ETS-III ion engine flight operations in the extended mission period

Abstract

An ion engine subsystem with two electron bombardment mercury ion thrusters of 5 cm anode diameter was flight tested on the Engineering Test Satellite-Ill during an extended mission from September 1983 to March 1985. Three tests were conducted: on/off cyclic tests for the both thrusters, continuous beam test for thruster 1, and continuous discharge test for thruster 2. The flight data were compared with that from the main mission (September 1982 to August 1983). With total operating hours and restarts of 66 h/47 cycles for the neutralize^ 64 h/53 cycles for the discharge, and 53 h/45 cycles for the beam on thruster 1 and 239 h/180 cycles for the neutralize!-, 356 h/188 cycles for the discharge, and 220 h/172 cycles for the beam on thruster 2, the ion production and extraction were found normal and unchanged. The hollow cathodes were found to be activated by repeating their operations. The operation of the entire spacecraft was ended with the depletion of the hydrazine used in the reaction control subsystem.