Sensitivity of rarefied gas simulations of ground tests to gas surface models

Abstract

The space environment produces a number of performance challenges to satellite and spacecraft manufacturers that require measurements, including effects from hyperthermal atomic oxygen, charged particles, magnetic fields, spacecraft charging, ultraviolet radiation, micrometeoroids, and cryogenic temperatures. Ground tests involving a simulated space environment help explore these challenges, but also benefit from simulations that predict the anticipated physical phenomna, or help reconcile the measured observations to physical parameters. We present an update and application of a flexible multi-physics software simulation framework intended for predicting space environment performance and ground-test simulations of spacecraft. In this specific application we show how the energy dependent erosion yield may be applied with a rarefied gas dynamics simluation to aid comparison of terrestrial erosion rate measurements and on-orbit materials degradation. For the considered fluoropolymer material, we found that explcit consideration of the atomic oxygen energy distribution could potentially modify the expected correspondence between ground tests and space by 67%.