Prior to 1956 it was not possible for people to speak to each other across the Atlantic Ocean except by radiotelephone. If atmospheric conditions were poor, the connection was often interrupted. In 1956 the first trans-Atlantic telephone cable went into operation, providing 36 static-free telephone circuits. By the early 1960s, there were still only about forty channels of trans-Atlantic communication, with little promise that the ocean-bottom cables could handle future demand.

As early as 1945, however, Arthur C. Clarke, a British science fiction writer, had described the possibility of establishing a communications network covering the entire globe with three strategically orbiting satellites. Obstacles encountered in realizing these ideas immediately were many and various, however. A satellite would be exposed to extreme conditions of heat and cold. It needs an independent power supply to last for months or years. Once in orbit, it can only be reached by radio signal, so...