The X-51A Waverider, seen here during a fitting test last July, is a combined effort of the Air Force Research Laboratory and DARPA (the Defense Advanced Research Projects Agency), along with Boeing and Pratt & Whitney Rocketdyne.
May 24, 2010 2:23 PM PDT
Photo by: U.S. Air Force photo/Chad Bellay
| Caption by: Jonathan Skillings
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