Project COMPASS-POINT
Introduction
COMPASS POINT is a joint project between the Electric Propulsion and Plasma Dynamics Lab (EPPDyL) of Princeton University and the Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation of the Russian Academy of Science (IZMIRAN) to carry in-orbit investigations with an ablative pulsed plasma thruster onboard COMPASS, an IZMIRAN scientific microsatellite to be launched in October, 1996 using the Shtyl-2 launcher from a Russian submarine. The unmodified LES 8/9 APPT module produces impulse bits of 285 microN-s at an Isp of 836 s using 25 W of power on average. The APPT module will be used to conduct in-orbit investigations of pulsed plasma propulsion as well as to provide attitude control of the satellite and a source of plasma for active space experiments. Details of the power, command, and telemetry signals required to operate the device on the COMPASS satellite are presented in JPC 1996 paper below. Thermal control and various operational modes are also outlined in that paper. Operational modes include a combination of right and left nozzle pulse sequences for determining the performance and impulse bit of the APPT module in space. Documented pre-flight experiments include a temporary hardware addition that simulates the plasma discharge necessary for the pre-flight atmospheric integration test at IZMIRAN. Also described are the experimental measurements of the thrust efficiency, center of mass, and moments of inertia of the module.