An experimental unmanned hypersonic glider has been launched from an air base on the central California coast.
A rocket carried the agency's Falcon Hypersonic Technology Vehicle-2 (HTV-2) to the edge of space, where it separated from the booster to maneuver through the atmosphere at 13,000 mph. Minutes into the flight, the agency tweeted that the mission was on track in its glide phase. The mission will end with a plunge into the ocean.
A similar vehicle was launched last year and returned nine minutes of data before contact was prematurely lost.
The U.S. military is trying to develop technology to respond to threats around the globe at speeds of Mach 20 or greater.
That is much in keeping with DARPA's stated mission: "Creating & Preventing Stategic Surprise."
Explaining the reason for the test, DARPA states on its site:
"How do you learn to fly at 13,000 miles per hour-a speed at which it would take less than 12 minutes to get from New York to Los Angeles? Or, how do you know whether a vehicle can maintain a long-duration flight while experiencing temperatures in excess of 3,500 degrees Fahrenheit-hotter than a blast furnace that can melt steel? And if you can fly, and withstand the extreme heat, how do you know if the vehicle can be controlled as it rips apart the air? How? You try it."
Update: Contact was lost after the experimental craft began flying on its own, DARPA said after the launch.
The problem occurred during the critical point of transition to aerodynamic flight, DARPA said in a statement that described the mission as an attempt to fly the fastest aircraft ever built.
"More than nine minutes of data was collected before an anomaly caused loss of signal," it said. "Initial indications are that the aircraft impacted the Pacific Ocean along the planned flight path."
The 7:45 a.m. launch from Vandenberg Air Force Base, 130 miles (200 kilometers) northwest of Los Angeles, was the second of two planned flights of a Falcon Hypersonic Technology Vehicle-2. Contact was also lost during the first mission.
Shaped like the tip of a spear, the small craft is part of a U.S. military initiative to develop technology to respond to threats at 20 times the speed of sound or greater, reaching any part of the globe in an hour.