Falcon 9 failed... Dang it! Elon Musk is already tweeting about the cause – an “overpressure event” in the second stage liquid oxygen tank. Commenters were speculating that almost in real time; apparently quite a few observers are familiar with the internal details of the Falcon 9. Probably the biggest consequence to this is that they lost the payload, which included the docking adapter needed by SpaceX's Dragon crew capsule and other competing launch vehicles. Hope they have a spare somewhere!