Model of plasma contactor performance

A hollow cathode-based plasma contactor will be flown on the International Space Station to control the station's potential to within +/- 40 V of the local ionosphere. Extensive testing of the plasma contactor has been conducted in vacuum facilities at NASA /Lewis. Significant performance differences were observed between tests of the same plasma contactor in different facilities. This paper addresses why measured plasma contactor performance differs in the laboratory in different tank environments and how the plasma contactor performance measured in the laboratory relates to expected performance in space. Presented are models of plasma contactor plasma generation and interaction in a laboratory environment, including anode area limiting. These models were integrated using the Space Station Environment Work Bench to predict plasma contactor operation, and the results are compared with the laboratory measurements. (Author)