Modelling atomic oxygen erosion-induced surface roughening and its impact on drag evolution for Very Low Earth Orbit (vleo) satellites

Abstract

Very-Low Earth Orbit (VLEO) platforms operate in a regime where high aerodynamic drag and atomic-oxygen (AO) erosion critically constrain mission lifetime. Accurate prediction of these effects requires gas-surface interaction (GSI) models that evolve with surface morphology rather than relying on constant accommodation coefficients. We present a multi-scale erosion-aerodynamics framework that links molecular dynamics (MD) simulations of hyperthermal AO scattering to surrogate Cercignani-Lampis-Lord (CLL) kernels, which are mapped across surface micro facets to account for roughness growth. These time-dependent parameters drive Direct Simulation Monte Carlo (DSMC) analyses that resolve aerodynamic forces and AO flux distributions. An erosion update law then modifies surface roughness and closes the loop, while the resulting drag coefficients are propagated in orbit dynamics for estimating drag coefficient state. The framework enables physically consistent, time-resolved drag prediction, supporting VLEO satellite design, drag compensation strategies, and mission lifetime assessment under realistic AO exposure.