REUTERS/Lucy Nicholson
A piece of SpaceShipTwo recovered from the crash in October 2014.
The nine-month investigation, led by the National Transportation Safety Board (NTSB), concluded the ship's co-pilot repositioned the tail wings too early, causing SpaceShipTwo to break apart during a test flight over the Mojave desert.
SpaceShipTwo's tail wings are equipped with a "feathering system." When activated it repositions the wings upward, slowing down the craft and steadying its descent toward the Earth.
But according to the NTSB report, co-pilot Michael Alsbury (who died in the crash) deployed the system when SpaceShipTwo reached Mach 0.92 instead of the correct speed - Mach 1.4. Pilot Peter Siebold survived the 10-mile fall, but the incident seriously injured him.
During a public hearing on July 28, NTSB investigator Katherine Wilson said Alsbury may have deployed the system early to avoid having to abort the flight. If the feathering system isn't deployed by Mach 1.8, the flight must be aborted. Alsbury had not performed a flight like this in more than a year - and that may contributed to his decision to unlock the system early, NTSB managing director Tom Zoeller said during the hearing.
"The co-pilot was experiencing a high workload as a result of recalling tasks from memory while performing under time pressure," Zoeller said.
The investigation also alleges that Scaled Composites did not anticipate a pilot unlocking the feathering system early. There wasn't even a backup safety mechanism in place for the scenario, according to the NTSB.
The NTSB gave a long list of safety recommendations for both Scaled Composites and Virgin Galactic. The list included a modification to the feather lock system to prevent it from being locked or unlocked during dangerous flight phases. It also recommended a new checklist for pilots to go through before they unlock the feathering system. Virgin Galactic said that it proactively made both changes to SpaceShipTwo after the accident, yet before the NTSB's report came out.
In November last year, Virgin Galactic CEO Sir Richard Branson said the crash may have ended his dream of commercial space tourism. The company assumed full responsibility for the accident, and Branson said Virgin Galactic would only push forward if it could identify what went wrong and overcome it.
Since the accident, Virgin Galactic parted ways with Scaled Composites. It will now be using its own manufacturing company and hiring its own test pilots. So it looks like Virgin Galactic is back on track.
"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 in a video statement.
About 700 people have already paid $250,000 to reserve a spot on SpaceShipTwo. The plane is designed to fly 62 miles above Earth's surface, where future passengers will experience weightlessness and get a glimpse of Earth from space.
Watch Branson's full statement below: