By Marina Malenic

WEST PALM BEACH, Fla.–The second of four hypersonic vehicles built for an experimental Air Force program is ready for another flight attempt, industry officials here said this week.

The Air Force decided March 24 not to launch the X-51A for a planned four-minute test flight out of Edwards AFB, Calif. A B-52 Stratofortress departed Edwards carrying the test vehicle that day and flew as planned to the designated launch area over the Navy Point Mugu Sea Range. However, test controllers opted not to initiate the test since all required test conditions could not be met, the Air Force said at the time (Defense Daily, March 25). A “subsystem malfunction on the B-52” led to termination of the X-51 attempt, the service later said.

Officials for Pratt & Whitney’s Rocketdyne unit, the company that builds the scramjet engine, said this week that the vehicle was inspected after the aborted launch and is ready for a second attempt.

“The X-51 is fine. It has been inspected and will be ready to fly as soon as we get on the manifest,” Curtis Berger, director of hypersonic programs for the company, told reporters here.

The X-51 WaveRider reached Mach 5 when it flew for the first time in May 2010–at 143 minutes the longest flight of a supersonic combustion ramjet engine, or scramjet (Defense Daily, May 28, 2010).

Boeing [BA] and Rocketdyne are the contractors for the project. Pratt & Whitney is a division of United Technologies [UTX].

Pentagon officials have said they are studying the use of hypersonic weapons in applications such as Prompt Global Strike, a precision missile that could hit any target on earth within two hours. Officials have said there are no plans yet to weaponize the X-51.

The program has produced four Waverider test vehicles and has $250 million in funding. The government’s contract with Boeing and Pratt & Whitney is worth $220 million.

Hypersonic speed describes velocities upward of Mach 5, or five times the speed of sound.