To streamline the assembly process, Ariane 5’s vehicle equipment bay and ESC-A cryogenic upper stage are installed as a single unit atop its cryogenic core stage.The Ariane 5 ECA launcher version utilizes the ESC-A cryogenic upper stage, which is powered by an HM7B engine.They deliver more than 90 percent of the launcher’s total thrust at the start of flight and burn for 130 sec.before they are separated over a designated zone of the Atlantic Ocean.Ariane 5 utilizes two solid boosters, each standing more than 30 meters tall with 237.8 metric tons of propellant.The boosters are ignited on the launch pad once the main cryogenic stage’s Vulcain engine has stabilized its thrust output.The combustion process is initiated by a pyrotechnic device, and the solid propellant burns at a radial velocity (from the center outward) of approximately 7.4 mm/sec.Flight control is provided by the boosters’ movable nozzle, which is driven by hydraulically-controlled servoactuators.
A propellant mix of 68 percent ammonium perchlorate (oxidizer), 18 percent aluminum (fuel), and 14 percent polybutadiene (binder) is used in the solid rocket motors.
As the central element of Ariane 5, the core cryogenic stage serves as one of the launcher’s key propulsion systems.
It carries a propellant load of 132.27 metric tons of liquid oxygen and 25.84 metric tons of liquid hydrogen to feed the stage’s Vulcain main engine.
The Vulcain burns for just under 600 seconds, providing up to 116 metric tons of thrust in vacuum.
The stage has an overall length of 30.5 meters from the Vulcain main engine’s nozzle to the forward (upper) skirt.