Discovery, the world's most travelled spaceship, left the International Space Station for the last time on Monday. It received a poignant send-off from the dozen of orbiting astronauts.

ISS skipper Scott Kelly rang the ship's bell in true naval tradition, as the shuttle backed away on the final leg of its final journey.

Discovery delivered a new storage compartment, an equipment platform, and the first humanoid robot in space. The 27 year old spacecraft, known as "the old lady of the fleet", is due back on Earth on Wednesday.

After touchdown, it will be retired and put on display in the US Smithsonian Institute.