The U.S. Air Force on Thursday launched a space plane, an unmanned spacecraft designed to fly in low orbit for as long as nine months. The plane, code-named X-37B, has blasted off with a rocket from Florida's Cape Canaveral Air Force Station. Its mission will be controlled by Air Force Space Command. The spacecraft's mission remains classified. It will carry out undisclosed tests and release payload into space. It is slated to land at Vandenberg Air Force Base in California.