Moments before Virgin Galactic's Space Ship Two broke up over the Mojave Desert, investigators said the co-pilot prematurely deployed the spacecraft's descent system.
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While a cause of the crash has not yet been determined, National Transportation Safety Board Acting Chairman Christopher Hart said in a briefing on Sunday night that investigators found the feathering system that slows the spacecraft's descent was deployed before it reached the appropriate speed.
Hart said the two-step system was unlocked by the co-pilot and that the second step to deploy it happened without receiving a command from the pilot.
"We are not edging toward anything, we're not ruling anything out," Hart said. "We are looking at all these issues to determine the root cause of this accident."
It could be as long as a year before federal investigators have any answers about what caused the Virgin Galactic spacecraft to crash.
Among the causes being explored are pilot error, mechanical failure and the the design of the spacecraft, Hart said.
The NTSB is expected to hold a news conference today, where they are expected to reveal more details.
Since SpaceShipTwo was a test flight, there was a great deal of data recorded by Virgin Galactic and its partner, Scaled Composites, which investigators will be able to analyze as a part of their investigation.
The 60-foot spacecraft broke apart after being released from a carrier aircraft at high altitude.
"The wreckage is located in a large area, oriented northeast to southwest, about five miles from end to end," Hart said. "And when the wreckage is dispersed like that, that indicates the likelihood of in-flight break-up."
Co-pilot Michael Tyner Alsbury, 39, of Tehachapi, Calif., was found dead inside the wreckage.
He was involved in the flight testing of nine different manned aircraft and co-piloted SpaceShipTwo when it broke the sound barrier during its first powered flight last year. He was also sitting in the co-pilot's seat when the craft first dropped in 2010 from its carrier aircraft several miles above the Earth for an unpowered glide test.
Peter Siebold, director of flight operations for Scaled Composites and the pilot of SpaceShipTwo, was able to parachute to safety and was taken to a hospital for treatment.
Sir Richard Branson, founder of the Virgin Group, said "safety has guided every decision" Virgin Galactic has made over the past decade and vowed that the company's dream of commercial space travel would continue.
Branson said that anyone who signed up for a chance at space travel, which costs as much as $250,000 per person, can have their money refunded.
The Associated Press contributed to this report.