Psyche Reaction Wheel Model Correlation with Near-Zero Speed Flight Data

Psyche is a Discovery spacecraft traveling to the metal-rich (16) Psyche asteroid located approximately 3 AU from the sun. The spacecraft guidance, navigation, and control (GNC) system uses four reaction wheels as the primary actuators to provide precision pointing and slewing capabilities. This paper presents in detail the models that simulate these reaction wheels as part of the GNC simulation used for the verification and validation of GNC algorithms and for making predictions of in-flight behavior. Additionally, this paper describes the model-data correlation process used to modify the simulation based on a comparison of the simulation outputs to flight data acquired during the spacecraft’s initial checkout period. A specific reaction-wheel-induced behavior on spacecraft pointing errors that occurs at low wheel speeds is also presented as the example case for conducting the model-data correlation process.