U.S. Military lost contact with the new UAV Drone Falcon Hypersonic Test Vehicle HTV-2 1208111.

The Falcon Hypersonic Test Vehicle (HTV-2) had successfully separated from the launch vehicle and was performing "glide phase" maneuvers meant to test its aerodynamics when contact was lost, according to an 11 a.m. (ET) Twitter post from the Defense Advanced Research Projects Agency (DARPA). The latest tweet, at 12:30 p.m. said downrange trackers were unable to relocate the HTV2 but the vehicle "has an autonomous flight termination capability".

The hypersonic aircraft was intended to eventually land in the Pacific Ocean.

The vehicle was launched by a Minotaur IV rocket from Vandenberg Air Force Base in California and re-entered the atmosphere over the Pacific. The launch, originally slated for Wednesday but then scrubbed because of weather, was not broadcast live.

This was the second run for the craft. In April 2010 ended with the aircraft crashing into the Pacific after a loss of contact nine minutes into the flight. But those nine minutes provided some key information about flying 22 times faster than a commercial jetliner.

Thursday's flight was to test control and communications capabilities, as well as heat resistance and other effects of hypersonic flight.

DARPA's goal is to create an aircraft capable of reaching any target in the world in less than an hour.

The triangular wedge of zoom is capable of reaching Mach 20 - approximately 13,000 miles per hour - according to DARPA. At such speeds in Earth's atmosphere, friction subjects the vehicle to temperatures of more than 3,500 degrees Fahrenheit.

As DARPA said on the HTV-2 site, at that speed "air doesn't travel around you - you rip it apart."