High voltages in space: innovation in space insulation

The results of the Space Power Experiment Aboard Rockets (SPEAR) rocket series, which evaluated the effects of the space environment on high voltage (HV) insulation, are described. SPEAR I demonstrated that voltages >40 kV could be sustained in the space environment. SPEAR II ground-based simulations and tests demonstrated a number of new technologies for utilizing the properties of the space environment to reduce insulation requirements. Its results led to the construction of a reliable, lightweight, 6- to 100-kV, 1-MV pulse transformer that had significantly reduced bulk insulating media and solid insulators. A space-vacuum-insulated, lightweight, high-current storage inductor was developed which advanced the state of the art in space insulation. The SPEAR III experiment combined these developments in HV insulation technology into a comprehensive test of methods for grounding high potentials in space.>