Alternate use: Coleco Telstar, Telstar Records

The original Telstar had a roughly spherical shape

Telstar was the first active communications satellite, the first satellite designed to transmit telephone and high-speed data communications, as well as the first privately owned satellite. Its name is used to this day for a number of television broadcasting satellites.

Belonging to AT&T, the original Telstar was part of a multi-national agreement between AT&T, Bell Telephone Laboratories, NASA, the British General Post Office, and the French National PTT (Post & Telecom Office) to develop satellite communication. Bell also built the Earth Station in Andover, and held a contract with NASA, reimbursing the agency 3 million dollars for each launch, independent of success.

Launched by NASA from Cape Canaveral on July 10, 1962, Telstar was the first privately sponsored space launch. A medium-altitude satellite, Telstar was placed in an elliptical orbit (completed once every 2 hours and 37 minutes), rotating at a 45 degree angle above the equator. Because of this, its transmission availability for transatlantic signals was only 20 minutes in each orbit.

Telstar relayed its first television pictures (of a flag outside its ground station in Andover, Maine) on the date of its launch. Almost two weeks later, on July 23, it relayed the first live transatlantic television signal. During that evening it also dealt with the first telephone call transmitted through space and successfully transmitted faxes, data, and both live and taped television, including the first live transmission of television across an ocean (to Pleumeur-Bodou, in France). John F. Kennedy, then President of the United States, gave a live transatlantic press conference via Telstar.

The satellite was built by a team at Bell Telephone Laboratories. It was roughly spherical, was 34.5 inches (880 mm) long, and weighed 170 lb (77 kg). Its dimensions were limited by what would fit in one of NASA's Delta rockets. The team calculated the orbital path and located the US ground station accordingly in the US State of Maine.

Telstar was equipped with a helical antenna which received microwave signals from a ground station, then amplified and rebroadcast the signal. When received back on the ground again, the signal was only a nanowatt or so in strength and a maser amplifier was therefore used to increase signal detection ability.

Telstar, which had ushered in a new age of the benevolent use of technology, actually became a victim of the beligerant uses of technology during the Cold War. The day before Telstar was launched, the United States tested a high-altitude nuclear device (called the Starfish Prime) which super-energized the Earth's Van Allen Belt where Telstar took orbit. This vast increase in radiation, combined with further increases during subsequent high-altitude blasts overwhelmed Telstar's fragile transistors, and it went out of service on February 21, 1963. Experiments continued, and by 1964, two Telstars, two Relay units (from RCA), and two Syncom units (from the Hughes Aircraft Company) had operated successfully in space. Syncom 2 was the first geosynchronous satellite and its successor, Syncom 3, broadcasted pictures from the 1964 Summer Olympics. The first commercial geosynchronous satellite was Intelsat 1 ("Early Bird") launched in 1965.

Telstars 5–7 and 10–13 are presently (2004) operated by Loral Skynet. Telstar-8 is being manufactured by Space Systems/Loral and is due to launch in 2004.

Telstar 18 was launched in June, 2004 by Sea Launch. The upper stage of the rocket underperformed, but the satellite used its significant stationkeeping fuel margin to raise the orbit, compensating this; it has enough on-board fuel remaining that will allow it to exceed its specified 13-year life.

Joe Meek composed a popular instrumental recording in 1962, named Telstar after the satellite; it was performed by The Tornados. Sound effects on the record, intended to symbolize radio signals, were produced by Meek running a pen around the rim of an ashtray, and then playing the tape of it in reverse.

In the Netherlands, a football club formed from a merger was named SC Telstar after the satellites.

In the United States the heavy metal band Helstar took their name partly from the satellite as well.