X-43 BLOWN UP DURING TEST FLIGHT.

Byline: Charles F. Bostwick Staff Writer

EDWARDS AIR FORCE BASE - NASA's attempt Saturday to return to hypersonic flight research for the first time in 32 years ended in an explosion.

The Pegasus booster rocket carrying a tiny research X-43 aircraft was ordered to self-destruct after it veered to one side, then started tumbling, seconds after it was dropped by a NASA B-52 over the Pacific Ocean, officials said.

``As it began its ascent ... it started to veer off its trajectory,'' said Chris Rink, spokesman for the National Aeronautics and Space Administration. ``The mission director decided to terminate the launch.''

Blown apart by remote control, the rocket and the X-43 wreckage fell into the ocean inside a Navy weapons test range off the Southern California coast, officials said.

Wedge-shaped, only 12 feet long, and controlled by computers, the X-43 is really more jet-powered missile than airplane. But it is part of a $185 million project to test in flight an experimental, extremely high-speed jet engine called a scramjet.

The X-43 is NASA's first test program dedicated to hypersonic research since the last X-15 rocket plane flight at Edwards Air Force Base in 1969.

The X-15's fastest flight was Mach 6.7, or about 4,520 mph, with W.J. ``Pete'' Knight, now the Antelope Valley's state senator, at the controls.

The X-43 is hoped to hit Mach 10, or about 6,600 mph.

Scramjet engines are seen as a way to power future high-speed aircraft - able to fly faster than Mach 5, or about 3,500 mph - or reusable space launchers.

While a rocket engine must carry oxygen as well as fuel, a scramjet pulls its oxygen from the air - reducing the weight a launch craft must carry to orbit.

Unlike a conventional jet engine, a ramjet has no rotating blades to compress the air. Scramjets are ramjet engines in which the air flowing through the engine remains supersonic, hence the name, which stands for ``supersonic combustion ramjet.'' That makes them hard to test on the ground.

While Saturday's test was aborted before the X-43 even ignited its engine, Rink said he did not know if the launch problem was confined to the Pegasus, a commercially produced booster rocket.

Rink said NASA will convene an investigative board to look into what went wrong and what should be done before the flight of the second X-43, which originally was to be launched six months after the first test.

If Saturday's test had gone as planned, the winged Pegasus rocket would have boosted the X-43 to about 95,000 feet and Mach 7.

Then the X-43 would have separated and ignited its scramjet for about 10 seconds of powered flight.

Even without the destruction of the booster after launch, the X-43 would not have survived the flight. The flight was designed to end with the X-43 splashing into the Pacific Ocean.

Another X-43 has been built and is being prepared for the program's second flight. A third X-43 is being built.

CAPTION(S):

2 photos

Photo:

(1) The X-43 and its Pegasus booster rocket were ordered to self-destruct during Saturday's test flight in the Pacific.

(2) The wedge-shaped, 12-foot-long, computer-controlled X-43 is really more of a jet-powered missile than an airplane.

Jeff Goldwater/Staff Photographer