Tech UPTechnologysatellite telecommunications

satellite telecommunications

On July 10, 1962, Telstar 1 , a sphere eighty-eight centimeters in diameter and seventy-seven kilos in mass, was put into orbit, destined to connect Europe with America by telephone and television , which radically changed the world of communications. communications. Its mission was to receive the waves emitted at stations located on both continents, amplify them and transmit them on another frequency. Its orbit, an ellipse that was covered by the satellite in two hours and thirty-seven minutes, was inclined 45º with respect to the equator and was at a distance of between one thousand and six thousand kilometers from the earth’s surface. It was not a geostationary orbit, and each pass over the Atlantic saw the satellite simultaneously from both continents for only thirty minutes, so that was the maximum duration of a broadcast. The fruit of a project financed by various companies on both sides of the ocean, it had been built by a team from Bell Telephone Laboratories . The launch from Cape Canaveral, mounted on a Thor-Delta rocket, was carried out by NASA.

That achievement was something to be satisfied with: “La, la, la, hauts les cœurs, avec moi tous en chœur”, (“Up the hearts, all in chorus with me”), Yves Montand sang in a recorded performance of La chansonnette , which It was broadcast during the first test carried out from Europe to America, after an intervention by the French Minister of Communications. Shortly before midnight on July 10, American technicians had activated the satellite and for seven minutes they broadcast the first image from the United States, which was captured at the French station. The public broadcast that served to premiere “mundovisión” was on July 23 and included a live press conference by President Kennedy .

The initiative was a technological response to the bottlenecks that telephone communications suffered in the submarine cables across the Atlantic in the late 1950s, which put a brake on economic development. An attempt was made to solve the problem with the signing of a collaboration protocol between France, Great Britain and the United States to create a satellite telecommunications system. The transmission of the Telstar would not have problems of electrical supply as it carried rechargeable nickel-cadmium batteries, thanks to three thousand six hundred photoelectric cells that were powered by the Sun; its limitation was that it would only have a power of fourteen watts, so the ground antennas had to be huge.

The solution led to the construction of a station in Andover, Maine, with a 54-meter, 340-ton mobile paraboloid horn antenna protected by a polyester radome the height of a 14-foot building. floors. On the European side, it materialized in the installation of two receiving antennas, one British in Goonhilly Downs (Cornwall) and another French in Pleumeur-Bodou (Britain), which was not available until three days before the launch of Telstar. Antennas were also installed in Canada, Germany and Italy. Those devices had to locate a sphere less than a meter in diameter, moving at a speed of eight kilometers per second and more than a thousand kilometers high.

Telstar greatly improved telecommunication possibilities : since 1960 there was Echo 1, the first passive satellite, which consisted of a huge balloon, thirty meters in diameter (it could be seen with the naked eye from Earth), covered in aluminum , which acted as a mirror to return the microwaves it received to the surface. It was much more sophisticated; It contained a thousand transistors inside, was capable of amplifying the signal more than ten thousand times, transforming the frequency of the microwaves (from 6 GHz to 4 GHz) and transmitting them in all directions. It stopped working in 1963, a victim of the Cold War and its high-altitude nuclear tests, which filled the Van Allen belt with radiation and made it difficult for its transistors to work.

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