 specification includes transmitter could improve several decibels. This page intentionally left blank Communication satellites and systems S C Pascall BSc PhD CEng MIEE Commission of the European Communities Contents 51.1 Background 51/3 International regulations 51/3 Spacecraft technology 51/5 51.4 The communication chain 51/10 Applications 51/15 51.6 Satellite systems 51/15 51.7 Future developments 51/18 Acknowledgements 51/19 References 51/19 51.10 Bibliography 51/20 This page intentionally left blank Background 51/3 51.1 Background Table 51.1 Frequency allocations for the fixed satellite service In 1883, Konstantin E Tsiolkovsky, a Russian schoolmaster ex- plained the principles of rocket flight in space. Twelve years later, he mentioned the possibilities of artificial satellites circling the Up-links (GHz) Down-links (GHz) earth outside its atmosphere. Half a century later, Arthur C Clarke 5.85 6.425 3.625 - 4.2 wrote of orbiting radio relay stations (Clarke, 1945) and identified 6.725 - 7.025 4.5 4.8 many of the advantages which satellite communication would have over terrestrial systems for long distance communication and broad- 12.75 - 13.25 10.7 - 10.95 and 11.2-11.45 casting. Above all he pointed to the unique value of geostationary 14.0 - 14.5 10.95 - 11.2 and 11.45 11.7 satellites. 11.7 - 12.2b Sputnik 1, the first man-made satellite, was put into low orbit 12.5 - 12.75c (227km X 941km X 65.1°) in October 1957 and stimulated many other tests and demonstrations of practical applications for artificial 27.5 - 29.5 17.7 - 19.7 satellites in the following years, above all for telecommunications 29.5 - 30.0d 19.7 - 20.2d By 1962 the Telstar 1 (Dickieson, 1963) and Relay 1 (NASA, 1968) satellites had demonstrated long distance telephone links between fixed earth stations. By 1964 an experimental satellite, Syncom III, for commercial systems on a substantial scale. The following notes had been placed in an accurate geostationary orbit. In the same year apply to this table: INTELSAT, an international consort