ATS-6 Cesium Bombardment Engine North-South Stationkeeping Experiment

Two 0.004 N thrust cesium bombardment ion thrusters have been developed and integrated on Applications Technology Satellite-6 (ATS-6) to demonstrate compatible north-south stationkeeping of a geostationary satellite. In addition to the two flight units, an identical system is undergoing extended testing on the ground to demonstrate operating lifetime. Preliminary operation of the two thrusters on ATS-6 was begun on July 17, 1974, and on October 19, 1974. Completely successful operation was achieved on the first run of each. In addition to verifying operation, the principal accomplishments were the demonstration of a total absence of interference with the communications systems, verification of the predicted spacecraft operating potential, demonstration of compatibility with the star tracker, demonstration of spacecraft attitude control by thrust vectoring, measurement of the rate of production of charge exchange ions and of the ability of biased surfaces to repel the ions. Subsequent attempts to operate the thrusters have not been successful. Analysis indicates that the problem is associated with operation of the propellant reservoirs in zero g. Thruster cleanup operations are continuing in parallel with development of solutions to the feed system problem.