/sci/ - Science & Math

>For Vulcan, the upper stage will be an upgraded version named Centaur V. The upper stage will be the same diameter as the Vulcan first stage, 5.4 meters, compared to Centaur III’s 3.05-meter diameter. Centaur V will always be powered by two RL-10 engines.

>Currently, Centaur III uses hydrazine to power its attitude control thrusters, which requires a separate propulsion system from the liquid hydrogen and liquid oxygen system for the RL-10 engine. However, Bruno says the ULA is studying the opportunity to use thrusters powered by hydrogen and oxygen in order to eliminate the second propulsion system. This would also allow a more complete and efficient use of the stage’s energy, leaving less unused residual propellant on board. According to Bruno, Centaur V is currently planned to include this new thruster system in its baseline configuration.