Sir Richard Branson has paid tribute to Michael Alsbury - the test pilot who died in Friday's accident in the Mojave Desert in California.
A memorial fund has been set up to raise money for the pilot's wife and family.
The hardest part of the tragic accident is the loss of one of SpaceShipTwo’s brave test pilots, Michael Alsbury...
Mike was an accomplished test pilot and had worked for Scaled Composites for 13 years. Beyond his skills as a pilot – including 1600 hours of flight time in research aircraft built by his colleagues at Scaled – Mike was a dear friend and inspiring colleague to the many many friends he left behind. My heart goes out to his parents, his wife and children, his sister and the rest of his family and friends.
He wished the other pilot who was injured in the incident a "speedy recovery".
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.