The rocket uses a half-million gallons of fuel and has three side-by-side booster cores, each with Aerojet Rocketdyne RS-68A engines that provide a combined 2.1 million pounds of thrust at liftoff.

Firing up its three core boosters and RS-68A engines, the last 235-foot tall Delta IV Heavy rumbled into the record books Tuesday afternoon on a historic farewell flight from Cape Canaveral Space ...