Above, photograph of Virgin Galactic's Richard Branson and Scaled Composites' Burt Rutan in front of a model; below thumbnail is a rendering of the WhiteKnight At the American Museum of Natural History yesterday, British entrepreneur Richard Branson unveiled the aircraft for his Virgin Galactic space travel venture and promised, "2008 is really going to be the year of the spaceship." Scaled Composites (which designed the spaceplane, SpaceShipOne, that had a human-piloted space flight a......