The investigation into what caused the Virgin Galactic test flight to crash could take as long as 12 months, lead investigator Chris Hart has said.
Mr Hart, who is acting head of the National Transportation Safety Board, also told reporters that his team would interview injured co-pilot Peter Siebold when he was ready.
Sir Richard Branson has said he "will not push on blindly" to achieve commercial space travel but wants to "learn from what went wrong" in the fatal crash of Virgin Galactic's test rocket plane.
"I truly believe humanity's greatest achievements come from the greatest pain," he said at a news conference in Mojave, California.
Sir Richard said the past 24 hours had been a "very tough time for everybody who works at Virgin Galactic" and thanked tributes from around the globe, including from Nasa, Canadian astronaut Chris Hadfield and the International Space Station.
Faced with a five-mile debris trail and masses of technical data, the team investigating the crash of SpaceShipTwo have their work cut out.
The loss is a tragedy for this small tight-knit team that dreams of making the trip into space accessible to travellers not just astronauts.