Arc Mitigation via Solar Panel Grouting and Curing Under Simulated LEO-Like Plasma Environment

Electrostatic discharge is a common phenomenon in satellite solar arrays because of surface charging by low-density space plasma, which may sometimes permanently damage the solar array. Experiments were carried out in two types of solar cell arrays [Si and advanced triple junction (ATJ)] to arrive at arc generation statistics. The experiment was carried out for both grouted and nongrouted panels, and the effect of plasma density variation was also studied. It was observed that arc rate decreases drastically in the first 1.0 h of exposing the coupon to plasma and then it gets saturated. This value remains stable if the panel remains in vacuum and does not get exposed to atmosphere again. In the case of a grouted coupon, initial number of arcs was found to be much less compared with those on ungrouted coupon. In the case of grouted coupon, the arc rate after long curing does not change even after exposing to the atmosphere again, whereas for nongrouted coupon, the arc rate goes to a higher value of the same order as the initial value after exposure to atmosphere. Results show that the gases trapped inside the panel come out during arcing and thus reduce arc initiation. For the grouted coupon, the probability to reabsorb gases is low. The number of arcs is found to increase with increase in plasma density, probably because of panel charging at a faster time scale, and is always found to be higher in the case of ATJ solar cell than Si solar cell.