Launched in 1960, Echo 1 was designed to explore the new field of communications via space. Its design was remarkably simple: Essentially a large balloon, measuring 30 meters (100 feet) across, the
Communications satellites
Echo
1950s echo satellite hi-res stock photography and images - Alamy
Echo 1 satellite hi-res stock photography and images - Alamy
Project Echo 1
Satellite communication - Development of satellite communication | Britannica
The Balloon Satellites of Project Echo | Amusing Planet