Spelling disappointment for the NASA- and Pentagon-funded WaveRider project, the test flight of the hypersonic aircraft ended in a failure on Tuesday, when the plane plunged into the Pacific Ocean even before the firing up of its hypersonic engine.

The failed test flight of the unmanned X-51A WaveRider crashed the dreams of long-haul flights taking a fraction of the time they take at present, as the aircraft was designed to achieve a speed of 3,600 miles per hour (mph), after by a B-52 bomber dropped it off the Southern California coast on Tuesday.

With the plan behind the test flight being that the unmanned jet could sustain a speed of up to 4,500 mph during its five-minute flight above the Pacific, it was being hoped by the aircraft's engineers that the WaveRider could sustain top speeds for a two-fold longer duration than an earlier X-51A plane.

However, the WaveRider test flight was disastrous because the hypersonic scramjet engine of the aircraft did not even get the chance to fire up. When the plane was barely 15 seconds into the flight, it developed some problem with its control fins, lost control, and finally plunged into the Pacific.

About WaveRider's failed test flight, Charlie Brink - program manager for the Air Force Research Laboratory - said in a statement that the problem with the subsystem "caused a termination before we could light the scramjet engine;" and added: "All our data showed we had created the right conditions for engine ignition and we were very hopeful to meet our test objectives."