Discharge over spacecraft insulator surface in low Earth orbit plasma environment

When a spacecraft operates at HV, the spacecraft body potential becomes highly negative with respect to the surrounding plasma. A laboratory experiment has been carried out to study the interaction between the spacecraft insulator surface and the plasma. Once a discharge occurs through the insulator at one point on the surface, the positive current to the circuit drives the conductor, which lies below the insulator, positive. The potential of the undischarged surface increases as the conductor potential increases and collects electrons by neutralizing the positive charge stored before the discharge. The current path of an RC discharge is formed between the discharge spot and the undischarged insulator surface, which acts as the capacitance, through the plasma resistance and the spacecraft circuit resistance. An ion acoustic wave, launched by the potential jump of the undischarged surface, was detected by a Langmuir probe. There is a possibility that a very large amount of current flows into the spacecraft body circuit because the capacitance of the entire spacecraft surface is large.