Wright-Patterson AFB, Ohio – Air Force engineers currently plan to fly the second X-51A Waverider hypersonic flight test demonstrator as early as March 22, program officials said March 15.
Four X-51As were built for the Air Force by teams at Boeing and Pratt & Whitney Rocketdyne. The X-51A made history on its inaugural hypersonic flight test on May 26, 2010, when it was launched from Edwards Air Force Base, Calif., tucked under the wing of a B-52 Stratofortress. After release, it ultimately accelerated to Mach 5 under scramjet power. The flight was about 10 times longer than any previous hypersonic scramjet flight and “80 to 90 percent” of flight test objectives were achieved, program officials said.
Here is a link to the story at the US Air Force website.