test was performed over a large range of input parameters expected to be seen over the course of a flight mission. Such input parameter variations included varying the PMA inlet pressure from 6 to 150 bar and varying the thruster input power from 1200 W to 1500 W. Most of the test was performed at the nominal 4.5 A (1350 W) thruster input conditions where average thruster performance exceeded 80 mN thrust and 1500 s specific impulse. The total test duration was 712 firing cycles and 1003 hours of thruster operation.