Fault arc propagation on cables for space applications in vacuum, oxygen-enriched air and air

Investigations of fault are propagation on spacecraft cables under specific conditions, e.g. vacuum, normal and oxygen enriched atmospheres have been performed. Typical patterns of fault arc extinction have been identified and their consequences with respect to causes of damages are discussed. The results indicate that for a given test current and test voltage the behavior of the arc and the damages caused in a cable bundle depend strongly on the kind of insulation material, cable size and design, as well as on the environmental conditions. For some cables the arc propagation effects are increased at higher oxygen partial pressure and significantly increased under vacuum. In many cases vacuum has turned out to be an important worst-case parameter. It was found that the amount of damage assessed by post-test measurements increases substantially, if the value of the test current grows. More than 250 tests have been performed for test currents in the range of 6 to 30 A at the test voltage of 125 V dc