Behind the scenes with Telstar

Etiquetas

1960 | PIERCE | Satélite
Personaje: PIERCE, John Robinson.

Created by the Bell Telephone System and released in 1962, "Behind the scenes with Telstar" tells story of how the Bell System, in cooperation with NASA, developed the Telstar satellite, and participated in the launch and the subsequent successful transmission of signals to and from the earth and space.

Telstar 1 launched on top of a Thor-Delta rocket from Cape Canaveral on July 10, 1962. It successfully relayed through space the first television pictures, telephone calls, and fax images, and provided the first live transatlantic TV feed. Telstar 2 launched May 7, 1963. Telstar 1 and 2 -though no longer functional- still orbit the Earth. Belonging to AT&T, the original Telstar was part of a multi-national agreement among AT&T (USA), Bell Telephone Laboratories (USA), NASA (USA), GPO (United Kingdom) and the National PTT (France) to develop experimental satellite communications over the Atlantic Ocean. Bell Labs held a contract with NASA, paying the agency for each launch, independent of success.

The American ground station -built by Bell Labs- was Andover Earth Station, in Andover, Maine. The main British ground station was at Goonhilly Downs in southwestern England. The French ground station was at Pleumeur-Bodou (48°47'10"N 3°31'26"W) in north-western France. The satellite was built by a team at Bell Telephone Laboratories that included John Robinson Pierce, who created the project; Rudy Kompfner, who invented the traveling-wave tube transponder that the satellite used; and James M. Early, who designed its transistors and solar panels. The original Telstar had a single innovative transponder that could relay data, a single television channel, or multiplexed telephone circuits. Since the spacecraft spun, it required an array of antennas around its "equator" for uninterrupted microwave communication with Earth.

Telstar 1 was the first privately sponsored space launch. Telstar was placed in an elliptical orbit completed once every 2 hours and 37 minutes, inclined at an angle of approximately 45 degrees to the equator, with perigee about 952 kilometres (592 mi) from Earth and apogee about 5,933 kilometres (3,687 mi) from Earth. Due to its non-geosynchronous orbit, Telstar's availability for transatlantic signals was limited to the 20 minutes in each 2.5 hour orbit when the satellite passed over the Atlantic Ocean. The antennas were housed in radomes the size of a 14-story office building. Two of these antennas were used, one in Andover, Maine, and the other in France at Pleumeur-Bodou. The GPO antenna at Goonhilly Downs in Great Britain was a conventional 26-meter-diameter paraboloid.

Telstar 1 relayed its first, and non-public, television pictures -a flag outside Andover Earth Station- to Pleumeur-Bodou on July 11, 1962. Almost two weeks later, on July 23, at 3:00 p.m. EDT, it relayed the first publicly available live transatlantic television signal.The first pictures were the Statue of Liberty in New York and the Eiffel Tower in Paris. The first broadcast was to have been remarks by President John F. Kennedy, but the signal was acquired before the president was ready, so engineers filled the lead-in time with a short segment of a televised game between the Philadelphia Phillies and the Chicago Cubs at Wrigley Field. From there, the video switched first to Washington, DC; then to Cape Canaveral, Florida; to the Seattle World's Fair; then to Quebec and finally to Stratford, Ontario. The Washington segment included remarks by President Kennedy. Telstar 1, which had ushered in a new age of the commercial use of technology, became a victim of technology during the Cold War. The day before Telstar 1 launched, a U.S. high-altitude nuclear bomb (called Starfish Prime) had energized the Earth's Van Allen Belt where Telstar 1 went into orbit. This vast increase in a radiation belt, combined with subsequent high-altitude blasts, including a Soviet test in October, overwhelmed Telstar's fragile transistors. It went out of service in November 1962, after handling over 400 telephone, telegraph, facsimile and television transmissions. It was restarted by a workaround in early January 1963. The additional radiation associated with its return to full sunlight once again caused a transistor failure, this time irreparably, and Telstar 1 went out of service on February 21, 1963.
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