The unmanned SpaceX capsule made a safe splashdown in the Pacific Sunday after successfully delivering its first commercial payload to the International Space Station.

The capsule parachuted into the water at 1922 GMT after an 18-day mission to resupply the station and was now being recovered by a team of divers, US-based SpaceX said in a brief statement on its website.

The mission -- the first of 12 planned trips in SpaceX's $1.6 billion contract with US space agency NASA -- is a milestone for American efforts to privatize the space industry, aimed at reducing costs and spreading them among a wider group than governments alone.

The capsule delivered about 1,000 pounds (450 kilograms) of cargo to the space station and is taking home 1,670 pounds (758 kilograms) of supplies, hardware and scientific tests and results.

Earlier Sunday, an astronaut aboard the floating laboratory detached and released the capsule using a robotic arm, kicking off its return to Earth.

Owned by billionaire Paypal co-founder Elon Musk, SpaceX is one of several private firms working with the US space agency to send flights to and from the ISS, but SpaceX is the first to become operational.

The next SpaceX flight is scheduled for early January 2013.

NASA has been relying on Russian spacecraft for the last year, after retiring its fleet of shuttles -- but the Soyuz craft does not have room for cargo on the return flight.

SpaceX's May mission -- a nearly flawless nine-day test flight to deliver cargo to the $100 billion orbiting station -- marked the first time a commercial outfit had sent its own capsule there and back.

SpaceX says it has 50 launches planned -- both NASA missions and commercial flights -- representing about $4 billion in contracts.

So far, SpaceX has only sent unmanned flights into orbit, but the company aims to send a manned flight within the next three or four years. It is under a separate contract with NASA to refine the capsule so that it can carry a crew.

NASA also has a $1.9 billion resupply contract for the station with Orbital Sciences Corporation which will run its first test flight in the next few months at a base in Virginia.