NASA was forced to destroy the prototype of an experimental hypersonic jet on Saturday, 2 June, minutes before its engine was due to ignite.
The unmanned X-43a carried a revolutionary 鈥渟cramjet鈥� engine designed to power it to Mach 7 鈥� seven times the speed of sound. The engine sucks oxygen out of the atmosphere, rather than carrying it on board. It then uses the oxygen to combust hydrogen fuel. Previous 鈥渁ir-breathers鈥� have managed only Mach 5.
The test flight began as planned. A converted B-52 bomber took off from the Dryden flight research centre in California, carrying the X-43a coupled to a Pegasus rocket. The bomber then released the rocket 鈥渟tack鈥� at about 7,000 metres. The booster rocket was then supposed to lift the jet to 29,000 metres, when the scramjet engine would kick in.
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But five seconds after the rocket ignited, pilots in chase planes reported that it began to career off course and tumble end over end.
Within seconds, flight controllers decided to abort the mission, and remotely detonated explosives onboard the jet. The debris hit the Pacific Ocean.
鈥淭hey had to terminate it. It has a predetermined trajectory and it was going off that,鈥� a NASA spokeswoman said.
NASA is now assembling a team of specialists to investigate the accident. They are likely to centre their attention on the modifications made to the Pegasus booster in order for it to carry the jet.
NASA spokesman Alan Brown says: 鈥淭here was such a high level of instrumentation on both vehicles that we are confident the cause of the anomaly will be found and then corrected.鈥�
Although the loss of the X-43a will be a blow to the engineers, NASA points out that it was an experimental flight. Two more identical prototypes have yet to be tested.
NASA scientists hope that by dramatically cutting the weight of onboard fuel, the scramjet engine will help revolutionise air and space travel.