Today in Technology History

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April 24

Many people receive television signals that are transmitted via satellites far above the Earth. Today marks the fortieth anniversary of the first time TV signals were relayed by a satellite.

The first satellite launched into orbit was, of course, the Soviet Sputnik in 1957. In April 1960, the first weather satellites were sent up. When NASA launched the Echo I satellite in August of 1960, it was the largest object yet to go to space. Like a weather balloon, it started small and then inflated to a 100-foot diameter. Echo I was made of Mylar and coated with aluminum. A newspaper account the day after its launch called Echo I "the world's largest, most visible and most vulnerable artificial satellite."

Today's communications satellites amplify the signals they receive before re-transmitting them. Not so the aptly-named Echo I which, thanks to its aluminum coating, passively reflected the signals that were aimed at it. Scientists experimented with bouncing radio and microwaves off the shiny sphere, which orbited 1,000 miles above the Earth. The satellite could even be used for two-way voice communication.

On April 24, 1962, scientists working for M.I.T. and the U.S. Air Force successfully bounced television signals off Echo I. The signal was sent from an M.I.T. lab in California; it was picked up in Massachusetts, 2,700 miles away. The TV signal simply consisted of the word "M.I.T.," written in block letters. The age of satellite television had begun.

Related link:

• Click here to read more about the Echo I satellite.

 

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