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Propelled into space - Astrium presents propulsion systems of the future

Berlin/Bremen, le 01 mai 2002

They propel communications satellites, research probes and the European launch system Ariane 5: propulsion products from Astrium. During the International Aerospace Exhibition ILA in Berlin-Brandenburg (6 to 12 May 2002) the Propulsion Systems business unit of Astrium will present a vast range of products for all space applications. The satellite propulsion systems sector will focus on the ion thruster RITA (Radiofrequency Ion Thruster Assembly). An extremely high efficiency makes this environmental-friendly propulsion system an interesting solution for satellite customers from all over the world. The launch systems sector will display a flying model of the Vulcain 2 thrust chamber for the first time. Vulcain 2 will be used on the main stage of Ariane 5 from 2003. Vinci, the first European re-ignitable cryogenic upper stage engine of Ariane 5, will perform its maiden flight in 2006. A full-scale mock-up of the thrust chamber will be on display at ILA.

Successful by tradition - propulsion systems for Ariane

Astrium has been an important partner in the European launch vehicle programme Ariane since the beginning of the 1960s. As the leading thrust chamber manufacturer in Europe, the business unit has essentially contributed to the success of Ariane, the most successful commercial satellite launcher worldwide with a market share of 60 percent. The Propulsion Systems business unit of Astrium is responsible for the HM-7 engine of the Ariane 4 upper stage as well as for the thrust chamber system of the Vulcain main stage engine and the complete upper stage engine Aestus of Ariane 5. The thrust chamber is the "heart" of each propulsion system. Vulcain 2 is the most powerful Astrium engine. A thrust of 135 tons (1,350 kN), which corresponds to a power of more than 4,000,000 hp, is produced at combustion temperatures of up to 3,0000C. Thus, one single Vulcain 2 engine is providing more thrust than the four engines of a long-range airliner together.

A technological marvel - cryogenic valves

Within the Ariane programme, Astrium is also responsible for the development and production of the cryogenic valve systems of the HM-7 and Vulcain engines. These valves are designed to control pressure in the propellant tanks as well as supply of the cryogenic propellants liquid oxygen and liquid hydrogen to the Vulcain engine and allow precise control of the highly energetic propellant components. Only 30 Watt of electrical power are available to operate the valves. Tank pressure, however, is 150 bar (ambient air pressure is one bar). Metaphorically speaking this means that the cryogenic valves are capable of withdrawing the plug of a completely filled bath tub by means of a thin sewing thread - indeed, a technological marvel.

More thrust for more payload

With a market share of 60 percent in the commercial satellite launch segment, Ariane is the most successful launch system worldwide. In order to be able to maintain this position despite increasingly competitive trading conditions in the commercial satellite transport market, Ariane 5 will be gradually and continually developed further. The "Ariane 5 Plus" programme particularly focuses on increasing the payload capacity of the launch vehicle from currently six tons to up to twelve tons until 2006. Improving the power of the propulsion systems plays a decisive role in this context. In a first step, power of the main stage Vulcain engine has been increased by more than 30 percent to 135 tons as compared with the predecessor version. First launch of Vulcain 2 on an Ariane 5 is scheduled for 2002.

Cryogenic engine for the upper stage

Main part of the Ariane 5 Plus programme is the development of a cryogenic Ariane 5 upper stage. Cryogenic propellants produce a higher thrust than conventional storable propellants as used with the present upper stage engine Aestus. In a first step, the tried and tested cryogenic HM7 engine of the third stage of Ariane 4 will be integrated into the newly developed Ariane 5 upper stage and complemented by a new hydrogen tank. The ESC-A (Etage Supérieur Cryotechnique A) will have a payload capacity of up to eight tons.

Astrium is also responsible for the thrust chamber system of the first European re-ignitable, cryogenic upper stage engine, Vinci. Vinci is a completely new development and will become a central part of the ESC-B (Etage Supérieur Cryotechnique B). The engine shall be ready for use in 2006. Vinci will help to increase payload capacity of Ariane 5 to twelve tons. The engine will allow five re-ignitions and will thus meet all market requirements from today's point of view.

Propulsion solutions for new markets

Together with partners from all over the world, the Astrium Propulsion Systems business unit develops new concepts for opening up new markets. The Astrium engine Aestus of the upper stage of Ariane 5, for example, formed the basis for the development of a turbopump engine, which was jointly tested by Astrium and Boeing-Rocketdyne. Although tailored to the specific needs of the US market, the engine could be used on European launch vehicles as well. With a thrust of more than five tons, RS-72 is a powerful upper stage engine, which, for example, could also be used on the US launchers Delta II and Delta IV.

