Relationship between electrostatic discharges on spacecraft P78-2 and the electron environment

Pulses detected by the P78-2 spacecraft charging at high altitudes (SCATHA) pulse analyzer are divisible into two groups: those from surface charges, which occurred when the test samples on the vehicle surface were charged relative to the vehicle frame, and those from internal discharges, which occurred when the test samples on the surface were not charged. SCATHA data have confirmed all aspects of the spacecraft charging hypotheses first postulated as a basis for satellite anomalies in the mid-1970s; the connections among the energetic electron environment, the surface and internal charging of vehicle materials, electrostatic discharges, and spacecraft anomalies, have been verified. (O.C.)