Back in early September, one of SpaceX‘s Falcon 9 rockets abruptly exploded during a routine filling operation, and it left the space agency confused by the mystery, with founder Elon Musk calling it their “most difficult and complex failure” they’ve ever experienced. Well, it seems a cause has finally been identified, with investigations completed and Musk stating that it was a “surprising problem that’s never been encountered before in the history of rocketry.”
Speaking to CNBC on Friday, Musk explained that “it basically involves liquid helium, advanced carbon fiber composites, and solid oxygen. Oxygen so cold that it actually enters solid phase.” It’s suggested that this oxygen froze solid as it passed through the rocket’s second stage, then caused an explosive reaction when it reached one of three carbon fiber helium tanks that are placed within the main fuel tank.
SpaceX didn’t reveal too many additional details, including exactly what caused the oxygen to turn into a solid and how it affected the helium tanks, but the agency says its engineers were able to replicate the ruptured helium tank.
Despite this lengthy setback, SpaceX says it now believes it will be able to resume Falcon 9 launches before the end of December. Thanks to getting to the bottom of the explosion mystery, they will continue to analyze and improve their process for loading helium, in turn preventing a repeat of this accident.