Virgin Galactic's suborbital rocket glider SpaceShipTwo (SS2) could have a low wing and its carrier aircraft, White Knight II (WK2), a 43m (140ft) wingspan and four engines, chief designer Burt Rutan has said. Rutan, chief executive of Scaled Composites and a director of the Virgin Group-Scaled WK2/SS2 intellectual rights joint venture The Spaceship Company, revealed the possible design changes at the Responsibility for the Future Exploration and Development of Space Symposium, held at the University of Alabama in Tuscaloosa on 25 August. In Virgin Galactic's conceptual images, SS2 has a mid-wing, unlike its predecessor SpaceShipOne (SS1), and WK2 has two...