Anomalous Global Positioning System Power Degradation from Arc-Induced Contamination

Abstract

It is well known that many GPS satellites have experienced power degradation in excess of what would be expected from radiation damage on their solar arrays. Originally, contamination was suspected, based on the time behavior and rate of degradation seen. Calorimeters were included on some satellites, and a temperature rise commensurate with the power loss was detected, but subsequent efforts to eliminate line-of-sight paths from the contamination sources were unfruitful in reducing the power degradation. The hypothesis put forward here is that the contamination is the result of solar array arcing over a GPS lifetime. In this paper, we examine this hypothesis, using known characteristics of space solar array arcs, to place limits on the arc rate that would be sufficient to produce the contamination-induced power losses seen on GPS satellites to date. Comparisons with United States Nuclear Detonation Detection System signals on GPS satellites are consistent with at least some of the United States Nuclear Detonation Detection System events being solar array arcs. If the hypothesis can be confirmed, simple measures to prevent arcing on GPS arrays can lower the contamination rate and either increase end-of-life power or allow reduced beginning-of-life power.