The liquefied natural gas (LNG) / methane fueled booster will be powered by a pair of BE-4 engines, each producing 550,000 pounds (2,400 kN) of sea level thrust. Two graphite epoxy motor (GEM) 63XL solid rocket boosters (SRBs) generate the additional power required at liftoff, with each providing 459,600 lbs (2,044 kN) of thrust. The Centaur avionics system, provides guidance, flight control and vehicle sequencing functions during the booster and Centaur phases of flight.

IMAGE CREDITS: UNITED LAUNCH ALLIANCE