The idea behind a communications satellite is simple: send a signal into space, and send it back down to another spot on the globe. In NASA's early days, engineers discovered the easiest way to accomplish this: bounce signals off a giant metal balloon floating in orbit. The concept was developed into the aptly-named Echo program, and Echo 1A became the first successful launch of the project on
Aug. 12, 1960.
Echo 1A, now commonly known as just Echo I, was a 100 foot diameter balloon made of mylar polyester. The spacecraft was designed as a passive communications reflector for transcontinental and intercontinental telephone, radio, and television signals.
