Spacecraft Surface Charging & ESD Simulator

A satellite orbits with one face toward the Sun and the other in shadow, immersed in a hot, thin magnetospheric plasma. This simulator integrates the real current-balance equation — thermal electron collection, thermal ion collection, and photoemission — separately for the sunlit and shadowed surfaces, so the two sides drift to genuinely different equilibrium potentials exactly as a real geostationary satellite does during a substorm. Push the plasma into "substorm" conditions (hotter, denser), switch to an uncoated dielectric panel, or fly into Earth's shadow, and watch the differential potential climb — cross the roughly 1 kV arc threshold and the simulator fires a visible electrostatic discharge that punches the two surfaces back toward equilibrium, tallying every arc it triggers.