Evolution to adjust Ariane 5 to market conditions
Le Bourget, 01 June 2001
The requirements of commercial satellite operators and other space payload customers are growing steadily. Communication satellites, for example, do not only increase in efficiency but also in size and weight. However, maintaining the position as the world's leading supplier of launcher systems in the long run requires continuous evolution of the European launcher system Ariane 5. Within the Ariane 5 Plus programme, the Space Infrastructure business division of Astrium will be responsible for all development activities in connection with the Ariane 5 upper stage and is thus the sole manufacturer of upper stages for all the Ariane versions.
Even today, Ariane 5 is considered the world's most powerful launcher for the transport of payloads to low-earth and geostationary orbits. After completion of the development phase, however, it turned out that the original design specification, a maximum payload capacity of six tons for transports to geostationary transfer orbits, would be insufficient for many future applications. Evolution of the Ariane 5 aims at gradually and continually improving payload capacity and range of applications of the launcher in order to be able to offer potential customers best launch service on accommodating terms. The Ariane 5 Plus programme consists of three major steps:
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Development of a new Ariane 5 upper stage (ESC-A) using an already existing cryogenic engine from Ariane 4,
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Development of the new cryogenic upper stage engine VINCI and adaptation to the upper stage ESC-A (ESC-B),
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Modification of the current Ariane 5 upper stage including the Aestus engine to allow versatile missions profiles (EPS-Versatile),
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Development of a new control unit.
Cryogenic engine for the upper stage
Main part of the latest Ariane 5 adaptation-to-market programme (Ariane 5 Plus) is the development of the new upper stage ESC-A (Etage Supérieur Cryotechnique A). The upper stage, which works on a cryogenic basis using supercooled, high-energy propellants (liquid hydrogen/liquid oxygen), will increase payload capacity by two tons. The propulsion system of the third stage of Ariane 4 including the cryogenic HM-7 engine will be integrated into the Ariane 5 upper stage using the existing oxygen tank and thrust structure complemented by a new hydrogen tank. Propellant mass of the upper stage engine will increase from eleven tons (standard version) to 14 tons. Using tried and tested components will cut production cost distinctly and reduce development time to three years.
At the same time, thrust of the main stage engine of Ariane 5 will be improved and propellant mass of the main stage be increased from 155 to 172 within the Ariane 5 E programme. After jettisoning of the solid-propellant boosters, the Vulcain main-stage engine will be the launcher's sole propulsion for a flight phase of eight minutes. Power of the Vulcain-2 engine will increase by about 30% to 135 tons as compared with the predecessor version. This increase in power was generated by modifying thrust chamber and turbo pump. Thanks to the new Ariane 5 upper stage ESC-A and the measures to be taken to improve the thrust of boosters and main stage, payload capacity of Ariane 5 will thus increase from about six to up to ten tons. First launch of Ariane 5ECA is scheduled for the middle of 2002.
Modified Aestus engine to allow up to five re-ignitions
At the same time, power of the upper stage EPS (Etage Propergols Stockables) of the current Ariane 5 version will also be increased. Modification of the propulsion system is intended to allow five re-ignitions of the EPS during a free-flight phase of up to six hours and delivery of satellites to different orbits. Thus, Ariane 5 will be able to meet the requirements of or than 90% of all satellite operators and can be used as a versatile means for "space transport". The so-called Ariane 5 Versatile is scheduled for first launch at the end of 2002.
Intelligent control unit the "brain" of Ariane
In the Ariane 5 programme, Astrium is responsible for the so-called "Vehicle Equipment Bay" (VEB), a control unit, the onboard computers of which will electronically control engine ignition, stage separation and flight control of Ariane 5. As to the Ariane 5 Plus programme, Astrium recently started testing of the three new VEB versions in Toulouse. These versions had been adapted to the new Ariane mission profiles and can thus be used for Ariane 5 "Versatile" and the new cryogenic upper stages.
ESA decision to be expected for November 2001
Intended goal in programme evolution is the development of the upper stage ESC-B, which will be ready for operation by 2006. This upper stage comprises the completely new, re-ignitable VINCI cryogenic engine, with the help of which payload capacity will rise to 12 tons. It will thus meet all foreseeable market requirements and ensure the competitiveness of Ariane 5.
A decision on the appropriation of the funds required for ESC-B development is expected to be taken on the occasion of this year's meeting of the council of ESA ministers to be held in Edinburgh under the presidency of the German Federal Minister of Education and Research, Edelgard Bulmahn.
Astrium is a joint company of EADS European Aeronautic Defence and Space Company and BAE Systems.
Paris/Le Bourget, June 2001
Your contact: Astrium Space Infrastructure
Mrs. Kirsten Leung
Phone: tel: +49-421-539-5326
fax: +49-421-539-4534
