Ariane 5 ECA new elements

The ESC-A stage reused the reliable HM-7B rocket engine implemented on the third stage of the Ariane 4 launcher. Its mission is to provide the complementary energy necessary to reach the target orbits. The stage also provided roll control during the propulsion phase and during the separation sequences of the payloads.

The ESC-A stage was composed of:

• two cryogenic tanks (one for liquid hydrogen, the other for liquid oxygen) containing 14.7 tonnes of ergols
• the HM7B engine which operates for nearly 940 s and delivered a thrust in vacuum of 6.5 tonnes

Vehicle Equipment Bay C (VEB-C)

Modifications were also introduced on the Vehicle Equipment Bay (VEB) used for the Ariane 5 Generic version.

The new VEB was adapted to the A5 ECA configuration:

• it operated in a “cryogenic” environment
• it did not support the EPS stage in its middle volume anymore
• it no longer needed to carry the attitude control system (SCA) as that function was provided by the ESC-A stage itself
• it was made, as before, in composite material, but was smaller and lighter
• it reused the electrical equipments of the Ariane 5 Generic Plus version

A conical adaptor structure was developed and mounted on top of the VEB-C structure to provide at its upper interface the Ariane standard diameter of 2624 mm where the payload adaptor was fixed.

Changes at Europe’s Spaceport

To accommodate this larger version of the Ariane 5 several changes were made to the equipment and facilities at Europe's Spaceport. For instance, the new upper stage of the Ariane 5 ECA made the launcher taller so the roof of the Ariane 5 Final Assembly Building was raised by more than four metres.

The launch tower was also been adapted to fit the height of the new launcher and the arms that carried the propellant feed lines and electrical connections to the launcher's new upper stage.