Electrostatic discharge induced degradation of solar arrays

On-orbit data indicates 2.5%-a-year degradation in solar array power output for spacecraft in half-synchronous orbit. This unexplained degradation is sometimes attributed to contamination. Testing suggests that a large fraction of this degradation may be electrostatic-discharge-induced, and can be eliminated by conductivity coating the solar array coverglass. More long-term testing is required to confirm that degradation will accumulate linearly with time and to determine the dependence of such degradation on electron energy and electron flux density