Ariane 5 cryogenic main stage (EPC)

The EPC was essentially composed of an aluminium tank with two compartments: one for liquid oxygen and one for liquid hydrogen. The upper compartment contained 133 tonnes of liquid oxygen and had a capacity of 120 m3, while the lower compartment contained 26 tonnes of liquid hydrogen and had a capacity of 390 m3. Both propellants were produced at plants located inside Europe’s Spaceport in French Guiana.

The tanks were only a few millimetres thick: 1.3 mm for the hydrogen and 4.7 mm for the oxygen. Given the structural characteristics of the main stage, when the tanks were empty they had to be pressurised to prevent them buckling under their own weight. Innovative technology and extremely precise welding machines were needed to produce them.

At the base of the EPC was the Vulcain engine which transmitted thrust to the launcher through the aft ‘skirt’, while at its summit was a forward ‘skirt’ linking the main stage to the launcher’s upper stage and upper part configuration. This element, called JAVE from its name in French "Jupe AVant Equipée", was a major structure of the launcher as it transmitted thrust from the two solid boosters to the launcher in order to lift the fully loaded EPC.

The Vulcain engine operated for just under 10 minutes before it shut down. At this point, at an attitude of around 145 km, the main stage separated and followed a side ballistic trajectory during which it was spun on a transversal axis before reentering the atmosphere. Most of it burned up in the atmosphere and the remaining parts fell into the Pacific Ocean, some 2000 km off the coast of South America.

Responsible contractor:EADS SPACE Transportation (France)
Cryogenic tanks: CRYOSPACE (France)
Thrust frame: Dutch Space (The Netherlands)
Forward skirt: MAN (Germany)
Vulcain engine: SNECMA MOTEURS (France)