Just before midnight on Tuesday, the United Launch Alliance is set to launch its most powerful rocket from Cape Canaveral, Florida, lofting a classified spy satellite for the National Reconnaissance Office. The mission is finally ready to fly a full month after the rocket’s first launch attempt, which was aborted just three seconds before liftoff.
The rocket going up on ULA’s mission is the Delta IV Heavy, a giant vehicle that consists of three rocket cores strapped together to provide extra thrust. It’s one of the most powerful rockets in the world, though it falls short of the power packed into SpaceX’s Falcon Heavy. ULA doesn’t fly the Delta IV Heavy very often, as it’s an expensive vehicle to make, but the company uses the rocket for…