Virgin Galactic continues to rack-up the milestones in its quest to get sub-orbital space tourism up and running, this time with its inaugural “captive carry” test flight. VSS Enterprise (formerly known as SpaceShipTwo before it was renamed at its unveiling in December) spent 2 hours 54 minutes attached to the WhiteKnightTwo carrier aircraft in the skies above the Mojave Air and Spaceport, California. The spaceship will be cut loose from its carrier for independent glide and then powered flight testing as the program continues through 2010 and 2011, then it's all-aboard for paying customers.

Both VSS Enterprise and the WK2 mothership (christened EVE) were developed by Ansari X prize Scaled Composites.

“This is a momentous day for the Scaled and Virgin Teams", said Scaled founder Burt Rutan. "The captive carry flight signifies the start of what we believe will be extremely exciting and successful spaceship flight test program.”

The captive carry test flight achieved an altitude of 45,000 ft (13716 metres), just shy of the 50,000 ft release height planned for when actual flights get underway.

When the US$200K ticket-holders do climb on board, VSS Enterprise will hit Mach 4 after the release and cross the Kármán line (the internationally defined boundary between Earth and space of 100 km) to reach a maximum height of 361,000 ft (110 km) before gliding home.

Virgin Galactic says it has already taken around US$45m in deposits for spaceflight reservations from over 330 people would-be astronauts.