X-34 parked next to L-1011 carrier aircraft. Photo: NASA

NASA's X-34 experimental rocket plane program has kicked off a new phase of tests to prepare it for flight.

Following initial captive flight tests last year at NASA's Dryden Flight Research Center, Edwards Air Force Base, Calif., the X-34 technology demonstrator began a new series of tests last week in which it is being towed behind a semi-truck and released to coast on the Edwards dry lakebed. On Thursday, it was towed and released twice at speeds of five and 10 miles per hour. On Monday, it was towed and released twice at 10 and 30 miles per hour. The X-34 technology demonstrator is being developed for NASA's Marshall Space Flight Center in Huntsville, Ala. by Orbital Sciences Corp., of Dulles, Va.

"We are off to a very good start," explained Jeff Sexton at the Marshall Center. Sexton is flight-testing and operations project manager for the Pathfinder Program ‹ which includes the X-34. "We are very pleased with the results of these early tests. If we have any vehicle anomalies we want to find them in ground tests not in flight or landing."

Twelve tests are planned during which the X-34 will be towed for distances up to 10,000 feet and released at speeds up to 80 miles per hour. The test series is expected to last at least six weeks.

"The tests, which simulate the vehicle's roll-out after landing, will verify the craft's guidance and navigation system, nose wheel steering, braking, rudder speed brake operation and rudder steering," Sexton said.

For these tests, the X-34 is attached to the tow truck by a specially designed 500-foot cable. A radio link is used to provide communications between the rocket plane and the tow truck launch panel operator.

"We're pleased to begin another series of testing for the X-34 that will bring us one step closer to flight," said Antonio Elias, senior vice president and general manager of Orbital's advanced programs group. "When completed, they will provide valuable data and help ensure the success of the flight program."

After completion of ground testing, the X-34 will be attached to Orbital's L1011 carrier aircraft, Stargazer, to finish captive-carry flights required by the FAA to verify that the combined aircraft are safe to fly. Plans are to follow the certification program with approach and landing flights of the X-34 at White Sands Missile Range, NM.

The X-34 is a flying laboratory for technologies, operations and experiments applicable to future low-cost, reusable launch vehicles. It is one of a family of technology demonstrators aimed at lowering launch costs from $10,000 to $1,000 a pound.

The suborbital X-34 is 58.3 feet (17.77 meters) long and 27.7 feet (8.44) meters wide. It is capable of flying up to eight times the speed of sound and reaching altitudes of approximately 50 miles.