July 10, 1962: Telstar, The First Communications Satellite


July 10, 1962: Telstar, The First Communications Satellite

What now seems common, was anything but, when Telstar went into orbit. Launched by NASA aboard a Delta rocket from Cape Canaveral on July 10, 1962, Telstar 1 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, inclined at an angle of approximately 45 degrees to the equator.This is in contrast to most of today’s communications satellites, which are placed in circular geostationary orbits.

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. Ground antennas had to track the satellite with a pointing error of less than 0.06 degrees as it moved across the sky at up to 1.5 degrees per second.

Since the transmitting and receiving radio systems on board Telstar were not powerful, the ground antennas had to be huge. Bell Laboratories built the electrical portions of the system that steered the antennas. The aperture of the antennas was 3,600 square feet. The antennas were 177 feet (54 m) long and weighed 380 tons (340,000 kg). The antennas were housed in radomes the size of a 14-story office building.

The top link is to a short version video, the bottom to a very detailed longer version from the AT&T Archives. Enjoy!

http://www.youtube.com/watch?v=sRHpl2gZOo0
http://www.youtube.com/watch?v=uKH-GijnAGk

To see more from the AT&T Archives, visit http://techhchannel.att.com/archives The story of how the Bell System, in cooperation with NASA, developed the Tels…

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8 thoughts on “July 10, 1962: Telstar, The First Communications Satellite

  1. Telstar 1 was most likely “killed” by radiation injected into the lower Van Allen belt from the Starfish high altitude nuclear test. It was a 1.4 MT at 400 km and the effects extended out to 1200 km. Telstar was in a elliptical enough orbit to take it through the lower Van Allen twice per orbit.

  2. I recall, the first transmission was our National Anthem and the Stars and Stripes…someone forgot about mix-minus, as there was return audio for about 10 secs.. Corrected the audio, and use the recording at sign-off.

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