Multiscale Numerical Simulations of Plasma Charging Effects for Astronaut at the Lunar Terminator

We present four correlated simulation studies concerning plasma charging and its effects over ten orders of magnitude in length scales for astronaut on extravehicular activity (EVA) at the lunar terminator. We carry out particle-in-cell (PIC) simulations to model macroscopic astronaut charging and microscopic dusty spacesuit surface charging, PIC with direct simulation Monte Carlo (DSMC) to model arc discharge onset on dusty spacesuit surface, and atomic-scale molecular dynamics (MD) simulations to model surface charging-induced dielectric material breakdown. We find that the combination of plasma charging and dust adhesion on spacesuit surface can generate a microscopic electric field spacesuit surface on the order of 107 V/m even under moderate global charging conditions. Such electric field may trigger arc discharge, if spacesuit outgassing or leak provides a sufficient neutral environment around astronaut, and may cause direct damage to spacesuit material via dielectric breakdown.