Ions Generated on or Near Satellite Surfaces

Observations of positively charged particles that are generated on or near satellite surfaces have been made on several spacecraft. This thesis postulates sputtering of the satellite surface due to ambient ion impact as the generating mechanism. Calculations are made using the Sigmund-Thompson sputtering theory to determine the response at the satellite particle detectors. These calculations indicate that surface sputtering creates a sufficient flux to account for the observed phenomena. The NASA Charging Analyzer program was run to determine the trajectories for measured particles. The calculated trajectories were determined to lead to the spacecraft surface, again indicating that surface emission was the source. The sputtering flux as calculated was insufficient to cause any significant short-term damage to the spacecraft, beyond thin coating erosion. Keywords: Sputtering, Ion emission, Theses.