The investigation into the Virgin Galactic’s SpaceShipTwo crash in California’s Mojave Desert could take about a year, the head of the US National Transportation Safety Board (NTSB) has said.

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 October 31.

One of the pilots was killed and the other injured.

Virgin Group founder Sir Richard Branson says he is “determined to find out what went wrong” and learn from the tragedy.

The NTSB team had completed its first full day of investigation, Christopher 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.

Christopher Hart 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”.

Peter Siebold, right, survived the incident but his co-pilot, Michael Alsbury, died

He said there were six cameras on the craft itself, with another three on its launcher, an aircraft called WhiteKnightTwo, although it was unclear whether SpaceShipTwo’s cameras had been found.

The co-pilot who died when SpaceShipTwo disintegrated shortly after take-off was named as 39-year-old Michael Alsbury.

The pilot who survived was identified as Peter Siebold. Scaled Composites, the company both pilots worked for, said Peter Siebold, 43, was “alert and talking with his family and doctors”.

Christopher Hart said his team was waiting for doctors to allow them to interview Peter Siebold.

Speaking earlier at the at the Mojave Air and Space Port, where the craft was being developed, Richard Branson 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.

The spacecraft was flying its first test flight for nine months when it crashed near the town of Bakersfield.

Virgin Galactic said SpaceShipTwo had experienced “a serious anomaly” after it separated from WhiteKnightTwo.

SpaceShipTwo craft was using a new type of rocket fuel never before used in flight, although officials said it had undergone extensive ground testing.

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