Telstar is such a satellite for the overseas transmission of microwaves. Like the relay towers on land, it picks up microwave signals carrying television or other types of communications, amplifies them billions of times and then transmits them to receiving stations thousands of miles distant. Telstar is a 34½ inch sphere of 15,000 parts. It weighs 170 pounds and is orbiting the earth every 158 minutes at an apogee of 3,502 miles and a perigee of 593 miles. It was designed and built by the Bell Telephone Laboratories, paid for by the American Telephone and Telegraph Company and launched into orbit from Cape Canaveral with a three-stage Thor-Delta rocket built by the Douglas Aircraft Company. The National Aeronautics and Space Administration launched the satellite, the costs being paid by A.T.&T. Another satellite, Telstar II, is being prepared by A. T. & T. for launching this year. A third, named Relay, is being built for NASA under contract by the Radio Corporation of America and will also be launched in 1962. Both the A. T. & T. and the Relay satellites, though different in design and equipment, are of the type known as the "active," or "repeater," satellite.
They receive, amplify, and re-transmit signals from earth with equipment they contain within themselves. Telstar, for example, amplifies the signal it receives ten billion times. Active satellites differ from the “passive" type, such as Echo, which do not carry amplifying and transmission equipment, but serve merely as reflectors from which signals sent to them are bounced back to earth, as in radar. Echo, an inflatable balloon launched in 1960, is still in orbit.
NYT