In-flight control and guidance power for new Ariane 5 ECA satellite launch vehicle

Citation

(2006), "In-flight control and guidance power for new Ariane 5 ECA satellite launch vehicle", Aircraft Engineering and Aerospace Technology, Vol. 78 No. 1. https://doi.org/10.1108/aeat.2006.12778aaf.009

In-flight control and guidance power for new Ariane 5 ECA satellite launch vehicle

In-flight control and guidance power for new Ariane 5 ECA satellite launch vehicle

Keywords: Spacecraft, Satellite computers

Saft, the manufacturer of high-end batteries for industrial applications, has signed a contract with EADS SPACE Transportation to provide all the in-flight battery systems for the next 30 Ariane 5 launch vehicles ordered by Arainespace to EADS Space Transportation. This order mostly consists of the new A5 ECA version. To meet the demanding requirements of the Ariane 5 contract Saft will develop and manufacture a variety of specialised spacecraft batteries incorporating both rechargeable and primary battery technologies.

The Ariane 5 ECA represents a major milestone for the European Space Agency (ESA). It has been developed to keep pace with trends in the commercial launch market, especially the need to launch larger and heavier satellites, while reducing launcher production costs. Equipped with the Vulcain 2 main engine and the new cryogenic upper stage (ESCA), it is capable of boosting payloads of up to 10tonnes into geostationary transfer orbit for a single or dual launch project (two satellites at once). In its version with the reignitable storable propellant upper stage (A5 ES version), it can also carry the ATV towards the International Space Station into low Earth orbit.

The generic version of Ariane 5 has already enjoyed 18 successful flights and one world record: the largest telecommunications satellite ever to be placed into geostationary transfer orbit, Thai¨com 4-Ipstar, launched on August 11, 2005.

For the generic Ariane 5, Saft is providing a total of 18 individual battery systems to power key elements including:

The Vehicle Equipment Bay (VEB) is often called the “brains” of a launcher. Situated on top of the main cryogenic stage its computer systems provide autonomous control for all the systems required to control a flight for its duration such as Vulcain engine ignition, and separation of the boosters and the storable propellant upper stage. Power for the inertial guidance and control systems is provided by two 60 V silver oxide-zinc (AgOZn) primary batteries, each comprising 39×14 PNS cells capable of supplying 17 A for 65 min.

Also in the VEB, four rechargeable 30 V nickel-cadmium (Ni-Cd) batteries, each comprising 25×VR1.6CE cells, power the pyrotechnic and safety systems.

The EPC is essentially made of an aluminium tank with two compartments: one for liquid oxygen and one for liquid hydrogen. At the base is the Vulcain engine which operates for approximately 10 min until the main stage separates.

Power for the EPC guidance and control systems is again provided by two 60 V AgOZn batteries, while six 30 V Ni-Cd batteries power the pyrotechnics – for stage and booster separation – and safety systems.

The Ariane 5 solid propellant boosters, attached to both sides of the main cryogenic stage, are the largest solid rocket boosters ever produced in Europe. Each contains around 238 tonnes of propellant and together they provide 630 tonnes of thrust, 92 percent of the thrust needed at lift-off.

Two 30 V Ni-Cd batteries power the EAP telemetry systems and a further two 30 V Ni-Cd batteries power the booster recovery systems that indicate their position so they can be recovered from where they fall into the Atlantic Ocean, some 450 km from the launch site in French Guiana.

As well as the more powerful Vulcain 2 main stage engine and enhanced solid boosters, the key element in the Ariane 5 ECA is a new more powerful cryogenic upper stage powered by the HM-7B engine from the Ariane 4 launcher. This requires three additional 40 V batteries to power the cryogenic pump that supplies fuel to the engine.

EADS SPACE Transportation, the single Prime Contractor for the Ariane 5 system, issued a demanding specification that called for the design, development and supply of a reliable, high performance and cost-effective battery system. Saft drew on its extensive experience from the Ariane 4 programme to deliver the optimum solution in the form of rechargeable silver oxide-zinc (AgOZn) battery systems, each comprising 27×10 LAS cells, capable of supplying 10 A for 60 min.

The Saft batteries proved their capability in the successful first qualification flight of the Ariane 5 ECA in February 2005. And the result was the confirmation of the contract to supply all the flight batteries for the Ariane 5 programme through to 2010.

The Ariane 5 batteries are being designed and manufactured at Saft plants in Poitiers and Bordeaux, France.

Details available from: Saft Specialty Battery Group. Tel: +33 1 49 93 17 14; e-mail: antoine.brenier@saftbatteries.com