Yesterday, the Air Force was planning on running a 300-second test of the Waverider X51A, its hypersonic craft that should be capable of speeds in excess of Mach 6.
Instead of 300 seconds, a fault with one of the fins caused the flight to end after 16 seconds when the craft went out of control following its launch from the bottom of a bomber.
The fault occurred before the scramjet fired, so researchers remotely destroyed the craft. Unfortunately, it didn't get a chance to hit its ludicrous top speed.
This comes on the heels of a successful three minute flight where the X51 broke mach 5. There were four of these hypersonic vehicles built, but after a string of problems, just one is left.