Commercial space firm Virgin Galactic has unveiled the plane which will launch its SpaceShipTwo orbital craft.

The twin-fuselage WhiteKnightTwo will carry the new spacecraft to heights of some 48,000ft before its launch into orbit.

The first WhiteKnightTwo craft has been christened 'Mothership Eve' in a tribute to Virgin founder Sir Richard Branson's mother.

"The rollout of WhiteKnightTwo takes the Virgin Galactic vision to the next level and continues to provide evidence that this most ambitious of projects is making tremendous progress towards our goal of safe commercial operation," said Branson.

"Virgin Galactic is central to our ambition to become the world's leading group in the operation of energy and environmentally efficient transportation, in the air, on the ground and in space."

Mothership Eve has a wingspan of some 140ft, the largest ever for a carbon composite aircraft.

The craft will have to wait some time before her maiden commercial flight with the spacecraft. SpaceShipTwo is not scheduled to be completed until at least 2009 and it will only begin ground testing later this year.

In addition to the SpaceShipTwo duties, Mothership Eve could also serve as a launch point for other small spacecraft and satellites.

The plane is capable of carrying a maximum weight of 30 per cent more than a fully-loaded SpaceShipTwo craft.