CAPE CANAVERAL, Fla. -- The most powerful version of Boeing's Delta 4 rocket, known as the Delta 4 Heavy, was rolled out to its launch pad last week for tests at complex 37.

The vehicle features three of the common booster core rockets strapped together, seen here. At launch the rocket also will include an upper stage and a nose cone.

For the first launch next summer the rocket will fly a demonstration mission with an instrumented payload -- officials don't want to call it a dummy satellite -- to prove the new configuration will work.

The rocket now at pad 37 will remain there until launch. It will be put through simulated countdowns and eventually have its upper stage and payload installed, topping the vehicle off at 235 feet.

Credit: Boeing