Today, communication satellites are an important instrument for fast, global data transfer and information exchange. Knowledge transfer, telephone links, radio and television transmissions via satellite are part of everyday life. Any point on the earth’s surface can now be reached using communi-cation satellites.
The first communication satellites operated passively, i.e. large metallized balloons reflected radio relay waves and reached the receiver in this way. Today, all communication satellites operate actively. The satellite receives the signals and returns these via directional antennas to the satellite’s “footprint”. Advanced communication satellites have powerful transmitters on board which permit direct reception.
The satellites are either positioned in geostationary orbit or in strongly elliptical orbits. This means that it is possible to reach any place on earth, apart from the poles, with three geostationary satellites that are each positioned at 120 degrees on the synchronous orbit.
The first communication satellite was the passive Echo 1 launched in the USA in 1960. The first European communication satellites were Symphonie 1 and 2, which were created in partnership between Germany and France in 1974 and 1975.
EADS and its predecessor companies have played major roles in the construction of national and international communication satellites and systems. The American Intelsat satellites have consistently used EADS as a partner for equipping these “relay stations” in orbit since 1969. EADS is now equipping the sixth generation of this satellite fleet.
The “progenitor” of European communication satellites came into the world in 1977: OTS – Orbital Test Satellite. This formed the foundation stone for the ECS satellites (European Communications Satellite). Today, these satellites are called Eutelsat. Astrium built subsystems for the platform. Astrium was also responsible for deploying the fully operational satellites Nahuel, GE-5 and Sinosat in space.
The Franco-German satellite project TV-Sat/TDF1 represented a quantum leap in quality. The satellites were equipped with a travelling wave tube (TWT). This has increased the radiated transmission output by tenfold compared with previous communication satellites. It was therefore possible to provide each household with a small parabolic antenna to receive signals directly from the satellite. The new frequency ranges offered by the Copernicus satellites allowed digital telecommunication services to achieve transmission speeds that the terrestrial networks were unable to supply. This also enabled TV programmes to be delivered to the local cable networks with nationwide coverage.
EADS is now a major player in equipping communication satellites through its Astrium space division. These satellites include the Intelsat series, satellites in the Astra series and the Eutelsat communication satellites.
