Symphonie

Symphony was the name of a German - French communications satellite project. The name can be translated as harmony and should express the absolutely equal cooperation between the former West Germany and France.

Two satellites were built with that name. The satellites were stabilized with a spin wheel and thrusters. Its main body has the shape of a hexagonal prism, and its three fold boom cells are respectively offset by 120 ° to each other. The solar boom were rigidly attached to the spacecraft and were therefore successively illuminated during a Erdumlaufes from both sides. They wore therefore on both sides of solar cells.

Each satellite has two parabolic antennas for data transmission in a western and / or eastern footprint and a smaller horn antenna for the reception of data from the visible third of the earth. Each satellite had two transponders with 90 MHz bandwidth on board. The ground station could choose on which of the two satellite dishes should send a transponder ( the transponder selection of both a transmitting antenna was possible) by radio command. You could transfer a TV program and 132 voice channels, respectively. The symphony satellites were the most technically advanced communications satellites of its time.

The launch was originally scheduled with the failed European launch vehicle. Finally, they were started with two Delta 2914 rocket from Cape Canaveral. However, the U.S. government made ​​this a requirement that the satellites would not be used for testing purposes only and operationally because they wanted to protect their own monopoly on communications satellites. This unacceptable for future satellite conditions led to the development of the Ariane 1

Because of the restrictions imposed by the U.S. about commercial use satellites for education and humanitarian communication were used. These included in particular educational television in India and Africa, transfers for the German wave, the Red Cross and peacekeeping missions of the United Nations disaster relief.

The network of ground stations reached the figure of over 50 stations worldwide in approximately 40 countries, from Argentina to Africa, the Middle East and India to China.

• Symphony 1 weighed 230 kg and was launched on 19 December 1974 at 2:39 UTC clock was the first Western European communications satellite from a Delta 2914 launch vehicle into a geosynchronous orbit and positioned at 11.5 ° West. 1977 Symphony 1 was shifted to 49 ° East, where he remained for two years before he returned to his old position.

• Symphony 2 followed on August 27, 1975 at 1:42 UTC clock and was also stationed at the position 11.5 ° West, where he remained until his decommissioning.

The lifetime of the satellite was designed for 5 years; actual achieved mission duration was exactly 10 years. Symphony 2 was on 19 December 1984 ( GSOC in Oberpfaffenhofen ) shut down by the DLR Space Operations, after he had been associated with a de - orbiting maneuvers from the geostationary orbit.