A SpaceX Dragon capsule splashed down in the Pacific Ocean on Wednesday, containing experiment results and cargo from the International Space Station (ISS).
The returned capsule is the first to make it safely back to Earth since a launch accident in June 2015 in which another Dragon capsule was destroyed.
SpaceX, founded by billionaire Elon Musk, resumed Dragon flights to the ISS last month. The capsules are the only ships that can return materials from the station.
The returned cargo contained blood, urine and saliva samples from the one-year mission of former US astronaut Scott Kelly and Russian cosmonaut Mikhail Kornienko, both of whom returned to Earth in March.
It also contained the upper torso and life-support system of the faulty spacesuit Nasa astronaut Tim Kopra wore during a January spacewalk which was cut short when water began leaking into his helmet. The return of the suit will allow engineers to investigate the source of the leak, Nasa said.
Ground controllers working from Nasa's Johnson Space Centre in Houston yesterday used the station's robot arm to remove the Dragon capsule from its berthing port and reposition it for release into space.
British astronaut Tim Peake, who has been working on the space station alongside Tim Kopra, a US astronaut, and Russian commander Yuri Malenchenko since December, then commanded the robotic arm to release the capsule as the ISS was travelling over Australia.
"Dragon spacecraft has served us well. It's good to see it departing full of science, and we wish it a safe recovery back on planet Earth," Peake radioed to Mission Control in Houston.