A direct-measurement technique for estimating discharge-chamber lifetimeThe use of short-term measurement techniques for predicting the wearout of ion thrusters resulting from sputter-erosion damage is investigated. The laminar-thin-film technique is found to provide high precision erosion-rate data, although the erosion rates are generally substantially higher than those found during long-term erosion tests, so that the results must be interpreted in a relative sense. A technique for obtaining absolute measurements is developed using a masked-substrate arrangement. This new technique provides a means for estimating the lifetimes of critical discharge-chamber components based on direct measurements of sputter-erosion depths obtained during short-duration (approximately 1 hr) tests. Results obtained using the direct-measurement technique are shown to agree with sputter-erosion depths calculated for the plasma conditions of the test. The direct-measurement approach is found to be applicable to both mercury and argon discharge-plasma environments and will be useful for estimating the lifetimes of inert gas and extended performance mercury ion thrusters currently under development.
Beattie, J. R. (Hughes Research Labs. Malibu, CA, United States)
Garvin, H. L. (Hughes Research Laboratories Malibu, CA, United States)
August 11, 2013
November 1, 1982
Spacecraft Propulsion And Power
AIAA PAPER 82-1908
Meeting: Japan Society for Aeronautical and Space Sciences, and DGLR, International Electric Propulsion Conference