Search This Blog

Monday, November 3, 2014

SpaceShipTwo's Rocket Engine Did Not Cause Fatal Crash

As reported by Discovery: It wasn't SpaceShipTwo’s hybrid rocket motor -- which was flying on Friday with a new type of fuel -- that caused the fatal crash, the head of the accident investigation agency said late Sunday.

The ship’s fuel tanks and its engine were recovered intact, indicating there was no explosion.
“They showed no signs of burn-through, no signs of being breached,” Christopher Hart, acting chairman of the National Transportation and Safety Board, told reporters at the Mojave Air and Space Port in Mojave, Calif.

Instead, data and video relayed from the ship show its hallmark safety feature -- a fold-able tail section designed for easy re-entry into the atmosphere from space -- was deployed early.

“The engine burn was normal up until the extension of the feathers,” said Hart.

Normally, the feather system wouldn't be unlocked until the rocket-powered spaceship is moving about Mach 1.4, or 1.4 times faster than the speed of sound.

Instead, the co-pilot moved the lever from locked to unlock when the spaceship was traveling at about Mach 1, Hart said.

“I’m not stating that this is the cause of the mishap,” he added. “We have months and months of investigation to determine what the cause was.”

In addition to the possibility of pilot error, Hart said the NTSB is looking into a variety of other issues that may have caused or contributed to the accident, including training, spacecraft design and the safety culture at Virgin Galactic and Scaled Composites, which designed and manufactured the spaceship.

“There is much more that we don’t know and our investigation is far from over,” Hart said.

The accident claimed the life of Scaled Composites test pilot Mike Alsbury, who was serving as the spaceship co-pilot, Scaled’s website shows. Pilot Pete Siebold, who was able to parachute to the ground, survived with a serious shoulder injury.

SpaceShipTwo took off on Friday morning for what was expected to be its fourth powered test flight. It was released as planned from its carrier jet at an altitude of about 45,000 feet. Seconds later, the spaceship’s hybrid motor, which was using a new plastic propellant, powered up.

About nine seconds later, the ship’s feathering system was unlocked, said Hart. Two seconds after that, the ship’s tail section moved toward the deployed position.

"This was an uncommanded feather, which means the feather occurred without the feather lever being moved into the feather position," Hart told Discovery News.
“Shortly after the feathering occurred, the telemetry data terminated and the video data terminated,” he said.

Debris was scattered over a five-mile area north of the spaceport, indicating the spaceship broke apart in flight.

About 800 people already have paid or put down deposits to fly on SpaceShipTwo. Virgin Galactic hoped to begin passenger service next year. The company's second ship is about 65 percent complete.