A fault with one of the X-51A’s cruiser control fins caused it to fail during flight Tuesday, according to the Air Force.
The Air Force’s experimental unmanned hypersonic X-51A WaveRider successfully launched from an Air Force B-52 bomber over Point Mugu Naval Air Warfare Center Sea Range, Calif., at approximately 2:35 p.m. EST, and the rocket booster fired as planned, the Air Force said. After 16 seconds, a fault was identified with one of the cruiser control fins. Once the X-51A separated from the rocket booster approximately 15 seconds later, the vehicle was unable to maintain control due to the faulty control fin and failed, according to the Air Force.
“It is unfortunate that a problem with this subsystem caused a termination before we could light the Scramjet engine,” Air Force Research Laboratory (AFRL) X-51A Program Manager Charlie Brink said in a statement. “All our data showed we had created the right conditions for engine ignition and we were very hopeful to meet our test objectives.”
The Air Force said this particular control subsystem had proven reliable in the previous two flights of the X-51A, including a May 2010 flight when the Waverider flew for more than three minutes at Mach 4.88 under scramjet power, nearly five times the speed of sound.
One of the four X-51A vehicles remains and AFRL officials have not decided when, or if, that vehicle will fly, the Air Force said.
The X-51A Waverider program is a collaborative effort of the AFRL, the Defense Advanced Research Projects Agency (DARPA), GenCorp [GY] Rocketdyne and Boeing [BA] to demonstrate hypersonic flight capability, which is speeds above Mach 5. Rocketdyne provides the propulsion system while Boeing supplies the vehicle integration, according to a Boeing statement.