NASA's experimental X-43A hypersonic research vehicle was successfully launched Saturday, demonstrating for the first time an airbreathing scramjet-powered aircraft while soaring 95,000 feet above the Pacific Ocean at seven times the speed of sound.

The Pegasus rocket and X-43A fall away from B-52 carrier jet. Credit: NASA/Jim Ross

"Today was a grand-slam in the bottom of the 12th," said Joel Sitz, X-43A project manager from NASA's Dryden Flight Research Center. "It was fun all the way to Mach 7. We separated the research vehicle from the launch vehicle, as well as separating the real from the imagined."

The experiment was part of NASA's high-risk, $250 million Hyper-X program that seeks alternate propulsion technologies for access to space and high-speed flight within the atmosphere.

A scramjet operates by supersonic combustion of fuel in a stream of air compressed by the high forward speed of the aircraft itself, as opposed to a normal jet engine, in which fan blades compress the air.

In order to test the scramjet, the 12-foot-long, five-foot-wide X-43A vehicle was blasted high above Earth on the end of a solid-fueled Pegasus rocket booster.

The single-stage Pegasus was carried from California's Edwards Air Force Base to a position 50 miles off the Southern California coast by a B-52B aircraft, then dropped at an altitude of 40,000 feet at 2200 GMT (5:00 p.m. EST; 2:00 p.m. PST).

After free-falling for five seconds, the Pegasus ignited for an 80-second firing.

The Pegasus booster fires into the sky with X-43A. Credit: NASA/Jim Ross

Once the rocket motor had burned out, the 2,800-pound X-43A was released to fly on its own and perform its history-making experiment at nearly 5,000 mph.

The supersonic combustion ramjet, or scramjet, operated for about 10 seconds -- the duration of its hydrogen fuel supply.

"It's been a great, record-breaking day," said Larry Huebner, Hyper-X propulsion lead from NASA's Langley Research Center. "We achieved positive acceleration of the vehicle while we were climbing, and maintained outstanding vehicle control. This was a world-record speed for air-breathing flight."

Controllers gathered several additional minutes of data as X-43A glided back to Earth, eventually splashing down in the Pacific approximately 450 miles off the coast about 10 minutes after launch.

The X-43A vehicle and engine were built by ATK GASL, formerly MicroCraft, of Tullahoma, Tennessee. Boeing Phantom Works in Huntington Beach, Calif., designed the thermal protection and onboard systems. The booster is a modified Pegasus rocket built by Orbital Sciences Corp. Chandler, Ariz.

An artist's concept of X-43A mission sequence. Credit: NASA

Researchers believe the Hyper-X technologies may someday offer more airplane-like operations and other benefits compared to traditional rocket systems. Rockets provide limited throttle control and must carry heavy tanks filled with liquid oxygen, necessary for combustion of fuel. An air-breathing engine, like that on the X-43A, scoops oxygen from the air as it flies. The weight savings could be used to increase payload capacity, increase range or reduce vehicle size for the same payload.

The test flight came nearly three years after an initial X-43A launch was destroyed moments after it began when the Pegasus rocket booster veered off course. Investigators reported there was no single contributing factor, but the root cause of the problem was identified as the control system of the booster.

"After several years of detailed analysis, design upgrades and testing to address the factors that contributed to the failure of the program's first flight, it is all the more gratifying to have carried out this successful flight test," said Ron Grabe, executive vice president and general manager of Orbital's Launch Systems Group.

"Our congratulations go out to NASA and all the partners on this program who persevered to get it right. We now have our sights set on a successful third mission to provide even more critical data to NASA's research into the field of hypersonic flight and to extend the flight speed record set today to Mach 10," Grabe added.