(CNN) -- The surviving co-pilot in the Virgin Galactic SpaceShipTwo disaster is "alert" and speaking, the company that partnered with Virgin on the test flight program said Sunday.
But while Peter Siebold appears to be recovering after the accident, not much is known about what caused the spacecraft's apparent in-flight breakup. At least not yet.
A team of 13 to 15 investigators from the National Transportation Safety Board will be on site in the Mojave Desert for about a week. But analyzing the data from the test aircraft will take much longer.
All told, it may be 12 months before the investigation is complete, the agency's acting Chairman Christopher Hart said Saturday night.
"Because it was a test flight, it was heavily documented," Hart said. For instance, there were six cameras on the test aircraft alone.
Such an abundance of data is a good thing, he said.
"We may have lots of evidence that will help us with the investigative process, and we appreciate that."
For now, though, answers are in short supply.
SpaceShipTwo disintegrated Friday, 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, and about 20 miles northeast, of Mojave, California.
It left a debris field that spanned 5 miles.
While the NTSB hasn't determined what broke the test aircraft apart, "when wreckage is dispersed like that, it indicates the likelihood of in-flight breakup," Hart said.
There were two pilots on board at the time.
Co-pilot Michael Tyner Alsbury, 39, died. A memorial fund has been set up for him.
Siebold, 43, parachuted to the ground and survived with moderate injuries.
Scaled Composites, a Mojave-based company that was also involved in the test flight program, released a statement saying Siebold was alert and that the company was supporting the agencies investigating the crash.
"The Scaled Composites family lost a respected and devoted colleague yesterday, Michael Alsbury, who was the co-pilot for the test flight of SpaceShipTwo," it said. "Peter Siebold, the director of flight operations at Scaled Composites, was piloting SpaceShipTwo. He is alert and talking with his family and doctors. We remain focused on supporting the families of the two pilots and all of our employees, as well as the agencies investigating the accident. We ask at this time that everyone please respect the privacy of the families."
NTSB investigators have yet to interview Siebold.
"We have not because doctors did not recommend we do an interview at this stage," Hart said.
'We're going to learn'
Virgin Group founder Richard Branson said Sunday he didn't personally know Alsbury, but had the privilege of knowing Siebold.
"Mike was a dear friend and inspiring colleague to the many, many friends he left behind. My heart goes out to his parents, his wife and children, his sister and the rest of his family and friends," he said about Alsbury.
He wished Siebold a speedy recovery.
On Saturday, Branson said that the company is "determined to find out what went wrong."
The company, he said, will not "push on blindly."
"To do so would be an insult to all those affected by this tragedy," he said. "We're going to learn from what went wrong, discover how we can improve safety and performance and then move forward together."
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.
Years of flight experience
The two test pilots had both had a great deal of flight experience.
Alsbury worked at Scaled Composites and logged more than 1,600 hours as test pilot and test engineer in Scaled aircraft.
Siebold had worked for Scaled Composites since 1996 and had 17 years and more than 2,000 hours of flight experience.
Both had degrees in aeronautical engineering from California Polytechnic State University in San Luis Obispo, California.
As for the program itself, 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.
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.