Article Posted on : - May 27, 2010

The X-51A WaveRider missile. A Boeing Photo

WASHINGTON (AFP): The US Air Force has test launched a hypersonic cruise missile, with the vehicle accelerating to Mach 6 before splashing down in the Pacific Ocean, officials said.

The Air Force said the test flight of the X-51A Waverider lasted more than 200 seconds, the longest ever hypersonic flight powered by scramjet propulsion. The previous record was 12 seconds in a NASA X-43 vehicle.

�We are ecstatic to have accomplished most of our test points on the X-51A�s very first hypersonic mission,� said Charlie Brink, programme manager with the Air Force Research Laboratory at Wright-Patterson Air Force Base in Ohio.

�We equate this leap in engine technology as equivalent to the post-World War Two jump from propeller-driven aircraft to jet engines,� he said Wednesday.

But about 200 seconds into the flight, �a vehicle anomaly occurred and the flight was terminated,� the Air Force said in a statement.

�Engineers are busily examining the data to identify the cause of the problem,� it said.

The Waverider was launched from Edwards Air Force Base in California Wednesday, then carried under the wing of a B-52 aircraft before being released at an altitude of 50,000 feet off the Pacific coast.

A solid rocket booster then propelled the vehicle to about a speed of about Mach 4.8, before the X-51's special scramjet engine ignited.

The Waverider, built by Boeing and Pratt and Whitney Rocketdyne, reached an altitude of 70,000 feet and a top speed of Mach 6, the Air Force said.

Hypersonic flight begins at Mach 5, or five times the speed of sound.

The X-51 fits in with US plans to hit distant targets with conventional weapons within an hour, dubbed �prompt global strike.�

The Waverider, or an experimental hypersonic plane also under development, could substitute for a ballistic missile armed with a conventional warhead, as other countries might suspect the missile represented a nuclear attack.