MOJAVE AIR AND SPACE PORT -- In a feat that is expected to move Virgin Galactic one giant step closer to offering tourist flights to suborbital space, the commercial space company this morning launched the first powered flight of its spaceplane here in the Mojave Desert in eastern Kern County. SpaceShipTwo, tethered to its mother ship WhiteKnightTwo, lifted off at just after 7 a.m., just like a conventional airplane.