科學(xué)60秒:億萬富翁聚焦航天

Richard Branson has one. So do Jeff Bezos and Elon Musk. Those wealthy entrepreneurs all have spaceflight companies. Now add Microsoft billionaire Paul Allen to the list. Allen's new venture, Stratolaunch Systems, plans to build the world's biggest airplane to launch rockets from the sky. The plane will boast a wingspan longer than a football field. And it will carry rockets to wherever launch conditions are best. "Stratolaunch will build an air launch system to give us orbital access to space with greater safety, flexibility and cost effectiveness, both for cargo and manned missions." Allen at a December 13th press conference. This isn't his first foray into spaceflight, though. He previously teamed up with spacecraft designer Burt Rutan to build SpaceShipOne, the first private rocket ship to reach the edge of space. Rutan's company is building the plane for Stratolaunch as well. Rutan says that air-launching gives rockets a 5 to 10 percent performance boost. But in trying to get to orbit, every little bit helps. "It's in a world where a small advantage is actually big."