Ariane 5 ECA - New elements
Ariane 5 ECA is a higher capacity Ariane 5 Generic launcher. Although it has the same general architecture, a number of changes have been made to the basic structure of the Ariane 5 Generic version to increase thrust and enable it to carry heavier payloads into orbit.
Solid boosters
The upper segment of the Ariane-5 ECA boosters can carry 10% - approximately 2.5 tonnes - more propellant. This extra propellant gives the Ariane 5 ECA an additional 50 tonnes of thrust in the first 20 seconds following liftoff. This means that together the twin boosters deliver a thrust of 1400 tonnes at liftoff, nearly 10 times the level delivered by the engine of the central stage.
The boosters are also equipped with a new nozzle that has fewer parts and is easier and cheaper to produce.
Main stage
The Ariane-5 Vulcain cryogenic main-stage engine has been modified to increase its thrust by 20% to 137 tonnes. This new version, called Vulcain 2, operates under slightly higher pressure with a mixture ratio that has 20% more liquid oxygen than the Vulcain 1. Because of this change in the mixture ratio, a new oxygen turbopump has been developed capable of operating at 13 000 rpm to deliver a pressure of 161 bar. To hold the extra liquid oxygen needed for the central core stage operation, the capacity of the liquid oxygen tank has been increased by 16 tonnes.
This has been acheved by relocating the common tank bulkhead between the liquid oxygen tank and the liquid hydrogen tank of the ?? generic EPC stage. The new fuel load capacity of the booster is ??
In addition, the Vulcain 2 engine has a new nozzle to allow exhaust from the turbopumps to be reinjected into the main system, thus improving the engine performance at high altitude.
Thanks to these modifications the Vulcain 2 engine is able to provide an additional lift capability of 1.3 tonnes into geostationary transfer orbit.
Cryogenic upper stage
Ariane 5 ECA has a new more powerful cryogenic upper stage able to contain 14 tonnes of propellant. The cryogenic upper stage is powered by the HM-7B engine used by the extremely reliable Ariane-4 launcher.