Surface Charging Analysis of GSAT-19 Using NASCAP

Abstract

A Spacecraft-Charging Effects Protection Plan is implemented to evaluate the impact of spacecraft-charging-related effects on a spacecraft. The plan involves defining the properties of the natural space plasma to which the spacecraft will be exposed, developing design guidelines with the purpose of reducing or eliminating the effects attributed to spacecraft charging, and performing computer analyses to model the charging level of the spacecraft and determine how spacecraft charging can adversely affect the spacecraft. The analysis is carried out using NASCAP (NASA’s Spacecraft Surface Charging Program). Calculation of absolute potential buildup is carried out and differential potential buildup is derived. Due to the differential voltage developed on different material surfaces of spacecraft in differently illuminated conditions, electrostatic discharge can occur. This ESD can cause arcing, flashover discharge, the coupling of ESD onto the desired signal and punch through of surface. On the basis of the analysis, design recommendations are made to address spacecraft-charging issues that arise.