SpaceX suspects a 2-foot steel strut snapped inside its rocket and led to last month's launch accident at Cape Canaveral, Florida.
The company's founder and chief executive, Elon Musk, said Monday that these struts had flown many times before without any problem. But two minutes into the June 28 launch, one of the struts in the second stage of the unmanned Falcon 9 rocket likely broke loose. The strut was holding down a helium bottle in the liquid oxygen tank.
Musk says if the strut snapped as engineers believe, the helium bottle would have shot to the top of the tank at high speed, dooming the rocket and its Dragon supply ship for the International Space Station.
Musk stressed at a news conference that these are preliminary results.