Abstract This article details the results of a failure analysis performed on a Qualification Unit injector for a military satellite thrusters and explains that the failure was initially detected due to a shift in performance during qualification testing. Failure analysis involved non-destructive evaluation on the injector using micro-focus X-ray and scanning electron microscopy. Serial cross-sectional metallography was then performed, with each cross-section documented by optical microscopy and SEM. The failure analysis resulted in three main conclusions: (1) the root cause of the failure was attributed to multiple detonations in or around the damaged orifice; these detonations were likely caused by fuel and/or combustion products condensing in the orifice between pulses and then igniting during a subsequent pulse; (2) multiple damage mechanisms were identified in addition to the ZOT detonations; and (3) the material and platelet manufacturing process met all design parameters.