Graphite Orificed Hollow Cathodes for Xenon Ion Thrusters

[Abstract] Two sizes of graphite orificed hollow ca thodes are described: one is for the main cathode of a 150-mN ion thruster and the other is for its neutralizer. One of the main cathodes is running to fail using a discharge chamb er, with which the discharge voltage, discharge current and propellant flow rate for the cathode can be simultaneously the same as those of a real thruster in nominal operation. T he cumulative operation time has reached 9,000 h and no signs of performance degradation have ever been found so far. Neutralizers have been operated as a component of a thruster and evaluated by coupling voltages, which have been kept low enough. Graphite orifice plates have shown high resistance to wear.