Virgin Galactic pilot actions studied in spaceship crash

Investigators are trying to solve several mysteries about the recent crash of a Virgin Galactic spacecraft during a test flight, including how the pilot managed to escape and survive the crash that killed his co-pilot.

The suborbital rocket vehicle dubbedSpaceShipTwobroke into pieces over California's Mojave Desert and crashed Fridayshortly after its separation from the special jet aircraft that carries it aloft for its high-altitude launches.

Investigatorsare trying to determine how surviving pilot PeteSiebold, 43, managed to get out of the rocket plane and parachute to the ground from a height of roughly 15,000 metres (50,000 feet), an altitude virtually devoid of oxygen.

Hart saidSiebold, now hospitalized with a shoulder injury, did not exit through the cockpit's escape hatch. "We know it wasn't through there, so how did this pilot get out?" he said.

Meanwhile, ahuman-factors expert will join the investigation to study why the co-pilot prematurely unlocked a pivoting tail section of the ship during a test flight, a top safety official said on Monday.

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The untimely engagement of the tail mechanism, designed to slow the vehicle's descent into the atmosphere from space, and the possibility that pilot error was to blame, were disclosed by the National Transportation Safety Board (NTSB) late on Sunday and have emerged as a main thrust of the inquiry into thecrash.

"We know already from having the lever move from lock to unlock that we need to get a human-factors person in here," saidNTSBChairman Christopher Hart. "The question then is why did that happen when it happened?"

Investigators have yet to determine whether releasing the tail mechanism too early caused or contributed to the crash of the space plane near the Mojave Air and Space Port, about 150 kilometres north ofLosAngeles, Hart said in an interview.

Pilot error possible

"I'm not stating that this is the cause of the mishap. We have months and months of investigation to determine what the cause was," Hart said.

Asked if pilot error was a possible factor, Hart said: "We are looking at all of these issues to determine what was the root cause of this mishap ... including that possibility."

Also unclear was exactly how the tail mechanism began to rotate once it was unlocked, since that manoeuvre requires a separate pilot command that was never given, Hart said.

This raised questions about whether the craft's position in the air and its speed somehow enabled the tail section to swing free on its own.

SpaceShipTwo, developed by the fledgling space tourism company of billionaire entrepreneur Richard Branson, was designed to carry wealthy passengers on short rides into space, with Virgin Galactic planning to begin offering its first flights to paying customers next spring.

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About 800 people have paid or put down deposits for a ride into space at $250,000 a seat. Branson plans to be on the first commercial flight with his son.

Branson said Monday his company's venture was "absolutely" worth the risks. "It's a grand program, which has had a horrible setback, but I don't think anybody ... would want us to abandon it at this stage," he told NBC.

The crash came three days after the unmanned rocket of another private space company, Orbital Sciences Corp, exploded during liftoff from a commercial launch pad in Virginia on a mission, under contract with NASA, to deliver cargo to the International Space Station.