Spacecraft Charging, Plume Interactions, and Space Radiation Design Considerations for All-Electric GEO Satellite Missions

The use of electric propulsion (EP) for geostationary Earth orbit (GEO) stationkeeping and geostationary transfer orbit offers satellite operators the opportunity to reduce mission costs and to increase revenue by enabling a higher dry mass to orbit compared with traditional chemical or EP systems. The penalty for such benefits comes, initially, in the form of an increased time-to-orbit whereby the low-thrust transfer orbit duration will range from a few months, at best, to possibly one year or more. During the low-thrust transfer, the spacecraft will experience prolonged exposure to the portions of the trapped radiation belts to which the GEO spacecraft otherwise would not be subjected—most notably the inner belt and slot region. Further, the spacecraft will also experience on the order of $10^{5}$ h of high-density high-energy plume plasma—a more challenging operational environment compared with that typically applied to the GEO spacecraft. Applicable environments are introduced, an overview of specific operational effects is provided, and design guidelines are highlighted.