SpaceX's first Falcon Heavy rocket is now vertical on launch pad 39A at NASA's Kennedy Space Center. The fully-assembled 229-foot-tall rocket will be the most powerful in the world when it blasts off.
It will have 4.7 million pounds of thrust at launch. Elon has said first Falcon Heavy's engines will only be operated at 92 percent of full power.
The Delta 4-Heavy rocket can take 63,471 pounds (28,790 kilograms) to low earth orbit.
SpaceX's Falcon Heavy will be able to take 140,660 pounds (63,800 kilograms) to low Earth orbit.