The National Transportation Safety Board said a co-pilot’s premature deployment of a spacecraft braking system caused the deadly breakup of Virgin Galactic’s SpaceShipTwo VSS Enterprise.
Michael Alsbury, the craft’s co-pilot, died in the Oct. 31, 2014 flight test accident. The NTSB issued its findings on the accident in a hearing at its Washington headquarters July 28.
SpaceShipTwo was a commercial spacecraft that Scaled Composites of Mojave, Calif., built for Virgin Galactic. The craft—designed to reach 60 miles above the Earth prior to gradual descent—broke up during a rocket-powered test flight.
Pilot Peter Siebold was seriously injured in the accident, but he was able to survive by parachuting from the craft.
The test flight by Scaled Composite personnel was staged to test a plastic-based fuel rocket motor in flight.
In the test, SpaceShipTwo was carried to launch altitude by a “mother ship” — a specialized plane, White Knight Two. It then was released to fly to the edge of the Earth’s atmosphere, powered by a rocket engine.
But just 11 seconds later, the craft broke apart, spewing debris over a 35-mile area of the Mojave Desert. An initial finding by the NTSB indicated SpaceShipTwo’s air-braking descent device, or feathering system, was unlocked too early and its deployment caused the craft to break up violently.
The subsequent nine-month FTSB investigation, in which the Federal Aviation Administration also cooperated, confirmed that finding and addressed other possible factors in the accident. The NTSB investigation included a review of cockpit video taken prior to the breakup of the craft.
With the feathering system, two tail wings in the spacecraft are repositioned to increase drag and slow the craft for descent from the upper atmosphere.
The NTSB said flight personnel were aware that unlocking the feathering system prematurely would be “catastrophic.” But no warning to that effect was included in the pilot handbook for the craft, it noted.
Personnel interviews also suggested a high pilot workload and that complexity of pilot duties might have contributed to the mishap.
“With increase complexity comes the increased possibility of an error,” NTSB member Robert Sumwalt said during a public discussion of the findings.
Additionally, the NTSB questioned whether the FAA should have issued a waiver on certain sorts of hazards analysis prior to the test flight.
British entrepreneur Richard Branson founded Virgin Galactic in 2004 as part of the Virgin Group. The Pasadena, Calif.-based company aims to take so-called space tourists on suborbital spaceflights, as well as providing launches for space science missions and small satellites.
“Although we will never forget the tragic loss of Michael Alsbury, with the investigation completed, Virgin Galactic can now focus fully on a strengthened resolve to achieve our goals,” Branson said after the NTSB released its findings. “It is important that our collective efforts and sacrifices are not in vain but serve to inspire others to make big dreams come true. Thank you to all who have helped us get this far and to all who will continue to help open space safely, for the benefit of life on Earth.”
The company has a waiting list of hundreds of passengers paying up to $250,000 for transport on suborbital flights, once such commercial flights begin.
Since last year’s fatal accident, Virgin Galactic has been building its own version of SpaceShipTwo at a plant in the Mojave. It no longer is working with Scale Composites, which is owned by Northrop Grumman.
“Virgin Galactic had begun safety reviews and a vehicle improvement program prior to the accident in preparation for the expected transition of SpaceShipTwo from Scaled Composites for the start of commercial service,” Virgin Galactic said following release of the NTSB findings. “After the flight test accident, Virgin Galactic assumed full responsibility for the completion of the flight test program and is getting ready for commercial service.”
Said Virgin Galactic CEO George Whitesides: “We remain as humbled as ever by the difficulty of our work and the challenges of space. To date, only 549 people have gone to space, and we are as passionate and resolved as ever to increase that number. The goal of people around the world to access space is as unwavering as the commitment of our team and brave pilots like Mike. We are encouraged by the progress to date with our second spaceship, and we look to the future with hope and determination.”
Scaled Composites also issued a statement:
“Our business is to design prototype, cutting-edge aircraft,” the company said. “Safety has always been a critical component of Scaled’s culture and, as the NTSB noted today, our pilots were experienced and well-trained. As part of our constant and continuing efforts to enhance our processes, we have already made changes in the wake of the accident to further enhance safety. We will continue to look for additional ways to do so.
“We extensively supported the NTSB’s investigation and appreciate all of its work to make the industry safer,” it added. “Mike Alsbury exemplified the passion that all our employees share. He and his family are always in our thoughts, and they are especially so today.”
— Carl DiOrio