X-51A Falls Short in Third Flight

An experimental X-51A Waverider hypersonic vehicle crashed into the Pacific Ocean after a control fin malfunctioned during a test shot off the California coast, said Air Force officials on Aug. 15. The malfunction prevented the vehicle’s supersonic combustion ramjet engine from igniting and propelling the vehicle for upwards of five minutes at speeds around Mach 6, they said in a release. “It is unfortunate that a problem with this subsystem caused a termination before we could light the scramjet engine,” said Charlie Brink, the Air Force Research Lab’s X-51A program manager, of the Aug 14 test. The Waverider dropped from the B-52 mothership and successfully boosted through its rocket-propelled first stage. Fifteen seconds after booster separation, however, the X-51 departed controlled flight due to the anomaly and plummeted into the ocean below. “All our data showed we had created the right conditions for engine ignition and we were very hopeful to meet our test objectives,” said Brink. This mission was the third test flight of an expendable X-51 vehicle, following shots in June 2011 and May 2010. AFRL officials said they were uncertain when, or if, they would fly the fourth and final X-51 vehicle. (See also Reuters report.)