X-37BThe U.S. Air Force launches a second unmanned X-37B spacecraft into Earth orbit atop an Atlas V rocket. Designated USA-226, this is the second Boeing-built X-37B to reach orbit, and is the first to remain in orbit for over a year, re-entering the atmosphere and successfully conducting an automated landing in June 2012. This X-37B also features a solar panel array that is deployed from its cargo compartment, allowing it to generate constant power during its classified 15-month mission.