• Incorporated geometrically realistic GEO spacecraft configurations with metallic bodies and dielectric-coated surfaces. • A capacitance-coupled model is developed using Method of Moments to simulate differential charging of GEO satellites under Maxwellian plasma environments. • Extended differential charging analysis to account for aging of Aluminum—the ubiquitous spacecraft material—by incorporating varying degrees of oxidation and carbon contamination to realistically represent in-orbit surface conditions. • Demonstrated that material aging critically reshapes differential charging risk, even under identical plasma conditions. • By resolving differential charging dynamics, the study establishes a physics-based pathway to quantify ESD occurrence over mission-relevant time horizons. Estimation of the time scale of differential charging between adjacent metal–dielectric surfaces on a Geosynchronous Earth Orbit (GEO) satellite is crucial due to its potential to trigger Electrostatic Discharge (ESD) events. Since the capacitance between spacecraft surfaces strongly influences the dynamics of differential charging, this work investigates the transient variation of spacecraft body potential by developing a capacitance-based circuit model. The spacecraft is represented by a simplified geometric structure consisting of a metallic cuboid with two co-planar metallic plates, while a thin dielectric layer placed over the plates is used to emulate the cover glass of a solar array. The coupling capacitance between the metallic cuboid and the dielectric layer is evaluated using a Method of Moments (MoM) formulation derived from the electrostatic boundary conditions on conductor and dielectric interfaces. Using the computed capacitance values, the temporal evolution of the spacecraft body potential is analyzed under Maxwellian plasma environments representative of GEO conditions. The study further investigates the influence of induced electron emission processes on the enhancement of differential charging between the solar array cover glass and the spacecraft body. To capture realistic operational conditions, the spacecraft material is modeled as aluminium (Al) in two representative surface states: oxidized Al corresponding to the Beginning of Life (BOL) condition and Al with a thin carbon-rich contamination layer representing the End of Life (EOL) condition. The analysis provides insight into how surface conditions, secondary electron emission characteristics, and electrostatic coupling between dielectric and conducting surfaces affect the magnitude and time scale of differential charging, thereby contributing to improved prediction of ESD risks for spacecraft operating in GEO plasma environments.
Pandya et al. (Wed,) studied this question.