US entrepreneur Elon Musk has launched his new rocket, the Falcon Heavy, from the Kennedy Space Center in Florida.
The mammoth vehicle - the most powerful since the shuttle system - lifted clear of its pad without incident to soar high over the Atlantic Ocean.
It was billed as a risky test flight in advance of the lift-off.
The SpaceX CEO said the challenges of developing the new rocket meant the chances of a successful first outing might be only 50-50.
"I had this image of just a giant explosion on the pad, a wheel bouncing down the road. But fortunately that's not what happened," he told reporters after the event.
With this debut, the Falcon Heavy aims to become the most capable launch vehicle available.