DARPA: HTV-2 hit Mach 20 before crash

A superfast unmanned military plane traveled at 20 times the speed of sound and managed to control itself for three minutes before crashing into the Pacific Ocean in a recent test, military officials said.

The prototype Falcon Hypersonic Technology Vehicle 2 (HTV-2), billed as the fastest aircraft ever built, splashed down in the Pacific earlier than planned on Aug. 11 shortly after launching from California's Vandenberg Air Force Base on its second-ever test flight.

The HTV-2 experienced some sort of anomaly, prompting the vehicle's autonomous flight safety system to guide it to a controlled splashdown, according to the Defense Advanced Research Projects Agency (DARPA), which oversaw the flight.

Despite the problem, the aircraft reached speeds around Mach 20 (about 13,000 mph) and was able to control its flight for several minutes, officials said.