scope:

Abstract:

The "most probable cause" of the Mars Observer mission failure was identified as migration of substantial amounts of nitrogen tetroxide oxidizer upstream through the check valves where it condensed on the cold tubing. When the pressurization sequence was executed upon Mars encounter, the liquid oxidizer may have mixed rapidly with fuel in the lines and detonated. The recommendations included (1) preventing hazardous propellant vapor migration and (2) performing thermal analysis of pressurization systems to identify incipient conditions for propellant condensation.