The unmanned SpaceX Falcon 9 rocket exploded two minutes after launch, when its two stages were expected to separate. This is the first time in 19 launches that ended in failure, as the 63-meter rocket was able to complete six cargo trips to the ISS and has a 15-flight contract with NASA.
Falcon 9 experienced a problem shortly before first stage shutdown. Will provide more info as soon as we review the data.- Elon Musk (@elonmusk) June 28, 2015
Musk offered a second statement: "There was an overpressure event in the upper stage liquid oxygen tank. Data suggests counterintuitive cause. That's all we can say with confidence right now. Will have more to say following a thorough fault tree analysis."