The privately funded SpaceX Dragon capsule has ended its historic flight, parachuting into the Pacific six hours after leaving the International Space Station.
Astronauts on the ISS set the world's first commercial supply ship loose after a five-day visit, using the space station's robot arm to release the vessel. The Dragon slowly backed away from the outpost, which is orbiting 250 miles (400 kilometres) above Earth, before returning home and splashing down about 500 miles west of Baja California, Mexico.
It will take a few days to carry the capsule by barge to Los Angeles. From there, it will be transported by road to the SpaceX rocket factory in Texas for unloading and inspection.
"Launch, docking, reentry and recovery successful," SpaceX's billionaire founder, Elon Musk, said in a statement provided by the California-based company. "Welcome home, baby."
Nasa has turned to American private business to take over cargo runs and, eventually, ferry astronauts to the space station, after its space shuttles were retired last year. Several companies are in the running for the human missions, with SpaceX in the lead.
President Barack Obama wants Nasa to be free of the job of making orbital deliveries so it can concentrate on sending astronauts to asteroids and Mars.
Nasa's mission control radioed praise to the six-man space station crew on Thursday: "Great work, guys." Within minutes, the capsule was outside the Nasa-controlled safety zone around the space station and under the complete jurisdiction of the SpaceX team in California.
Last week, SpaceX became the first private company to send a cargo ship to the ISS, and on Thursday it became the only supplier to return major items. The unmanned Dragon capsule has returned more than half a tonne of old space station equipment and some science samples. Because it is a test flight, Nasa did not want to load it with anything valuable.
The capsule parachuted down in the style of the US space agency's old Mercury, Gemini and Apollo spacecraft. A Dragon has returned from orbit once before, on a solo mission in December 2010.
Russia's Soyuz spacecraft, which ferry crews to and from the ISS, also parachute to Earth, but on dry land deep inside Kazakhstan. All of the government-provided cargo vessels of Russia, Europe and Japan burn up on re-entry.
Musk expects to have astronauts riding his Dragons in three or four years' time.
The next Dragon supply mission is planned for September. SpaceX's rival, Orbital Sciences Corporation, hopes to have its first test flight by the end of 2012.