Posted: Sat, Oct 31, 2015, 11:18 AM ET (1518 GMT)
A NASA investigation into last year's Antares launch failure could not find a single technical root cause for the accident, saying instead that any combination of three factors could have destroyed the vehicle. The investigation, an executive summary of which was released Thursday, concluded a fire broke out in the liquid oxygen turbopump of one of the rocket's two first stage engines shortly after liftoff, a fire created when parts of the turbopump came into contact with each other. However, the investigation could not find a single root cause for that to take place, saying instead that design issues with the engine, a manufacturing defect, or foreign object debris could have, individually or in combination with each other, caused the accident. A separate Orbital ATK investigation into the failure concluded that a manufacturing defect was the most likely technical root cause, downplaying design issues or foreign object debris. Orbital is no longer using the AJ-26 engine that suffered the failure, switching instead to the RD-181 engine, with a return to flight planned in spring 2016.
