SpaceX's unmanned Dragon spacecraft landed softly in the Pacific Ocean at 2:51 p.m. eastern time, returning 3,700 pounds of cargo from the International Space Station.

SpaceX launched Dragon to the station in April in a mission that saw it land the first stage of its Falcon 9 rocket on a ship at sea. But the real intent was to ferry supplies to and from the orbiting laboratory. In the thimble-shaped capsule, SpaceX returned several science experiments, including the final batch of research samples from NASA astronaut Scott Kelly's nearly one-year mission in space. The science will show how humans react to long durations in space.

The Dragon also carried the spacesuit worn by astronaut Tim Kopra during a spacewalk in January. The spacewalk ended early after Kopra discovered a small water bubble inside his helmet.

The Dragon splashed down about 261 miles southwest of Long Beach, Calif.