Atlas V 501

It is the first flight of the second Boeing X-37B, a United States Air Force Orbital Test Vehicle 2, which is an unmanned 5000 kg, 8.8 m-long reusable mini-spaceplane capable of autonomous re-entry and landing. The OTV-2 mission was designed to test new technologies, however the specific identity of the spaceship's payload was not revealed. The mission concluded after 468 days in orbit.