Electrical Discharges at Altitudes between 70,000 and 250,000 Feet

Experimental measurements of electrical discharges caused by corona, glow discharges, and voltage breakdown were made under conditions encountered in aerospace vehicles operating within the 70,000 to 250,000 foot altitude range. All measurements were made in gases commonly used to pressurize spacecraft electrical and electronic compartments: nitrogen, nitrogenoxygen mixtures, and normal atmosphere at sea-level pressure. Test results show that: (1) the onset voltage at which the electrical discharge occurred is much lower for spaced wires than for bundled or twisted wires; (2) the onset voltage between wires increases as the insulation thickness and dielectric constant are increased and decreases as the wire diameter and wire spacing are increased; and (3) that the onset voltage of components depends on the type of component and its connection and installation.