[10] Common Centaur is built around stainless steel pressure stabilized balloon propellant tanks[11] with 0.51 mm (0.020 in) thick walls.

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.

For propellant, 150 kg (340 lb) of Hydrazine is stored in a pair of bladder tanks and fed to the RCS thrusters with pressurized helium gas, which is also used to accomplish some main engine functions.

Since 2014, Common Centaur has flown with the RL10-C-1 engine, which is shared with the Delta Cryogenic Second Stage, to reduce costs.

[30] The latest Common Centaurs can accommodate secondary payloads using an Aft Bulkhead Carrier attached to the engine end of the stage.

[20][35] In late 2017, ULA decided to bring elements of the ACES upper stage forward and begin work on Centaur V. Centaur V will have ACES' 5.4 m (18 ft) diameter and advanced insulation, but does not include the Integrated Vehicle Fluids (IVF) feature expected to allow the extension of upper stage on-orbit life from hours to weeks.

[36] This increased capability over Common Centaur was intended to permit ULA to meet NSSL requirements and retire both the Atlas V and Delta IV Heavy rocket families earlier than initially planned.

That will enable a whole new set of missions that you cannot even imagine doing today.”[41] Vulcan finally launched on 8 January 2024 and the stage performed flawlessly on its maiden flight.

[43] The Centaur concept originated in 1956 when the Convair division of General Dynamics began studying a liquid hydrogen fueled upper stage.

Centaur initially flew as the upper stage of the Atlas-Centaur launch vehicle, encountering a number of early developmental issues due to the pioneering nature of the effort and the use of liquid hydrogen.

[14]: 96 By the 1970s, Centaur was fully mature and had become the standard rocket stage for launching larger civilian payloads into high Earth orbit, also replacing the Atlas-Agena vehicle for NASA planetary probes.

[1] The Saturn I was designed to fly with a S-V third stage to enable payloads to go beyond low Earth orbit (LEO).

[14]: 143 The first launch of Titan IIIE in February 1974 was unsuccessful, with the loss of the Space Plasma High Voltage Experiment (SPHINX) and a mockup of the Viking probe.

It was eventually determined that Centaur's engines had ingested an incorrectly installed clip from the oxygen tank.

The Titan booster used to launch Voyager 1 had a hardware problem that caused a premature shutdown, which the Centaur stage detected and successfully compensated for.

[57] The probes were launched with the much less powerful solid-fueled IUS, with Galileo needing multiple gravitational assists from Venus and Earth to reach Jupiter.

The capability gap left by the termination of the Shuttle-Centaur program was filled by a new launch vehicle, the Titan IV.

The 1997 Cassini-Huygens Saturn probe was the first flight of the Titan 401B, with an additional six launches wrapping up in 2003 including one SRB failure.

[60] Most Common Centaurs launched on Atlas V have hundreds to thousands of kilograms of propellants remaining on payload separation.

[61] In October 2009, the Air Force and United Launch Alliance (ULA) performed an experimental demonstration on the modified Centaur upper stage of DMSP-18 launch to improve "understanding of propellant settling and slosh, pressure control, RL10 chilldown and RL10 two-phase shutdown operations.