The US Air Force orbital test vehicle (OTV) X-37B has successfully de-orbited and landed, concluding an experimental test mission more than 220 days after it was launched from Cape Canaveral Air Force Station, Florida, US in April.

The Boeing-built OTV is the first US Air Force re-entry unmanned vehicle to return from space and land on its own.

The success of the inaugural mission marks the transition from the on-orbit demonstration phase to a refurbishment phase for the programme.

The X-37B programme objectives include space experimentation, risk reduction, and concept-of-operations development for reusable space vehicle technologies, which could become key enablers for future missions.

Boeing vice-president of Experimental Systems and programme director for the X-37B Paul Rusnock said the successful landing marks a new era in space exploration.

The second vehicle under the programme, X-37B, OTV-2, will be launched in 2011.