Experimental Evidence of the Three-Dimensional Flashover Expansion over a Nanosatellite Mockup

The expansion of a flashover plasma around a nanosatellite mockup is characterized in a plasma environment representative of low Earth orbit and auroral crossing conditions, using a high negative voltage generator and a plasma source. Hence, the covering insulators get positively charged with respect to the structure. The discharge currents flowing from the structure to the plasma and to the insulating covers are measured at several points with a floating instrumentation embedded in the mockup following previous work performed under Vacuum Ultra Violet illumination and electron beam. The results presented in this paper show that the flashover spreads over surfaces hidden from the discharge ignition point. These surfaces can increase flashover durations, the quantity of charge, and the energy dissipated at the discharge spot. Discharges with a total flashover charge between 10 and [Formula: see text] have been produced, and the neutralization rate of the surface varies from 12 to 2% (from the closest to the most remote hidden section). Following a test-as-you-fly philosophy, the specification of electrostatic discharge characteristics for small satellites should be executed with mockups, especially when solar panels are fixed on the platform surface. This contrasts especially with geosynchronous telecom spacecraft equipped with very large solar panels.