Reduced-order modeling of facility effects on grid erosion and electron backstreaming in ion thrusters

Abstract

We present and analyze results from a gridded ion thruster predictive engineering model (GIT PEM). The GIT PEM integrates coupled models of ion optics, erosion, electron backstreaming, and facility effects, reformulated for fast simulation times, enabling statistically significant ensembles for mission life uncertainty analysis. Validation against the NASA solar technology application readiness thruster long duration and extended life tests demonstrates good agreement with observed trends. Compared to state-of-the-art ion optics codes such as CEX2D, the GIT PEM produces similar results but reduces computational time from hours to seconds, enabling rapid assessment of thruster behavior. By accounting for facility effects in such as charge-exchange erosion and facility-borne deposition in terrestrial vacuum chambers, the model allows extension to in-space operation and erosion processes. Results show that competing facility effects can mask true erosion and backstreaming behavior; if improperly understood, these effects may lead to an incorrect estimation of thruster lifetime.