NASA'S X-43 HITS MACH 7 SCRAMJET-POWERED CRAFT PERFORMED 'BEAUTIFULLY,' SAYS PROJECT MANAGER.

Byline: Greg Botonis and Charles F. Bostwick Staff Writers

EDWARDS AIR FORCE BASE - NASA's tiny, unmanned X-43A test craft topped 4,900 mph Saturday before plunging as planned into the Pacific Ocean.

Dropped from a B-52, the 12-foot-long wingless X-43A tested an ultra- high-speed engine called a scramjet in a hoped-for confirmation of work that hypersonic researchers have been doing on the ground.

``We went through all of our segments without a hitch. Everything went beautifully,'' said Joel Sitz, project manager for the X-43A.

The experimental scramjet - supersonic combustion ramjet - is being tested in a $230 million program to develop technology for possible use in future space launch vehicles and for high-speed military and civilian aircraft.

A scramjet pulls oxygen for combustion from the atmosphere rather than carry the extra weight of its own oxygen as a rocket does. By not having to carry oxygen, a spacecraft can save fuel weight and carry more equipment.

The first attempt at flying an X-43, in June 2001, ended with controllers intentionally destroying the craft when the Pegasus booster rocket carrying it went out of control after the rocket's control fins broke off.

Several factors were blamed for the 2001 malfunction, one of them the launching of the booster rocket-mounted X-43 at 23,000-foot altitude, where the atmosphere is much denser than the 40,000-foot level at which Pegasus rockets are launched when they go into space.

The booster's fin actuator system was beefed up for Saturday's test, and the rocket was to be let go at 40,000 feet.

The NASA B-52 carried the booster-mounted X-43A from Edwards Air Force Base over the Naval Air Warfare Center Weapons Division Sea Range off the central California coast.

On release from the converted bomber, the Pegasus booster rocket fired, propelling the X-43 to an altitude of 95,000 feet and a speed of Mach 7, roughly 4,900 mph.

As the booster engine burned out, the X-43 separated and fired its scramjet engine for about 10 seconds. Then it performed a set of preprogrammed maneuvers before crashing into the ocean.

Although the scramjet runs just seconds, the test's data is hoped to validate wind-tunnel tests and other ground research, NASA officials say.

Plans call for flying one other X-43A vehicle, which will hit a top speed of about 7,000 mph.

Counting the X-43 that was destroyed, NASA is spending $230 million on the research program.

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 1968.

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

Greg Botonis, [phone]

gregory.botonis(at)dailynews.com

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NASA used a converted B-52, shown taking off Saturday from Edwards AFB, in a test of its X43A - powered by an experimental scramjet engine - which reached Mach 7.