SpaceX says tank failure caused rocket explosion
Four months after a Falcon 9 rocket exploded on a Florida launch pad, SpaceX said Monday that the cause was a failed composite overwrapped pressure vessel used to store liquid helium.
In the final update to its investigation, the space company said one of three such tanks in the rockets larger, second-stage liquid oxygen tank failed, probably after a buildup of liquid oxygen between the vessels aluminum inner liner and its carbon overwrap ignited.
The company said its accident investigation team comprising officials from SpaceX, NASA, the National Transportation Safety Board, the Air Force, the Federal Aviation Administration and industry experts found buckles, or valleys, in the vessels inner liners.
Super-chilled liquid oxygen can gather in buckles, and when pressurized, the oxygen can get trapped. Then, breaking fibers or friction can ignite the oxygen in the overwrap, causing an explosion, SpaceX said.
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