Reusable propulsion systems ensure access to space

Cost pressure on launch services is growing steadily. That is why Astrium is working on new low-cost propulsion system concepts not only for conventional but also for future reusable launch vehicles (RLV). Within the framework of the national research programme ASTRA (Advanced Systems and Technologies for RLV Application) Astrium, in co-operation with Deutsches Zentrum für Luft- und Raumfahrt (DLR) and several universities, is developing new production technologies and construction methods for thrust chambers with particular focus on repeated use of such components. Development comprises, among others, the testing of new materials such as fibre-reinforced ceramics, which due to their high temperature resistance could contribute to a significant increase in service life. The new propulsion technology shall be available to an RLV development in the year 2007. Astrium starts from the assumption that current launch costs of USD 15,000 to 20,000 per kilogram of payload into geostationary transfer orbit (GTO/36,000 kilometres) could be reduced by at least 50 percent through the use of reusable launch systems. ASTRA has a volume of 5.8 million euro in the propulsion systems sector.

New propellants - environmentally compatible and efficient

In addition to new propulsion systems, the Propulsion Systems business unit is also working on alternative propellants. The socalled "green propellants" are characterised by high environmental compatibility and uniform combustion behaviour.

Propellant combinations of liquid hydrogen and various hydrocarbides are currently being tested at Astrium.

Good things come in small packages - small-type engines for orbital and attitude control

Small-type engines manoeuvre satellites and probes into their final orbit. Fine adjustment is carried out by miniature engines to precisely keep track and attitude. We do not talk about the enormous energies and forces developed in the thrust chamber systems of launch vehicles but about very small pulses. Astrium is the most important manufacturer of small-type engines and complete satellite propulsion systems in Europe. Small-type engines are developed, built and tested in the business unit's facilities in Lampoldshausen, Germany. With about 400 units a year, Astrium has started quasi-serial production in some of its product segments.

Conventional satellite engines are driven by chemical propellants. Astrium offers a wide range of products for many applications. The smallest engine with a thrust of 0.02 N generates a power of 0.6 hp - just a little hiss in space but sufficient enough for the track corrections required. A 5-cm large 10-N engine has a power of 20 hp and a 400-N apogee thruster generating a power of 850 hp puts any car engine in the shade. Chemical satellite engines are particularly suitable for orbital and attitude control of satellites in low-Earth or geostationary orbits. Astrium's engine know-how is also used for attitude control of the unmanned automated transfer vehicle ATV, the supply vehicle of the International Space Station.

Ion thrusters for deep space missions

Ion thrusters are the propulsion systems of the future. The Astrium-developed ion thruster RITA (Radiofrequency Ion Thruster Assembly) is characterised by extremely low propellant consumption and high efficiency. Thus, the economical ion thruster will be particularly suitable for extended missions to planets such as Mars, Mercury or Saturn. These so-called deep space missions require propulsion systems with a long service life, as service life of a satellite is primarily restricted by the propellant quantity available. RITA is also suitable for orbital and attitude control of satellites in low-Earth and geostationary orbits. At present, RITA is used on the ESA' Artemis telecommunications satellite. The successor model RITA-150 shall be ready for service by 2003.

Roll control engines for the Ariane launch vehicle

Small-type engines from Lampoldshausen are not only used for orbital and attitude control of satellites alone. With its six small 400-N engines, the attitude control system SCA (Système Contrôle d'Attitude) of Ariane 5 monitors and controls roll attitude during the thrust phase after separation of the solid-propellant boosters to thus ensure correct ascent of the launcher. The SCA is also used for precise positioning and alignment of the Ariane upper stage during flight.

Tank systems for microgravity conditions

Many things that are easy on Earth turn out to be a problem in space - fuelling, for instance. Whereas the propellant always stays at the lowest point of the tank under gravity conditions, it spreads out more or less arbitrarily in space. Complex technology is required to ensure that the engine of a space vehicle is supplied with the right quantity of bubble-free propellant at any time without starting spluttering. The Propulsion Systems business unit has developed propellant tanks for different space applications for more than 20 years. Activities focus on satellite tanks for large GTO satellites and small satellites in low-Earth orbit (LEO) as well as on propellant supply to the attitude control system of Ariane 5 and the development of tank systems for the ATV. More than 260 tanks of different makes have been delivered to customers all over the world.

Within the Space Infrastructure business division, the business unit Propulsion Systems consolidates all propulsion systems activities of Astrium, Europe's largest aerospace company. Located in Bremen, Ottobrunn near Munich and Lampoldshausen, the unit develops and produces complex propulsion systems and components for thrust and attitude control systems of launchers, satellites and platforms. The Propulsion Systems business unit is managed by Dr. Axel Deich and has a labour force of 600. Turnover is about EUR 120 million.

Berlin, May 2002

Your contact:

Kirsten Leung
Astrium Space Infrastructure
Phone: +49-421-539-5326 / Fax: +49-421-539-4534
e-mail: presse-si@astrium-space.com

Bianca Zotz
Astrium Space Infrastructure
Phone: +49-89-607-27244 / Fax: +49-89-607-29765
e-mail: bianca.zotz@astrium-space.com