A system designed to increase drag upon reentry into the atmosphere deployed prematurely just before the breakup of Virgin Galactic’s SpaceShipTwo that left one Scaled Composites test pilot dead and another injured Oct. 31, the NTSB reported.
SpaceShipTwo, developed by Scaled Composites, is part of Virgin Galactic’s plan to sell tickets for passengers to suborbital space. The rocket-powered space plane is launched from mothership WhiteKnightTwo. During a test flight from Mojave Air and Space Port in California, SpaceShipTwo separated from WhiteKnightTwo and flew for about two minutes before the mishap, officials said in a press conference. Michael Alsbury, the co-pilot for the test flight, was killed. Scaled Composites Director of Flight Operations Peter Siebold, who was the pilot of the flight, survived and was alert and talking Nov. 1, Scaled Composites reported.
Virgin Galactic said in a statement that its partner Scaled Composites conducted a powered test flight during which “the vehicle suffered a serious anomaly resulting in the loss of the vehicle.” The cause of the anomaly, which happened north of the airport, is unknown, but by Nov. 2 the NTSB had begun to piece together details of the sequence of events.
SpaceShipTwo features a feathering wing to control reentry into earth’s atmosphere. After a normal release from WhiteKnightTwo and ignition of the rocket motors, the feathers moved prematurely toward the deployed position, acting NTSB Chairman Christopher Hart said in a media brief Nov. 2.
Two actions are required to deploy the feathers, Hart explained: One handle must be moved from the lock to unlock position, and another, the feathering handle, must be moved to the feather position. Normal procedures call for the lock/unluck handle not to be moved until acceleration to Mach 1.4, he said, but telemetry data and data from a cockpit camera indicate that the pilot in the right seat moved the unlock lever about 9 seconds after the rocket engine ignited, at just above Mach 1.0. Two seconds later, the feathers deployed even though the feather handle had not been moved, he said. Telemetry and video data terminated shortly thereafter, he said. The 5-mile-long debris field is consistent with an in-flight breakup, according to Hart. He stressed that the NTSB is still investigating, and is a long way from determining the probable cause.
“Our primary thoughts at this moment are with the crew and family, and we’re doing everything we can for them now,” said Virgin Galactic Chief Executive George Whitesides. He said the company would support the investigation, “and we’re going to get through it.”
SpaceShipTwo is built from carbon composite construction that was tested and proved on SpaceShipOne. The space plane is carried aloft under WhiteKnightTwo and released horizontally from an altitude as high as 50,000 feet so that the rocket has “to burn only for a very short time in order to reach space,” according to an overview of the space plane on Virgin Galactic’s website. “If there were any problems during the boost phase, the rocket motor could simply be shut down and the spaceship would return as a glider to the runway.”
While the aircraft was flying with a new fuel formation, Scaled Composites President Kevin Mickey said it had been thoroughly tested on the ground. He said that the rocket motor configuration had been flown a few times in the past. Mojave Air and Space Port Chief Executive Stuart Witt added that he “detected nothing that appeared abnormal” on the flight.
“The future rests in many ways on hard days like this,” Whitesides said, adding that we owe it to the pilots and those who have been working hard on the vehicles to understand and move forward.