Washington - SpaceX's unmanned Dragon spacecraft left the International Space Station to return to Earth on Saturday after a month in orbit, Nasa said.
Astronauts at the orbiting lab manipulated the space station's robotic arm to detach the Dragon on time, at 09:57 (13:57 GMT), in what the US space agency called a "very clean release".
The capsule was set to splash down five and a half hours later in the Pacific Ocean, near the Mexican coast, slowed by three enormous parachutes.
The unmanned craft, which has been docked in orbit since 23 September, will be carrying back some 1 700kg of materials, including results from experiments conducted on the space station.
The SpaceX vessel is the only spacecraft currently capable of returning with cargo. Its last mission to ISS was in April.
It had delivered more than 2 200kg of cargo, including freeze-dried meals, 20 live lab mice and a 3D printer, in its fourth contracted mission to the orbiting lab.
Heavy traffic
The lab mice are the first live mammals to hitch a ride aboard a commercial cargo ship, and they are enclosed in a Nasa-made research cage for studying the effects of weightlessness on their bodies.
The 3D printer is the first of its kind to demonstrate how the technology can be used in space, even without gravity to assist the process.
The Dragon return on Saturday kicks off a week of heavy traffic to and from the orbiting science lab.
Monday evening, Orbital Sciences is scheduled to launch its unmanned Cygnus capsule from the Wallops Island space centre, on the coast of Virginia, and should arrive 2 November at ISS at the same dock that held Dragon.
And on Wednesday, a Russian cargo ship, Progress, is set to take off for ISS, taking the place of a sister Russian vessel that is to break away from the orbiting station and return to Earth on Monday.
And looking a few weeks further, three of the six ISS crew members are already preparing to leave the lab after 165 days in orbit. They are set to ride in a Russian Soyuz craft on Sunday, 9 November.
Their three replacements, a Russian and two Americans, should arrive on 23 November.