Space shuttle Discovery sits on launch pad 39A as rotating service structure rolls back at the Kennedy Space Center in Cape Canaveral, Florida 2009.[Xinhua/Reuters]
![Space shuttle Discovery sits on launch pad 39A as rotating service structure rolls back at the Kennedy Space Center in Cape Canaveral, Florida 2009.[Xinhua/Reuters]](http://images.china.cn/attachement/jpg/site1007/20090316/000bcdb95f1d0b27ea4502.jpg "Space shuttle Discovery sits on launch pad 39A as rotating service structure rolls back at the Kennedy Space Center in Cape Canaveral, Florida 2009.[Xinhua/Reuters]")