Low Earth Orbit Space Plasma High Voltage System Interactions

Abstract

Space power systems interact with the low Earth orbit (LEO) space plasma in two different ways. One way is the steady collection of current from the plasma onto exposed conductors. The relative currents collected by different parts of the system will determine the floating potential of the spacecraft. Also, steady state collected currents may lead to sputtering or heating of the system by ions or electrons, respectively. The second type of interaction is a short timescale arc into the space plasma, which may deplete the spacecraft of stored charge, damage surfaces, and produce EMI. Such arcs occur at high negative potentials relative to the space plasma potential, and depend on the steady state ion currents. New high voltage power systems incorporated into advanced spacecraft and space platforms may be endangered by these plasma interactions. Recent advances in laboratory testing and current collection modeling promise the capability of controlling, and perhaps even using, space plasma interactions to enable design of reliable high voltage space power systems.