The Balloon Satellites of Project Echo

The world’s first communication satellite was remarkably unsophisticated—a big silvery plastic balloon coated with aluminum, soaring roughly 1,000 miles above the earth. It carried no active communication components, no relays. Just two FM transmitters for telemetry purposes, powered by nickel-cadmium batteries charged by solar cells. The satellite achieved its purpose by passively reflecting any radio signal directed towards its large shiny surface. For eight years it relayed radio and television signals, and made intercontinental telephone calls possible. The best part was—any individual with the right equipment could use the satellite at no cost.

Project Echo