scope:

Abstract:

NSI firing circuit design has not previously taken into account the high probability of plasma shorts and subsequent hard-shorting, as seen during testing on MER, which allowed ground (chassis) return current during pyrotechnic events. Mars Exploration Rover experience has shown that molten NSI fragments can cause a prolonged NSI pin-to-case short that can damage flight hardware. Thirteen design, analysis, inspection, and test recommendations in the areas of Parts Selection and Reliability Analysis, Power/Pyro Design, and System Grounding are offered to account for this possibility.