Secret mission accomplished: America's secret space plane to land after a YEAR in orbit - and no one knows what it did up there.....

The U.S Air Force’s highly secret unmanned space plane will land in June - ending a year-long mission in orbit.

The experimental Boeing X37-B has been circling Earth at 17,000 miles per hour and was due to land in California in December. It is now expected to land in mid to late June.

At launch, the space plane was accompanied by staff in biohazard suits, leading to speculation that there were radioactive components on board.