Image: SpaceX's Dragon capsule is pictured after splashing down approximately 250 miles off the coast of southern California

NASA's first commercial cargo flight ended with a splash on Sunday, when the SpaceX Dragon capsule landed after a landmark mission to the International Space Station.

The unmanned Dragon space capsule, built by the U.S. company Space Exploration Technologies (SpaceX), splashed down into the Pacific Ocean off the coast of Southern California at 3:22 p.m. EDT (1922 GMT), ending a three-week visit to the orbiting laboratory.

Dragon began its descent with a de-orbit burn at 2:28 p.m. EDT (1828 GMT), after departing the station at 9:29 a.m. EDT (1329 GMT) as both spacecraft sailed 255 miles (410 kilometers) above Burma. The station's crew used the outpost's robotic arm to release the spacecraft.

"It was nice while she was on board. We tamed her [and] took her home," space station commander Sunita Williams of NASA radioed Mission Control in Houston as the Dragon capsule departed. "Literally and figuratively, there are pieces of us on that spacecraft going home to Earth."

The Dragon capsule is returning hundreds of astronaut blood and urine samples from the space station amid the 1,673 pounds (758 kilograms) of experiments and gear loaded on board. Some of those samples have been waiting for more than a year. NASA's final space shuttle mission landed in July 2011, leaving the agency without a way to return big cargo deliveries to Earth until Dragon's flight.

Read more at NBC News.