Atlas V 401

The Atlas V first stage, the Common Core Booster (CCB), is 3.8 m (12 ft) in diameter and 32.5 m (107 ft) in length. It is powered by one Energomash RD-180 main engine burning 284,450 kg (627,100 lb) of liquid oxygen and RP-1. The booster operates for about four minutes, providing about 4 MN (900,000 lbf) of thrust. Thrust can be augmented with up to five Aerojet AJ-60A or Northrop Grumman GEM 63 strap-on solid rocket boosters, each providing an additional 1.27 MN (290,000 lbf) of thrust.
Centaur upper stage
The Centaur is a family of rocket propelled upper stages produced by U.S. launch service provider United Launch Alliance, with one main active version and one version under development. The 3.05 m (10.0 ft) diameter Common Centaur/Centaur III flies as the upper stage of the Atlas V launch vehicle.

The main propulsion system consists of one or two Aerojet Rocketdyne RL10 engines. The stage is capable of up to twelve restarts, limited by propellant, orbital lifetime, and mission requirements. Combined with the insulation of the propellant tanks, this allows Centaur to perform the multi-hour coasts and multiple engine burns required on complex orbital insertions.