EDWARDS AIR FORCE BASE, California (CNN) — The X-43A, a "hypersonic" experimental aircraft attached to a Pegasus booster rocket, failed the first of three planned test flights Saturday.
The flight plan called for the X-43A to separate from the booster rocket and free-fall back to earth in about 10 seconds, landing in the Pacific Ocean. Instead, the aircraft fell directly into the ocean.
The aircraft was launched 95,000 feet above the Pacific Missile Test Range here, from a NASA B-52.
NASA had hoped the aircraft would reach speeds up to seven times the speed of sound, or almost 5,000 miles per hour.
Two other planned test are now on hold, officials said.
The hypersonic combustion engine technology, an elusive engineering goal for decades, could someday allow craft to fly 10 times faster than the speed of sound, a pace now reserved to conventional rockets.
It's called "scramjet" technology, and it relies on air-breathing engines instead of rocket power to achieve its tremendous speeds. Currently, the SR-71 holds the title as the fastest air-breathing plane in the world. It has cruised slightly above Mach 3, or three times the speed of sound. A plane flying at the speed of sound can travel a mile in about five seconds.
Two other tests of the of the $185 million Hyper-X flight research program planned for later this year and late next year, have been put on hold.
MicroCraft, Inc. of Tullahoma, Tenn., is the industry partner chosen by NASA to construct the X-43 vehicles. Orbital Sciences Corporation's Launch Vehicles Division in Chandler, Ariz. will construct the Hyper-X launch vehicles.
The proposed X-43 hypersonic plane would be a marked improvement over a conventional rocket-powered craft, NASA said. The former uses atmospheric oxygen to combust its fuel.
But the latter must carry its own supply of the element, considerably increasing its weight. Hypersonic is defined as traveling at a speed equal to about five times the speed of sound or greater.
The scramjet has a simple mechanical design with no moving parts. Rather than using a rotating compressor like a turbojet engine, the forward movement compresses air into the engine.
Fuel, in this case hydrogen, is injected and the expanding hot gases from combustion accelerate the exhaust air and create thrust.
Scramjet technology could also allow more traditional aircraft to greatly reduce flight times and costs. Practical applications could be possible within decades, according to NASA.