SpaceX and NASA Still Determining Reasons for Falcon 9 Engine Failure, Other Anomalies
Speaking to the NASA Advisory Council's Human Exploration and Operations Committee today, ISS program manager Mike Suffredini said that Space X is still trying to determine what happened to the engine. NASA is participating in the investigation, he said, and a fault tree analysis is underway.
Several other problems also arose during the mission. While berthed to the ISS, one of the three computers on the Dragon spacecraft failed. Dragon can operate with only two computers, and SpaceX chose to proceed with the two functioning units rather than trying to fix the faulty unit while on orbit. According to Suffredini's charts, Flight Computer-B "de-synched" from the other two "due to a suspected radiation hit" and although it was rebooted successfully, it was "not resynched." Dragon experienced other anomalies because of radiation as well. One of three GPS units, the Propulsion and Trunk computers and Ethernet switch all experienced "suspected radiation hits," but all were recovered after a power cycle. Suffredini said that SpaceX is considering whether it needs to use radiation-hardened parts instead, but noted that "rad-hardened" computers, for example, not only are more expensive, but slower. He speculated that the company would ultimately decide to use rad-hardened components in the future unless it is cost-prohibitive.