PPPS-2013: Measurement of ESD plasma propagation on a postively charged ISS solar array coupon

Summary form only given. It is well known that dielectric surfaces such as those on solar arrays are susceptible to surface charging in the space environment. If the charging is sufficient, a spontaneous arc can occur, triggering an outward-propagating electrostatic discharge plasma. The propagation speed and the fraction of charge cleared by this so-called “brush-fire” plasma, determines the amplitude of potentially damage-inducing current transients on the solar array strings. Numerous ground tests have been performed to determine an appropriate propagation speed, giving a wide range of results. Each study used a slightly different methodology and a completely different test article. To address this inconsistency, a US-wide Round Robin Test Campaign was initiated by AFRL to determine propagation dynamics on a series of shared test articles using common test methodology across multiple labs.
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In this paper, we report on tests performed with the first test article in this series, an ISS-inspired solar array coupon. We induced a positive potential on insulator surfaces via electron beam impingement on the biased coupon, and captured current transients on the solar array strings using current probes on a set of synchronized oscilloscopes. A non-contact, scanning electrostatic probe was used to measure surface potentials and a high speed camera was employed to pinpoint the origin of each discharge event. Interpretation and discussion of our results will be presented.