SPACECRAFT CHARGING DUE TO POSITIVE-ION EMISSION - EXPERIMENTAL-STUDY

Results have been obtained from the flight of a sounding rocket payload instrumented to determine the cause and extent of charging of vehicles in the ionosphere during the ejection of energetic charged particles. Vehicle potential was measured using several independent probes while beams of positive ions or electrons were ejected. Positive and negative potentials were created by the ejection of electrons and positive ions respectively. For constant ion currents of 8 microamperes and energies of 1 keV, vehicle potentials ranged from volts to hundreds of volts, depending on ambient plasma density but independent of neutral density and vehicle pitch angle. A maximum vehicle potential greater than 1 kV was obtained during the emission of 400 microamperes of 2 keV positive xenon ions. This paper is not subject to U.S. copyright.