The privately-built and owned Space X Dragon spacecraft is one step closer to its historic docking at the International Space Station, after station astronauts successfully used the station's robotic arm to grab it.

ISS crew members will now work to attach the unmanned cargo ship to a docking port.

This is the first time a private company has launched a spacecraft to the space station, beginning a new phase in the U.S. space program after the nation retired its shuttle fleet last year.

The Dragon will remain linked with the ISS for a week so the station's crew can unload more than 500 kilograms of supplies and reload it with used equipment to be sent back to Earth.

The U.S. space agency NASA is turning to Space X and other companies to ferry supplies, and eventually astronauts, to the space station, taking over for the now-retired shuttles.

Russia, Japan, and Europe have the capability to resupply the ISS, but Russia's Soyuz spacecraft is the only vehicle currently able to transport astronauts to the outpost.