US space firm SpaceX on Friday successfully landed the first stage of its Falcon 9 rocket on a droneship in the Atlantic Ocean after launching a cargo ship to the International Space Station.

"The 1st stage of the Falcon 9 just landed on our Of Course I Still Love You droneship," the California-based company said via Twitter.

It's the first time SpaceX has been able to stick a landing on a droneship after four previous such attempts ended in failure. It also achieved one successful soft landing on a land-based pad at Cape Canaveral in December last year.