Spacecraft charging, an update

Summary form only given. Nearly twenty years after the landmark SCATHA program, spacecraft charging and its associated plasma interactions continue to be major issues for Earth-orbiting spacecraft. Although typically thought of as a surface effect on geosynchronous spacecraft, internal charging and low-altitude phenomena are increasingly causing concern. Since the time of SCATHA, spacecraft charging investigation efforts were focused on surface effects and spacecraft design issues. Today a growing proportion of spacecraft anomalies are believed to be caused by internal charging effects (charging and ESD events inside the spacecraft Faraday cage). This review, following a brief summary of the state of the art in surface charging, concentrates on the problems introduced by penetrating electrons ("internal charging") and related processes (buried charge and deep dielectric charging) and on the issues tied to the dense, low altitude plasma environment and the auroral zone. Likewise, with the advent of tethered spacecraft and the deployment of the International Space Station (shortly), low altitude charging has taken on a new significance and urgency.