Media playback is unsupported on your device Media caption The capsule returned to Earth carrying an unusual cargo

A space capsule has returned to Earth, ending the first commercially contracted re-supply mission to the International Space Station (ISS).

The capsule was sent by the California-based company SpaceX, the first of 12 missions it will perform for US space agency Nasa.

It landed in the Pacific Ocean west of Mexico at 12:22 local time (19:22 GMT).

Nasa is looking to the private sector to assume routine transport duties to and from low-Earth orbit.

The robotic Dragon ship lifted off on 7 October, with 400kg of food, clothing, experiments and spares for the orbiting platform's six astronauts, and docked three days later.

On its return, the capsule carried broken machinery and medical samples gathered by the astronauts aboard the ISS over the course of the past year.

SpaceX's next mission is expected in January, although the company will need to satisfy Nasa before then that the cause of an engine anomaly experienced by Dragon's launch rocket during its 7 October ascent has been understood, and that corrective action has been taken.

International Space Station The International Space Station (ISS) is larger than a football pitch

The first module called Zarya was launched into orbit in 1998

It took 13 years to complete at a cost of around $100bn

There is a permanent crew of six astronauts onboard who carry out space environment research Watch NASA astronauts describe the unique view from the ISS

New destinations

Nasa has given SpaceX a $1.6bn contract to keep the ISS stocked with essentials, restoring a re-supply capability that the US lost when it retired its shuttles last year.

The terms of the contract kicked in following a successful test of Dragon's systems in May.

That demonstration saw the capsule berth with the ISS - the first commercially designed and built vehicle to do so - and then return safely to Earth.

Nasa hopes a second company can also soon begin operational cargo deliveries to the station.

The Orbital Sciences Corporation (OSC) will shortly test its new Antares rocket before undertaking its own ISS demonstration with a robotic vessel called Cygnus.

If that mission - tipped to take place next year - goes well, it will trigger a $1.9bn contract for Orbital.

Nasa's aim is eventually to put astronaut transport in the hands of the private sector too.

SpaceX says it is just a few years away from being able to provide an astronaut "taxi" service.

Nasa's policy of outsourcing its cargo and crew transport needs is intended to find savings that can be ploughed back into building a rocket and capsule system capable of taking humans to more challenging destinations.