The head of the US transport safety agency has said the investigation into the Virgin Galactic spacecraft crash in California's Mojave Desert could take about a year.
A National Transportation Safety Board team surveys the tail section from the crashed Virgin Galactic SpaceShipTwo. Photo: AFP
Christopher Hart said Virgin Galactic would be able conduct further test flights while the investigation took place.
SpaceShipTwo broke up in mid-air during a test flight on Friday.
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The BBC reports that one of the pilots was killed and the other injured.
Virgin chief Sir Richard Branson said he was "determined to find out what went wrong" and learn from the tragedy.
The US National Transportation Safety Board team had completed its first full day of investigation, Mr Hart said, and would be examining evidence at the scene for four to seven days.
He said the craft's debris was spread over an area measuring five miles from end to end.
He told a news conference the test flight had been "heavily documented" and his team would have to trawl through "extensive data" - which was why the full investigation could take "about 12 months or so".
However, he added than any discoveries of issues that required "immediate attention" would be communicated to Virgin Galactic.
The co-pilot who died when SpaceShipTwo disintegrated shortly after take-off was named as 39-year-old Michael Alsbury. The pilot was identified as Peter Siebold.
Scaled Composites, the company both pilots worked for, said Mr Siebold, 43, was "alert and talking with his family and doctors".
Mr Hart said his team were waiting for doctors to allow them to interview Mr Siebold.
Speaking earlier at the at the Mojave Air and Space Port, where the craft was being developed, Sir Richard said "nobody underestimates the risks involved in space travel".
Virgin Galactic had hoped to launch commercially in 2015. It has already taken more than 700 flight bookings at $250,000 each, with Sir Richard pledging to travel on the first flight.
"It's a horrible day for Virgin Galactic and for commercial space travel. It's a massive setback," Sir Richard told the BBC.
He said the company had to pick itself up, find out what went wrong and see whether they can fix it. "I'm hopeful we'll be able to overcome the problems," he added.