A privately owned cargo ship left the International Space Station with a full science load Tuesday and aimed for a splashdown in the Pacific.
Astronauts released the unmanned SpaceX capsule, named Dragon, from the end of the space station's giant robot arm. The parting occurred 250 miles over the South Pacific and was a poignant moment for the three space station residents, who had helped to snare the Dragon three weeks earlier.
"Sad to see the Dragon go," astronaut Thomas Marshburn told Mission Control. "Performed her job beautifully. Heading back to her lair. Wish her all the best for the splashdown today."
The Dragon was due to splash down off the Baja California coast 5½ hours after its space station departure. It will be transported by ship to Los Angeles and then by truck to the SpaceX company's plant in McGregor, Texas.
Within hours, NASA will retrieve the science samples meticulously collected over the weeks and months by space station astronauts, as well as experiments that flew up with Dragon, such as flowering weeds and mouse stem cells. Old space station equipment and other items will be removed by SpaceX in McGregor. In all, more than 1 ton of gear was loaded into the capsule.
Dragon's return to Earth was delayed one day by bad weather in the splashdown zone.
The California-based SpaceX company launched the Dragon from Cape Canaveral, Fla., at the beginning of March. Mechanical trouble caused a one-day postponement in Dragon's arrival at the space station. SpaceX flight controllers at company headquarters in Hawthorne, Calif., managed to fix the problem within hours.
SpaceX - Space Exploration Technologies Corp. - is run by billionaire Elon Musk, who made his fortune as a co-creator of PayPal. He also owns the electric car maker Tesla Motors.
NASA is paying SpaceX to resupply the space station. This was the second flight of a Dragon to the orbiting outpost under the $1.6 billion contract, and the third delivery mission altogether for SpaceX. The next flight is slated for late fall.
A competitor, Orbital Sciences Corp. of Dulles, Va., plans a test flight of its Antares rocket and a dummy payload next month. That launch will be conducted from Wallops Island, Va.
Russia, Japan and Europe also periodically send up supplies, but SpaceX has the only craft capable of returning goods. All the others burn up upon re-entry.
Three astronauts are aboard the space station right now. They will be joined by three more following Thursday's Soyuz launch from Kazakhstan.
With its space shuttles now museum pieces, NASA is paying Russia to launch U.S. astronauts until SpaceX or another American company comes up with spaceships than can safely fly crews. Musk anticipates that happening by 2015.