A steel strut holding a helium bottle inside a SpaceX Falcon 9 rocket snapped during flight, setting off a chain reaction that destroyed the rocket during a June launch, the company’s CEO and chief rocket-designer Elon Musk said.
“One of those struts failed and was unable to hold the helium bottle down, and the helium bottle would have shot to the top of the tank at high speed,” Musk said in a call with reporters today, characterizing his analysis as an “initial assessment” that is highly probable but not definitive.
Fixing the problem will delay the SpaceX’s launch schedule by at least a month, with no new flights until at least September. The company had previously scheduled its next flight in early August. Musk says the delays will mean hundreds of millions of dollars in lost revenue.
The helium bottles are stored within the liquid-oxygen fuel tank to sustain pressure as the fuel is consumed during flight. Pre-flight tests apparently missed the flaw in the strut because the stress increases at higher g-force pressure. Musk said that after the crash, SpaceX tested thousands of struts from the supplier that made them, and discovered several that failed below their rated tolerances.
“Obviously, what we’re going to do in the future is not use these particular struts, and we’re going to move to individually testing each strut independent of any material certifications,” Musk said. “There will be some cost increase to the rocket, and not we believe to a significant amount.”