On June 16th the Air Force’s X-37B unmanned spaceplane landed at Vandenberg AFB, California.

The X-37B Orbital Test Vehicle, one of two such vehicles, spent 469 days in orbit to conduct on-orbit experiments, primarily checkout of the vehicle itself…

Managed by the Air Force Rapid Capabilities Office, the X-37B program performs risk reduction, experimentation, and concept of operations development for reusable space vehicle technologies. The X-37B mission is the longest space mission only after the NASA Discovery shuttle program.

The X-37 has been a subject of much speculation over its unusual mission length and undisclosed purposes.