A ball-shaped artificial intelligence robot nicknamed the "flying brain" because it is trained to follow and interact with a German astronaut, blasted off Friday toward the International Space Station aboard SpaceX's Dragon cargo ship.

A new, spare hand for the station's robotic arm, an experiment to measure plant stress in space and a study of a new cancer treatment were also on board as the Falcon 9 rocket lifted off from Cape Canaveral, Florida at 5:42 am (0942 GMT).

"We have ignition and liftoff! The Falcon 9 rocket powers the Dragon spacecraft toward the International Space Station," said a NASA commentator as the white rocket soared skyward under cover of darkness on the early Florida morning.

The unmanned Dragon capsule carried 5,900 pounds (2,700 kilograms) on its 15th supply mission to the orbiting lab, as part of a $1.6 billion contract with NASA.

Both the capsule and the rocket have flown before. The Dragon sent cargo to space ion 2016 and the Falcon blasted off a NASA satellite two months ago.