A SpaceX Dragon capsule headed back to Earth on Wednesday filled with more than 3,700 pounds of experiment results and cargo from the International Space Station. (Reuters)

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.