NTSB confirms premature unlocking of feather system prior to SpaceShipTwo crash

The U.S. National Transportation Safety Board (NTSB) says that the feather system was prematurely unlocked at or near Mach 1.0 on Virgin Galactic's SpaceShipTwo and was immediately followed by the craft's disintegration and crash, killing the copilot and injuring the pilot.

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The U.S. National Transportation Safety Board (NTSB) reported on Nov. 3 that the feather system was prematurely unlocked at or near Mach 1.0 on Virgin Galactic's SpaceShipTwo and was immediately followed by the craft's disintegration and crash during a test flight on Oct. 31, killing the copilot and critcally injuring the pilot.

At a press briefing on Nov. 3, acting NTSB chairman Christopher Hart reported that SpaceShipTwo released from MotherShipTwo at 10:07:19 a.m. PST on Oct. 31. At 10:07:21 the rocket on SpaceShipTwo fired. The craft reached Mach 0.94 at 10:07:29, and Mach 1.02 at 10:07:31, at which point the feather system transitioned from a locked to an unlocked position and began to deploy. At 10:07:34, the data and video feed was lost, apparently indicating the destruction of the craft.

The feather system was moved from the locked to unlocked position by the copilot, who was in the righthand seat. Hart added that the feather system, according to flight instructions, was supposed to be unlocked when the craft reached Mach 1.4. Deployment of the feather system occurs in two steps: Unlocking, followed by deployment, both of which are performed in the cockpit by the pilots. Hart said that it appears that an "uncommanded feathering" occurred prior to the crash, which means that after the feather was unlocked, the feather was deployed without pilot action — possibly by aerodynamic forces. 

"What we know is that after it was unlocked, the feathers moved into the deployed position, and two seconds later we saw disintegration," Hart said. "That's the fact. We will find out the analysis as part of the investigation."

NTSB also reported that parts of SpaceShipTwo were found primarily over a 5-mile stretch in the California desert, however Hart said the agency discovered some smaller debris as far as 35 miles away — possibly pushed further by the prevailing winds. The fuel tanks and engine were found intact and showed no signs of breach or malfunction. The complete NTSB investigation could take 12 months to complete, Hart said.

Virgin Galactic, for its part, said on its website, "While this has been a tragic setback, we are moving forward and will do so deliberately and with determination. We are continuing to build the second SpaceShipTwo (serial number two), which is currently about 65 percent complete and we will continue to advance our mission over the coming weeks and months. With the guidance of the NTSB and the assurance of a safe path forward, we intend to move ahead with our testing program and have not lost sight of our mission to make space accessible for all. We owe it to all of those who have risked and given so much to stay the course and deliver on the promise of creating the first commercial spaceline."