Sir Richard Branson has sent his condolences after one pilot died and the other was badly injured in a Virgin Galactic rocket ship crash on Friday.
The unit, which was called SpaceShipTwo, was performing a flight test with the two men on board when it exploded at 45,000ft and came down shortly after takeoff.
The wreckage remains in the Mojave Desert, California – north-east of Los Angeles – with investigations being carried out.
Sir Richard Branson immediately travelled to the California desert to be with the team
Sir Richard, who hoped to be one of the first passengers to travel to space in 2015, immediately reached out to his followers on Twitter.
"Writing this on way to Mojave to join @VirginGalactic, TSC & Scaled teams. Shocked & saddened by tragic loss," the Virgin Group founder posted.
He followed it up with: "All our thoughts are with the brave pilots & families affected by today's events in Mojave @VirginGalactic," before adding, "Space is hard – but worth it. We will persevere and move forward together."
The spacecraft crashed on Friday during a flight test
Virgin had hoped to take people to space as soon as next year, with a seat costing £156,000. Sir Richard, 64, had pledged to take the first flight while other celebrities such as Harry Styles, Justin Bieber and Ashton Kutcher are also said to have put in a request.
The company released a statement saying that the spaceship had suffered a "serious anomaly" during the test.
Local authorities confirmed that one pilot died while the other parachuted to the ground and was taken to a local hospital for treatment.
George Whitesides, CEO of Virgin Galactic, also put out a statement. "Our primary thoughts at this moment are with the crew and family, and we're doing everything we can for them now," it began, before going on to echo Sir Richard's sentiments.
"Space is hard and today was a tough day. We are going to be supporting the investigation as we figure out what happened today. We're going to get through it.
"The future rests in many ways on hard days like this, but we believe we owe it to the team, that has been working so hard on this endeavour, to understand this and to move forward. And that is what we'll do."