Atlas-Centaur

The Atlas-Centaur was a space launch vehicle operated by the US Space Force from 1962-1989. It was derived from the SM-65 Atlas ICBM. The Atlas booster used two Rocketdyne XLR-89 engines as booster engines, and one Rocketdyne XLR-105 engine as the sustainer engine. The Centaur upper stage was attached to the top of the Atlas booster. The Centaur upper stage used two RL-10 engines. The Atlas booster used a stage-and-a-half staging method where the two booster engines would share the same fuel tanks as the sustainer engine, but would then shut down and separate from the vehicle mid-flight.

Note: The booster engines will automaticly shut down and separate from the vehicle at 20,000m.