The U.S. military launched an experimental hypersonic aircraft on its swan song test flight Wednesday (May 1), accelerating the craft to more than five times the speed of sound in the longest-ever mission for a vehicle of its kind.
Wednesday's flight used the last of four X-51A vehicles built by Boeing for the Air Force experiments. While the previous
Fifteen seconds later, when the X-51A separated from the rocket booster, it lost control due to a "faulty control fin," the
The Air Force conceived the X-51A program in 2004, and the service has spent $140 million on the Waverider system, according