Spacecraft Charging Analysis of Large GEO Satellites Using MUSCAT

A series of spacecraft charging analyses was carried out for large GEO satellites using Multi-Utility Spacecraft Charging Analysis Tool. The purpose was to derive the number of electrostatic discharges expected for 15 years in orbit, which would be used as the basis of the number of primary electrostatic discharges (ESDs) to be used in future solar cell coupon ESD tests. The combinations of GEO plasma parameters (electron density, proton density, electron energy, and proton energy) that have a high probability of occurrence have been identified first. For each of those plasma parameters, a charging analysis was done. In the simulation, the time for the differential voltage between solar array cover glass and the spacecraft chassis to reach the ESD inception threshold was calculated. The results indicate that, for a typical GEO satellite, the expected number of ESDs in 15 years is on the order of 10 000, agreeing well with the previous work where another satellite was simulated by NASCAP/GEO.