Diagnostic of Neutralization Current for Arcs on Satellite Solar Panel Coupons

Risk of arcing in space plasma environment on satellite solar panel has always been an issue of major concern in the aerospace community. The outcome of round robin tests performed in various laboratories has resulted in finalization of the guidelines for the ground test of satellite solar panel coupons (SSPCs). This is documented as ISO-11221 standards. Authenticity of arc plasma flashover (FO) parameters are still under debate. Some experimental findings that support the perimeter theory of arc FO on geostationary (GEO) satellites are discussed in this paper. It has been observed that characteristics of an the arc are dependent on its location on the solar coupon, bias charge (charge due to bias voltage and external capacitance), and the total charge dissipated during the arc discharge. It is also observed that the duration between the two consecutive arcs is directly proportional to the dissipated charge or energy of the latter arc. A combined dielectric consisting of solar cell, adhesive, Kapton, and Carbon Fiber Reinforced Polymer sheet holds charge during irradiation by the electron gun. This resembles surface FO capacitance. Arc energy is governed by the combined effects of a surface flashover capacitor (C-sf) and an external capacitor. It is observed that if intermittent arc duration is sufficiently longer than the gradual accumulation of charge on the SSPC, body may lead to a major arc. This would increase the probability of secondary arcs when the sustained arc environment is experienced by the satellite. To understand primary arcs on dielectrics, an artificial triple junction is prepared and exposed under adverse GEO-like space conditions. Various signatures identified from the arc current and arc neutralization current waveforms specify the behavior of these arcs at different locations on the coupon surface. In this paper, current waveforms of arcs captured on different types of solar panel coupons and their significance are studied. Information about arc energy, arc velocity, and neutralization velocity are extracted from the measured waveforms.