Searchbar'd and googled this but nothing came up. This is fuckin crazy if you ask me...
http://www.latimes.com/business/money/la-fi-mo-darpa-hypersonic-missile-20120420,0,4564567.story
The results are in from last summer’s attempt to test new technology that would provide the Pentagon with a lightning-fast vehicle, capable of delivering a military strike anywhere in the world in less than an hour.
In August the Pentagon's research arm, known as the Defense Advanced Research Projects Agency, or DARPA, carried out a test flight of an experimental aircraft capable of traveling at 20 times the speed of sound.
After reaching an undisclosed altitude, the aircraft jettisoned from its protective cover atop the rocket, then nose-dived back toward Earth, leveled out and glided above the Pacific at 20 times the speed of sound, or Mach 20.
But it was ended about nine minutes into flight for unknown reasons. The launch had received worldwide attention and much fanfare, but officials didn’t provide much information on why the launch failed.