Only Hypersonic Test Flight Planned For This Fiscal Year
The X-51A WaveRider will make its first hypersonic flight test
attempt from Edwards Air Force Base on Tuesday, May 25. The
unmanned aerial vehicle will be released from a B-52 bomber off the
southern California coast.
The X-51A is expected to fly autonomously for five minutes --
powered by a supersonic combustion ramjet (scramjet) motor --
accelerate to about Mach 6 and transmit large amounts of data to
ground stations before it splashes down into the Pacific and breaks
up, as planned. There are no plans to recover the flight test
vehicle, one of four built.
"In those 300 seconds, we hope to learn more about hypersonic
flight with a practical scramjet engine than all previous flight
tests combined," said Charlie Brink, X-51A program manager with the
Air Force Research Laboratory's Propulsion Directorate at
Wright-Patterson Air Force Base. The longest previous hypersonic
scramjet flight test, performed by a NASA X-43 in 2004, was faster,
but lasted only about 10 seconds and used less logistically
supportable hydrogen fuel.
The X-51A program is a collaborative effort of the Air Force
Research Laboratory and the Defense Advanced Research Projects
Agency, with industry partners The Boeing Company and Pratt &
The May 25 attempt will be the only hypersonic flight attempt
this fiscal year, a change from the original test plan, which was
to fly once in December 2009 and three more times in 2010. A
combination of factors, including high demand for flight-test and
range assets such as the B-52, contributed to the pause.
"This is an experimental X-plane and it's a complicated test. We
knew the original schedule was aggressive and we would need to be
flexible," said Brink. "It's also expensive to keep a staff of
engineers and support staff at the ready and then not be able to
fly when supporting assets aren’t available. So we elected to
make only one hypersonic try this spring and then pause for a few
months to conserve funding."
Alex Lopez, Boeing vice president of Advanced Network &
Space Systems, said the X-51A program will pave the way to
hypersonic weapons and future access to space.