High voltage breakdown across insulator surfaces in the space environment

Research in the design of high voltage insulation for the space environment is currently underway at Maxwell's Space Simulation Facility. The voltage standoff capability across insulator surfaces has been shown to deteriorate when exposed to a low density, low temperature plasma for both positive and negative bias. Two techniques to enhance the breakdown strength have been tested, yielding remarkably good results. For negative voltages, the time to breakdown may be extended several orders of magnitude. The results generally agree with calculations based on the assumption that plasma ion currents are responsible for flashover.