The Effect of Reaction Control System Thruster Plume Impingement on Orion Service Module Solar Array Power Production

NASA’s new Orion Crew Exploration Vehicle has geometry that orients the reaction control system (RCS) thrusters such that they can impinge upon the surface of Orion’s solar array wings (SAWs). Plume impingement can cause Paschen discharge, chemical contamination, thermal loading, erosion, and force loading on the SAW surface, especially when the SAWs are in a worst-case orientation (pointed 45° towards the aft end of the vehicle). Preliminary plume impingement assessment methods were needed to determine whether in-depth, time-consuming calculations were required to assess power loss. Simple methods for assessing power loss as a result of these anomalies were developed to determine whether plume impingement induced power losses were below the assumed contamination loss budget of 2%. This paper details the methods that were developed and applies them to Orion’s worst-case orientation. Nomenclature λ = wavelength of incident light τ = contaminant mass per unit area T = transmittance