Sir Richard Branson has vowed to continue his space tourism venture despite the fatal crash of one of his craft in the California desert.
One pilot died and the other was badly injured when Virgin Galactic's SpaceShipTwo craft exploded on Friday.
The founder of the Virgin Group said he was 'shocked and saddened' but insisted he would 'persevere' with space travel.
The craft was flying a manned test when it experienced what the company described as 'a serious anomaly'.
Sir Richard said Virgin Galactic would co-operate fully with the authorities involved in the investigation.
Officials with the US National Transportation Safety Board will begin their investigation on Saturday morning, which will probably take several days.
'Space is hard'
In a blog post, Mr Branson said everyone involved in the project was 'deeply saddened'.
'All our thoughts are with the families of everyone affected by this tragic event,' he wrote.
He said that he was flying to California immediately, describing it as 'one of the most difficult trips I have ever had to make'.
'Space is hard - but worth it. We will persevere and move forward together,' he added.
George Whitesides, chief executive of Virgin Galactic, said: 'Space is hard and today was a tough day.
'The future rests in many ways on hard days like this, but we believe we owe it to the team to understand this and to move forward. And that is what we'll do.'
Wreckage from the crash was scattered across the Mojave desert, north-east of Los Angeles. Police secured the site amid fears that some of the debris could be explosive.
Both pilots were employed by Scaled Composites, the company that designed the craft. One was pronounced dead at the scene while the other was transported to a local hospital in an unknown condition.
The spacecraft had been carried into the air by an aircraft known as WhiteKnightTwo before being released at an altitude of 45,000 feet (13,700m) for a test of its rocket engine. It crashed shortly afterwards.
In a statement, Virgin Galactic said the 'vehicle suffered a serious anomaly resulting in the loss of SpaceShipTwo'.
The WhiteKnightTwo aircraft landed safely, the statement added.
Analysis: David Shukman, BBC science editor
Even as details emerge of what went wrong, this is clearly a massive setback to a company hoping to pioneer a new industry of space tourism. Confidence is everything and this will not encourage the long list of celebrity and millionaire customers waiting for their first flight.
An innovative design for a spacecraft combined with a new type of rocket motor to make the development challenge exceptionally hard. Despite an endless series of delays to its spacecraft, Virgin Galactic has over the years managed to maintain some very optimistic public relations and positive media coverage.
I interviewed Sir Richard Branson when he first announced the venture, and his enthusiasm and determination were undoubted. But his most recent promises of launching the first passenger trip by the end of this year had already started to look unrealistic some months ago.
Will crash set back space tourism?
Today's accident will delay plans even further. Space is never easy, and making it routine is even harder.
The head of the US space agency Nasa, Charles Bolden, voiced his shock at the crash, saying: 'The pain of this tragedy will be felt by all the men and women who have devoted their lives to exploration.
'Space flight is incredibly difficult, and we commend the passion of all in the space community who take on risk to push the boundaries of human achievement.'
It was the second accident this week involving a commercial space company in the US.
On Tuesday, an unmanned supply rocket called Antares exploded shortly after its launch from Virginia. It was carrying cargo to the International Space Station.
Virgin Galactic has been a frontrunner in the nascent space tourism industry, and Sir Richard said earlier in October he expected to see the craft make it to sub-orbital space within a few months.
More than 800 people have already paid or put down deposits for a trip on SpaceShipTwo, at a cost of about $200,000 (£125,000) per person, including actor Leonardo DiCaprio.