"It's been an outstanding, record-breaking day," lead propulsion engineer Lawrence Huebner told a post-flight briefing.

NASA's 12-foot-long (3.6 meter) X-43A research vehicle -- resembling a winged surfboard -- hit slightly over Mach 7, about 5,000 mph (8,000 km/h), during 11 seconds of powered flight before gliding at hypersonic speeds for several minutes and finally plunging into the ocean.

The test, conducted off the southern California coast, marked the first time that a "scramjet," or supersonic-combustion ramjet, has powered a vehicle at such high speed.

"The ramjet-scramjet is the Holy Grail of aeronautics in my mind," project manager Joel Sitz told the briefing. "If you go from ground to space, you need to use a ramjet-scramjet if you're going to do it in the most efficient way you can."

Rather than carrying both the fuel and oxygen needed to provide acceleration, like a conventional rocket engine does, scramjet engines carry only hydrogen fuel and pull the oxygen needed to burn that fuel from the atmosphere.

Researchers at the NASA Dryden Flight Research Center at Edwards Air Force Base, on the western edge of the Mojave Desert north of Los Angeles, hope the new engine will revolutionize aviation, speeding the development of significantly faster aircraft and lowering the cost of launching payloads.

Huebner said the test had set a world speed record for a craft powered by an air-breathing engine.

"To put this in perspective, a little over 100 years ago a couple of guys from Ohio flew for 120 feet in the first controlled powered flight," he said, referring to the Wright brothers.

"Today, we did something very similar in the same amount of time, but our vehicle under air-breathing power went over 15 miles."

Project members said the successful test had important commercial and military implications.

"Efficient access to space opens up a whole new world for industry in the future, to be able to get to space and get back, quickly, and do it several times a month," Sitz said.

Project chief engineer Griffin Corpening said NASA had shown what was possible. "Now business and industry and the military can come forward with confidence that they can now use this kind of a propulsion system," he said.

The first test of the X-43A in June 2001 ended in failure after a malfunction in the booster rocket attached to the test vehicle forced NASA scientists to blow up the plane.

During Saturday's test, a modified B-52 bomber dropped the X-43A at an altitude of around 40,000 feet.

A rocket attached to the 2,800-pound (1,270-kg) research vehicle then boosted it to an altitude of 95,000 feet, setting the stage for the scramjet engine test.

Later this year, NASA researchers hope to test the engine at Mach 10, or about 7,000 mph (11,265 km/h), as part of their Hyper-X program.

The vehicle used in Saturday's test will not be recovered from the ocean due to the high cost of such an effort.