SpaceX Accident Investigation Team Narrows Cause of Falcon 9 Firexplanomaly


SpaceX Update
October 28, 4:00 pm EDT

The Accident Investigation Team continues to make progress in examining the anomaly on September 1 that led to the loss of a Falcon 9 and its payload at Launch Complex 40 (LC-40), Cape Canaveral Air Force Station, Florida.

Since the incident, investigators from SpaceX, the FAA, NASA, the US Air Force and industry experts have been working methodically through an extensive fault tree to investigate all plausible causes. As part of this, we have conducted tests at our facility in McGregor, Texas, attempting to replicate as closely as possible the conditions that may have led to the mishap.

The investigation team has made significant progress on the fault tree. Previously, we announced the investigation was focusing on a breach in the cryogenic helium system of the second stage liquid oxygen tank. The root cause of the breach has not yet been confirmed, but attention has continued to narrow to one of the three composite overwrapped pressure vessels (COPVs) inside the LOX tank. Through extensive testing in Texas, SpaceX has shown that it can re-create a COPV failure entirely through helium loading conditions. These conditions are mainly affected by the temperature and pressure of the helium being loaded.

SpaceX’s efforts are now focused on two areas – finding the exact root cause, and developing improved helium loading conditions that allow SpaceX to reliably load Falcon 9. With the advanced state of the investigation, we also plan to resume stage testing in Texas in the coming days, while continuing to focus on completion of the investigation. This is an important milestone on the path to returning to flight.

Pending the results of the investigation, we continue to work towards returning to flight before the end of the year. Our launch sites at Kennedy Space Center, Florida, and Vandenberg Air Force Base, California, remain on track to be operational in this timeframe.


  • JamesG

    I’m sure they are looking very hard at titanium alloys…

  • Hug Doug

    Depends on the part; if they can source it for cheaper than they can build it in-house, or if building it in-house requires expertise that SpaceX doesn’t need to build up internally, they’ll buy it from a supplier. From personal experience, the company I work for builds circuit boards that are used by SpaceX. I know their parachutes are made by Airborne Systems, and I’m sure there’s lots more.

  • Rocketplumber

    We had hot bottles at XCOR back in 2007, so I (probably re-) invented the technique of running the helium through a coil immersed in LN2 immediately before the fill port on the vehicle. That’s how we demonstrated <9 minute fill of the X-Racer with LOX, kerosene, and helium in 2008. I've long preached the virtues of interlocked ignition and cascaded purges (taught to me by Del Tischler and Jerry Cuffe), but never thought anyone doing speed load of helium wouldn't reinvent it themselves.