Telstar was the first active communications satellite (launched in 1962), and the first satellite designed to transmit telephone and high-speed data communications. Its name is used to this day for a number of television broadcasting satellites.

Description

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, Telegraph & Telecom Office) to develop satellite communication. Bell also built the Andover Earth Station in Andover, Maine, and held a contract with NASA, reimbursing the agency three million dollars for each launch, independent of success.

The satellite was built by a team at Bell Telephone Laboratories, including John Robinson Pierce who created the project, Rudy Kompfner who invented the traveling wave tube transponder used in the satellite, and James M. Early who designed the transistors and solar panels for it. It was roughly spherical, was 34.5 inches (880 mm) long, and weighed 170 pounds (77 kg). Its dimensions were limited by what would fit in one of NASA's Delta rockets. Telstar was spin-stabilized, so its outer surface was covered by solar cells in order to always receive some power. The power produced was a relatively tiny 14W.

Telstar was equipped with a helical antenna which received microwave signals from a ground station, then amplified and rebroadcast the signal. The broadcasts were made from a series of somewhat directional feed horns distributed around the satellite's "equator". The electronics switched which antenna was active as the satellite rotated.

The main earth receiving station was Goonhilly Down in the south of England and was used by the BBC. It was the international coordinator and the standards 525/405 conversion equipment (filling a very large room at that time) was researched and developed by the BBC and located in the BBC Television Centre London. Also with Early Bird in 1964 as well as the Summer Olympics mostly coming into Europe via the BBC, the main US networks, NBC, CBS and ABC all made their contributions from Europe mainly through the BBC. (N.Smyth-Irish)

Launched by NASA aboard a Delta rocket 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), revolving at a 45 degree angle above the equator. Because of this, its transmission availability for transatlantic signals was only 20 minutes in each orbit.

In service

Telstar relayed its first television pictures (of a flag outside its ground station in Andover) on the date of its launch. Almost two weeks later, on July 23, it relayed the first live transatlantic television signal. The first broadcast was to have been remarks by President John F. Kennedy, but the signal was acquired before the President was ready, so the lead-in time was filled with a short segment of a televised major league baseball game between the Philadelphia Phillies and the Chicago Cubs at Wrigley Field Box Score (Tony Taylor was seen flying out to rightfielder George Altman). 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; 48°47′10″N, 3°31′26″W). US president Kennedy gave a live transatlantic press conference via Telstar.

Telstar, which had ushered in a new age of the benevolent use of technology, actually became a victim of technology during the Cold War. The day before Telstar was launched, the United States tested a high-altitude nuclear device (called 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, including a Soviet test in October, overwhelmed Telstar's fragile transistors; it went out of service in early December, but was restarted by a workaround in early January of 1963. The additional radiation associated with its return to full sunlight once again caused transistor failure, this time irreparably, and it went out of service on February 21, 1963.

According to the US Space Objects Registry, Telstar 1 was still in orbit as of October 2007.

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, broadcast pictures from the 1964 Summer Olympics. The first commercial geosynchronous satellite was Intelsat I ("Early Bird") launched in 1965.