The space shuttle Atlantis has separated from the International Space Station at the start of its final return to earth as the US shuttle programme comes to an end. The shuttle astronauts exchanged embraces and leaving gifts with the station crew before closing the hatch. Atlantis ended its 13-day mission and is scheduled to land at the Kennedy Space Center in Florida on Thursday. Atlantis, the fourth shuttle in NASA's fleet, first flew into space in October 1985.