Simulation framework for space environment ground test fidelity

We present initial work to develop an extensible model for spacecraft environmental interactions. The starting point for model development is a rarefied gas dynamics model for hyperthermal atomic oxygen. The space envi- ronment produces a number of challenging stimuli, including atomic oxygen, but also charged particles, magnetic fields, spacecraft charging, ultraviolet radiation, micrometeoroids, and cryogenic temperatures. Moreover, the responses of spacecraft to combinations or sequences of these stimuli are different from their responses to single stimuli. New multi-stimulus test facilities such as the Space Threat Assessment Testbed at the USAF Arnold Engi- neering Development Complex make understanding the similarities and differences between terrestrial test and on-orbit conditions increasingly relevant. The extensible model framework under development is intended to host the variety of models needed to describe the multiphysics environment, allowing them to interact to produce a consistent unified picture. The model framework will host modules that can be validated individually or in combination.