DARPA's 13,000mph plane lost but not forgotten (images)

The Twitter feed from the Defense Advanced Research Projects Agency (DARPA) said that the agency lost track of its hypersonic Falcon HTV-2 aircraft during its second and final test flight Thursday. The Falcon HTV-2 was said to reach Mach 20 or 13,000 miles per hour during its 9-minute flight before it disappeared and presumably plunged into the Pacific. At this speed, the aircraft could travel from New York to Los Angeles in under 12 minutes. Its purpose is to provide the military with the ability to strike anywhere in the world within an hour.

Check out the CBS News story for current updates.

The goal of the  Falcon HTV-2 is to travel anywhere in the world in under an hour. It actually reached Mach 22 in its first test in April.

This DARPA chart shows the planned route for the Falcon HTV-2. Click to enlarge.

This is an earlier photo of the Minotaur IV rocket that launched the Falcon HTV-2 on its test flight.

When fully active the Falcon HTV-2 will be launched from the air.

The Falcon HTV-2 gains speed by going into orbit and then reentering the Earth's atmosphere.

DARPA says the tests on its test flight will address three key challenges to building a plane that can go so fast. The first is Aerodynamics. This type of speed has never been reached in Earth's atmosphere so high-speed wind tunnel tests, computer simulations, and flight tests are necessary to understand the extreme pressure.

Antithermal effects need to be determined as the Falcon HTV-2 will reach surface temperatures of 3500°F

Guidance, navigation and control requires quick responses to any obstacle. Darpa uses the example encountering a pothole while traveling at 3.6 miles per second.