Launch table
The Delta 4 sits atop a massive launch table. The engine exhaust at liftoff will be directed into the flame trench and out a duct to the south. The six box-like structures on the table are the tail service masts that will feed the liquid hydrogen and liquid oxygen to the rocket's Common Booster Core first stage. The two center masts are used for the Delta 4 configurations that use just one core, which you see here. For Delta 4 Heavy missions that have three core boosters strapped together, the outer sets of masts will be used.
Photo: Justin Ray