Mysterious US spaceplane returns to Earth

  • 18 October 2014
Secret plane Image copyright AP

An unmanned US plane on a top-secret, two-year mission to space has returned to Earth and landed in California.

The aircraft, which looks like a miniature space shuttle, is known as the Orbital Test Vehicle or X-37B and spent 674 days in orbit around the planet.

It touched down at Vandenberg Air Force Base on Friday morning.

Air Force officials have only told US media the aircraft performs "risk reduction, experimentation and concept-of-operations development for reusable space vehicle technologies".

This has led to different theories about what it was used for.

Image copyright AP
Image caption A fourth X-37B mission is planned for 2015
Image copyright Reuters
Image caption The secret spaceplane is built by manufacturer Boeing