US military scientists on Thursday launched a hypersonic aircraft but lost contact with the experimental plane in its second test flight, officials said. The unmanned Falcon Hypersonic Technology Vehicle (HTV-2), designed as a global bomber prototype capable of a mind-boggling 20 times the speed of sound, launched successfully from California aboard a Minotaur IV rocket, according to the Defence Advanced Research Projects Agency.
But after the plane separated from the rocket in the upper reaches of the atmosphere for its "glide" phase, contact was lost, DARPA said. "Range assets have lost telemetry with HTV2," DARPA wrote in a Twitter post after the launch. The agency provided no other details about the flight or how long it had been separated from the rocket.