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.
Investigators looking into the fatal test flight of Virgin Galactic's SpaceShipTwo aircraft say a "feathering" system deployed too early.
ITV News' Science Correspondent Alok Jha explains how it works:
It is not yet clear why the system deployed, or whether this caused the aircraft to break up in mid-air. These are questions for the investigation which is due to last up to a year.
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.