Balloons 41 meters in diameter and covered in aluminum

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Google’s Loon balloons or SpaceX’s Starlink satellites to offer the internet to everyone is fine. But what about gigantic globes as a mirror to reflect communications from one point of the earth to another? NASA already experimented with it in 1960, the first “passive satellites” in history. And it worked.

Currently we do not conceive a world without satellites, they allow us to communicate remotely and also serve to position all kinds of devices thanks to GPS or other similar systems. Sixty years ago things were very different and when NASA created its first satellite it was also very different from what we have today.

Project Echo: creating the simplest satellite of all

In general terms, the function of a satellite is to receive a signal from one point on earth and transmit it to a different one. To achieve this you really don’t have to break your head very much, just a mirror is enough. It is what was essentially NASA’s first satellite: a gigantic globe-shaped mirror that reflected any signal sent to it

Project Echo was developed in the 60s of the last century from a previous idea of ​​using balloons to study the atmosphere. American engineers saw an interesting opportunity in these balloons: if they were large enough, reflective enough, and high enough … they could transmit messages. From there they got down to work and the Project Echo began.

The globe was made of plastic with an aluminum coating that allowed it to reflect light. During the tests they experimented with different sizes, although in the end the first balloon that worked successfully was about 30 meters in diameter. Such a balloon the first thing one thinks of is the amount of gas needed to inflate it. Yes, it is true, an immense amount is required to inflate it, specifically 18,000 kilograms of air. But of course, once at the limits of the atmosphere due to pressure this amount drops dramatically to just a few kilograms.

The problem for NASA was not so much inflating it as being able to fold it. To get it up into the atmosphere you had to put it in a capsule and load it on a rocket. These sphere-shaped capsules were barely a meter in diameter, putting a 30-meter diameter balloon in there was the real challenge. After practice and practice, they managed to find the correct fold that would allow the capsule to open in the atmosphere, inflate the balloon and not suddenly explode. With the occasional failed attempt in between.

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Finally, on August 12, 1960, NASA’s first passive satellite successfully deployed into the atmosphere. Echo 1 transmitted as a first message a few words from the American president of the time, Dwight D. Eisenhower. “The satellite balloon, which has reflected these words, can be freely used by any nation for similar experiments in its own interest,” said the US president.

The curious thing about this satellite is just what was indicated in the message, which could be used by anyone and directly and free of charge. It was simply a mirror, so anyone with the right tools on the ground could send or receive messages.

Years later NASA sent another balloon into the atmosphere called Echo 2. This time it was somewhat larger (41.1 meters in diameter) and its somewhat more rigid structure allowed it to stay inflated without the need for a constant impulse of gas in its inside. This being somewhat larger and in a closer position, came to be seen thanks to its reflection with the naked eye (it is still ironic that this is one of the great problems of Starlink right now).

The germ of today’s satellites

For several years these two satellites and others like PAGEOS were used both for communications and for experiments and data collection from the atmosphere. Passive globe-shaped satellites enabled transatlantic communications and created triangulation mapping among other functions.

In a way, they were an impulse to bet on satellite communication. Until then, operators saw the future only in terrestrial infrastructure. However, these types of projects increased interest in air and satellite communications.

Seen in perspective and with current technology, we understand why these satellites did not finish triumphing. They were large, their communication was passive, limited and with a useful life in the open air of the atmosphere. Later satellites were active satellites, which collected specific data and sent it to specific points, they are the current satellites.


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