Arcjet plume ionization effects on exposed solar array conducting surfaces

Abstract

High efficiency arcjet propulsion will be used in the near future for satellite orbit adjustment and eventually for orbit transfer. Testing is currently being conducted to explore spacecraft interface difficulties with this method of propulsion. This thesis looks at one aspect of this interface. Since most earth orbiting spacecraft use solar arrays for power generation, it is of interest to investigate how exposed, biased conducting surfaces will interact with the slightly ionized plume environment of the arcjet thruster. It was found that with the arcjet thruster mounted 25.4 cm above the solar array, firing along its axis at a 20 degree cant angle, electrical currents were indeed collected. The effect of having a constricted area exposed to the plume was to increase the current density. The electron densities at typical solar array distances were found to be 10 to the 10th to 10 to the 12th power/cu.m. An estimate of the total power lost for an array in this configuration showed that 0.05% of the overall power is lost due to collected currents.