Nasa hypersonic jet fails

Nasa has aborted the test flight of a hypersonic jet designed to fly at a record-breaking seven times the speed of sound.

Seconds after launch Nasa cameras aboard two F-18 chase planes showed the Pegasus rocket, which was intended to launch the X-43A jet, careering off course and falling out of control from the sky.

We are obviously disappointed in this, but we're going to find out what happened, fix it and fly again successfully

Vince Rausch

X-43A programme manager

Controllers triggered on-board explosives to destroy both rocket and X-34A at about 7,200 metres (24,000 feet) over the Pacific Ocean.

Pieces of the booster rocket and the small, black X-43A prototype, part of Nasa's Hyper-X programme, fell into the sea.

"They had to terminate it. It has a predetermined trajectory and it was going off that," Nasa spokeswoman Leslie Williams said.

Investigation underway

Within hours, Nasa began assembling a team to investigate what went wrong.

"The vehicle was very highly instrumented so we are hopeful and confident that we will have a lot of data to analyse and to reconstruct what happened," said Kevin Petersen, director of Nasa's Dryden Flight Research Centre.

Nasa was aiming to beat the world record of Mach 6.7, over six times the speed of sound, set by the rocket-powered X-15 in 1967.

The Pegasus booster rocket was released from a B-52 plane. The X-43A jet was piggybacking on the rocket and was due to separate from it when the Pegasus had boosted it to an altitude of 28 kilometres (17.3 miles).

But within seconds of the launch the Pegasus rocket was malfunctioning. Before now the 10-year-old Pegasus has only failed twice in over 100 launches from a B-52.

Out of control

"The Pegasus went out of control; it appeared parts were breaking off of it," said a Nasa spokesman.

The Pegasus rocket was carried under the wing of the B-52

The surfboard shaped jet began its journey from the Edwards Air Force Base in California.

Once released from Pegasus, it would have flown using its specialised scramjet engine.

The engine sucks oxygen from the atmosphere as it flies, using the oxygen to burn a small amount of hydrogen for fuel.

This eliminates the need for heavy, expensive, liquid oxygen tanks.

Way ahead

The jet is at the forefront of new technology that could eventually change the way people and payloads get into space.

It is designed to accelerate to Mach 7 and Mach 10. By contrast, a jet fighter plane travels at speeds of Mach 1 to Mach 2.

The $185m project aims to fly three of the planes over the next 18 months. Data collected during the flights will be used to build larger planes capable of carrying a pilot.

It is not yet known when the second experimental plane will be able to fly.

"We are obviously disappointed in this, but we're going to find out what happened, fix it and fly again successfully," said Vince Rausch, the X-43A program manager.