Laboratory Tests on 110-Volt Solar Arrays in Ion Thruster Plasma Environment

Ground-based experiments on the interaction between solar arrays of the Engineering Test Satellite VIII and ion thruster plasma are carried out. We carry out the experiments with two different designs of the solar arrays,and the results are compared. The electron current collection by the positively biased solar array is reported. The dependence of arcing rates on the bias voltage and the neutral gas density of negatively biased solar array are reported. Failure of the ion thruster neutralizer is simulated, and the sustained arc is observed at the gap between the adjacent cells of the solar array without room temperature vulcanization silicon grouting with the potential difference of 55 V and the current of 2.64 A. The grouting prevents a sustained arc even under the worst condition expected for the satellite. A sustained arc is observed bridging two interconnectors separated by 6 cm with an interstring voltage of 130 V and current of 2.64 A for the array with grouting.