Environment-Induced Electrostatic Discharges as the Cause of Voyager 1 Power-On Resets

The Pioneer and Voyager spacecraft all experienced anomalous behavior during their encounters with Jupiter. In particular, the Voyager 1 spacecraft experienced 42 electrical upsets in the electrical circuitry designed to protect the on-board computer from power fluctuations. Given the diversity of instrumentati on and frequency of the anomalies observed by Voyager 1 in the inner magnetosphere of Jupiter, this set of data is particularly well suited as a case study. Although the nature of the anomalies clearly indicates a spacecraft-charging origin, the Voyager low-energy plasma data apparently imply absolute surface potentials of only a few tens of volts. It is thus difficult to explain the anomalies in terms of surface charging. The anomalies are, however, shown to be consistent with the hypothesis of internal charging of spacecraft parts and components. Nomenclature EMI = electromagnetic interference ERT = Earth-received time ESD = electrostatic discharge FDS - flight data subsystem HGA = high-gain antenna IESD = internal electrostatic discharge LECP = low-energy charge particles LGA = low-gain antenna PLS = plasma science POR = power-on reset PPS = photopolarimeter PRA = planetary radio astronomy PWS = plasma wave subsystem Rj = Jupiter radius RTG = radioisotope thermoelectric generator