Strut likely culprit in SpaceX rocket explosion

It was a routine mission that quickly ended in disaster.

Three weeks ago, a SpaceX attempt to resupply the International Space Station failed well before reaching its mark.

According to SpaceX's founder, Elon Musk, the company has more or less reached a verdict on the cause of last month's crash.

On a conference call with reporters, Musk said his engineers had made an "initial assessment" that attributed the crash to a faulty strut—a piece of steel two feet long and one inch wide—which gave way well below its designed and certified capacity of 10,000 pounds.

During launch, the struts only need to withstand 3,500 pounds of force, but an internal audit by SpaceX found that many of the struts—acquired from an unnamed third-party vendor—had failed at around 2,000 pounds.

Once the strut failed, the Falcon 9 rocket was doomed by a quick chain reaction: a helium tank broke free inside the oxygen tank causing the helium to leak into the oxygen tank at uncontrolled rate, which in turn caused "an overpressure event."

"It's a really odd failure mode," Musk said to reporters.

No one was harmed during the crash, but all 4,000 pounds of cargo intended for the space station were destroyed and SpaceX has been sent back to the drawing board once again.

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