The US Air Force launched the X-37B space plane on Thursday on a classified mission, leading some to speculate on its intended future use. The options range from a laser weapon platform to a stop gap replacement for the retiring space shuttle fleet.

As part of this initial mission, the Air Force will evaluate the X-37B's guidance, navigation, thermal protection, and unmanned operations in orbit, re-entry, and landing. It will function in space like other satellites, with operators on Earth monitoring its travels. Eventually, the Air Force will tell the space plane to head home. "Upon being given the command to return to Earth, the X-37B will automatically descend through the atmosphere and land on the designated runway. There is no one on the ground with a joystick flying it," said Lt. Col. Troy Giese, the X-37B systems program director, in a statement.

Though the 11,000-pound vehicle--about 29 feet long, with a wingspan of just under 15 feet--is designed to stay in orbit for 270 days, the exact duration of its first flight hasn't been revealed. Upon completing its first mission, the Boeing-built X-37B is due to touch down at Vandenberg Air Force Base in California. The resemblance to the space shuttle isn't surprising. The X-37, in fact, was originally a NASA program, with roots in the space agency's lifting-body research, that ran from 1999 to 2004. That effort was intended to help in the design and development of a new Orbital Space Plane that would serve as a transport and rescue vehicle for crews at the International Space Station.