A capsule launched by U.S. aerospace manufacturer SpaceX successfully docked with the International Space Station on Sunday morning, becoming the first manned commercial spacecraft to do so.

The Crew Dragon space capsule lifted off from Kennedy Space Center in Florida on Saturday afternoon and arrived at the ISS as scheduled approximately 19 hours later.

The launch marked the end of a nine-year period in which NASA astronauts had not departed for the ISS from U.S. soil.

 Artist's concept of Space X Crew Dragon[Image supplied by Space X)

While SpaceX has been delivering cargo to and from the ISS since 2012, it is the first time that it used its spacecraft to transport humans to the orbiting laboratory.

The mission is a key milestone on the way to NASA certifying the Crew Dragon for operational, long-duration missions to the ISS.

Following the docking, the two astronauts -- Douglas Hurley, 53, and Robert Behnken, 49 -- will perform tests on the Crew Dragon in addition to conducting research and other tasks alongside ISS crew, according to the U.S. National Aeronautics and Space Administration.

If the mission turns out to be a success, the crew for the next flight, possibly in late August, will include Japanese astronaut Soichi Noguchi, 55.

SpaceX, officially known as Space Exploration Technologies Corp. and founded by Tesla Inc. billionaire Elon Musk, is working with NASA to develop a successor to the Space Shuttle transportation system that was in service for 30 years through 2011.

NASA has also partnered with Boeing Co. which has developed its own capsule. Named the Starliner, it failed to reach the ISS in an unmanned test in December last year after experiencing trouble with its flight-control system.

NASA has invested in private companies in hopes of creating a safe, reliable and cost-effective means of transporting humans to the ISS.