Overview

Satellite communications ^[1], no longer a marvel of human space activity, have evolved into an everyday, commonplace thing. By 2010, satellite systems will represent well over $100 billion of investment and provide an essential ingredient to many businesses and governments worldwide. Nearly all television coverage travels by satellite, today reaching directly to the home from space. Even in the age of wideband fiber optic cables and the Internet, satellites still serve the basic telecommunication needs of a majority of countries around the world. For example, domestic satellites have greatly improved the quality of service of the public telephone system and brought nations more tightly together. Satellites are adapting to developments in multimedia information and personal communication, with the cost of one-way and two-way Earth stations now within the reach of many potential users. A unique benefit has developed in the area of emergency preparedness and response. When a devastating earthquake hit Mexico City in September 1985, the newly launched Morelos 1 satellite maintained reliable television transmission around the nation even though all terrestrial long-distance lines out of the city fell silent. Similarly, communications were restored to facilitate disaster relief on the island of Sumatra after the December 2004 earthquake and subsequent tsunami.

To provide an overview of the field, the remainder of this chapter describes the features of satellite communication networks as well as the principal elements of an overall system. The brief history in Chapter 2 is intended to explain how the satellite industry developed and why...