Hollow cathode emission and ignition characterization

The Hollow Cathode Assembly is a thermionic source of electrons critical to the operation of L-3 Communications, Electron Technologies Incorporated (L-3 ETI) Xenon Ion Propulsion System (XIPScopy) thrusters. There are two cathode subsystems on a XIPScopy thruster: the discharge cathode provides the current for the main discharge and the neutralizer cathode produces an electron stream that prevents the spacecraft from charging as it expels the positive beam ions. The 25 cm XIPScopy serves both orbit-raising and station-keeping functions on the Boeing 702 communication satellite. For stationkeeping the thruster is ignited daily and operated for approximately 1 hour. The ignition of the thruster is preceded by the ignition of both the discharge and neutralizer cathodes. An understanding of the cathode ignition processes is essential to ensure performance of the thruster over itspsila mission life.