(CNN) -- It could take a year to figure out what caused the Virgin Galactic SpaceShipTwo to disintegrate in the sky, killing one co-pilot and raising questions about the future of commercial space flight.
But two new clues have emerged about what went wrong before the Friday disaster. And both involve the spacecraft's "feathering," a process used to stabilize and slow the spacecraft down toward Earth.
During feathering, two pieces on the back of the vehicle -- the "feathers" -- lift up perpendicular to the spaceship, making the vehicle look like it's arching its back as it descends.
But on Friday, "the feather lock-unlock lever was moved by the co-pilot from the locked position to the unlocked position" prematurely, the National Transportation Safety Board said Sunday night.
On top of that, the feathers aren't supposed to move until a separate feathering handle is activated. No one adjusted that handle; yet the feathers were still deployed, NTSB acting Chairman Christopher Hart said.
But Hart stressed that it was unclear whether pilot error, mechanical problems or another possibility caused the spacecraft to break apart in the air.
"We are still a long way from finding a cause," Hart said. "We are months and months away."
Despite a debris field spanning 5 miles, investigators have found almost all the parts of the spacecraft needed for the investigation, Hart said.
Veteran pilot killed
The accident killed co-pilot Michael Tyner Alsbury. He worked at Scaled Composites, the company that partnered with Virgin on the test flight program, and logged more than 1,600 hours as a test pilot and test engineer in Scaled aircraft.
A memorial fund has been set up for his family.
"Mike was a dear friend and inspiring colleague to the many, many friends he left behind," Virgin Group founder Richard Branson said Sunday. "My heart goes out to his parents, his wife and children, his sister and the rest of his family and friends."
Co-pilot alert and talking
The surviving co-pilot, Peter Siebold, parachuted to the ground and survived with moderate injuries. He was alert and speaking with family and doctors, Scaled Composites said Sunday. Siebold is the company's director of flight operations.
"We remain focused on supporting the families of the two pilots and all of our employees, as well as the agencies investigating the accident," Scaled Composites said.
NTSB investigators have yet to interview Siebold. "We have not because doctors did not recommend we do an interview at this stage," Hart said.
Crumbling in the air
SpaceShipTwo disintegrated just two minutes after the space plane separated from the jet-powered aircraft that carried it aloft.
At the time, it was about 45,000 feet above the ground and about 20 miles northeast of Mojave, California.
A team of 13 to 15 investigators from the National Transportation Safety Board will be in the Mojave Desert for about a week. But analyzing the data from the test aircraft will take much longer.
'We will persevere'
Branson said his company is "determined to find out what went wrong."
"We understand that everyone is anxious to understand what happened on Friday; certainly no one wants to know more than we do," Virgin Galactic said in a statement Sunday.
"However, as we have made clear, Virgin Galactic is not in a position to comment on the incident itself or the test flight. The National Transportation Safety Board (NTSB) is in charge of the investigation and we are cooperating fully with their work."
When asked about the future of Virgin Galactic, Branson said the company's goal is still putting people safely into space.
"I think millions of people in the world would love one day to have the chance to go to space, and this is the start of a long program," he said.
SpaceShipTwo had flown 55 times, 35 times on its own, Branson said in a statement. WhiteKnightTwo, the jet-powered "mothership" charged with transporting SpaceShipTwo to altitude, has flown 173 times, Branson said.
"We've always known that the road to space is extremely difficult -- and that every new transportation system has to deal with bad days early in their history," Branson said. "Space is hard -- but worth it. We will persevere and move forward together."
Future of the program
For years, Virgin Galactic has planned to sell trips in which SpaceShipTwo would transport passengers about 62 miles above Earth -- the beginning of outer space -- and let them experience a few minutes of weightlessness before returning to the ground.
It's unclear what the failure of the space plane will mean for the program. Virgin Galactic planned to send paying customers on SpaceShipTwo as early as next year.
The company released a statement late Sunday.
"At Virgin Galactic, we are dedicated to opening the space frontier, while keeping safety as our 'North Star'. This has guided every decision we have made over the past decade, and any suggestion to the contrary is categorically untrue," it said.
"Now is not the time for speculation. Now is the time to focus on all those affected by this tragic accident and to work with the experts at the NTSB, to get to the bottom of what happened on that tragic day, and to learn from it so that we can move forward safely with this important mission."
Virgin has sold more than 700 tickets, each costing more than $250,000, for future flights. Several celebrities have already signed up, including Justin Bieber, Ashton Kutcher, Leonardo DiCaprio and Stephen Hawking.
CNN's Ric Ward, Rosalina Nieves, Mayra Cuevas, Mike Ahlers and Sonya Hamasaki contributed to this report.