CAPE CANAVERAL, Fla. — An unmanned space capsule carrying medical samples from the international space station splashed down in the Pacific Ocean on Sunday, completing the first official private interstellar shipment under a billion-dollar contract with NASA.
The California-based SpaceX company gently guided the Dragon into the water via parachutes at 12:22 p.m., a couple hundred miles off the Baja California coast.
Astronauts aboard the space station used a giant robot arm to release the commercial cargo ship 255 miles up. SpaceX provided updates of the journey home via Twitter, including a video of the Dragon separating from the space station.
The supply ship brought back 2,000 pounds of science experiments and old station equipment. Perhaps the most eagerly awaited cargo is 500 frozen samples of blood and urine collected by station astronauts during the past year.
The Dragon is the only delivery ship capable of returning items, now that NASA’s shuttles have been retired. Atlantis made the last shuttle haul to and from the station in July 2011.
SpaceX — formally Space Exploration Technologies Corp. — launched the capsule three weeks ago from Cape Canaveral, full of groceries, clothes, and other station supplies. Ice cream as well as fresh apples were especially appreciated by the station residents, now back up to a full crew of six.
It is the second Dragon to return from the orbiting lab; the first mission in May was a flight demo. This flight is the first of 12 deliveries under a $1.6 billion contract with NASA.
‘‘It was nice while she was on board,’’ space station commander Sunita Williams said as the Dragon backed away.
The Dragon will be retrieved from the Pacific and loaded onto a 100-foot boat that will haul it to Los Angeles. From there, it will be transported to McGregor, Texas.
The medical samples will be removed as quickly as possible, and turned over to NASA within 48 hours of splashdown, according to SpaceX. Everything else will wait for unloading in McGregor.
A Russian supply ship is set to blast off this week.