The U.S. military has launched an unmanned spacecraft designed to fly in low orbit for as long as nine months. The plane X-37B, blasted off with a rocket last night from Florida's Cape Canaveral Air Force Station. Its mission will be controlled by Air Force Space Command. The military vehicle is unpiloted and will carry out the first autonomous re-entry and landing in the history of the US space programme. The spacecraft can return experiments to Earth for inspection and analysis. The re-usable spaceplane is about one quarter the size of the shuttle, with a large engine mounted at the rear of the ship for orbit changing. It is powered by a solar array and lithium-ion batteries. The precise objectives and cost of the programme are secret.