USAF B-52 Stratofortress with X-51A scramjet

An Air Force Flight Test Center B-52 Stratofortress from Edwards Air Force Base, Calif., carries an X-51A Waverider prior to the scramjet’s first hypersonic flight test on March 26, 2010. Air Force engineers have made design modifications to the three remaining X-51A demonstrators and plan to resume the hypersonic flight test program in early spring of 2011. (U.S. Air Force photo)