sixty years ago, the Massachusetts Institute of Technology made television history by sending itself a broadcast message. The image, the first-ever aired on US national television using a satellite broadcast, was a rather self-referential set of three letters: MIT
If you think this is a publicity stunt, think again.
On April 24, 1962, MIT worked with the US Air Force to use the Echo 1 communications satellite to send a message to each other – sending the image from one of the institute’s national security research labs. in California to a receiver 2,700 miles away in Massachusetts. In doing so, they fundamentally changed the way the world watched TV long before Netflix came onto the scene.
The problem with TV
Today, people can watch the same thing on TV at the same time across the world. But until the 1960s, that was impossible. Six decades ago, the development of satellite communications allowed us to broadcast television beyond the horizon and the ionosphere. The way satellite communications work is that it receives a data transmission from the Earth and sends it back to a receiver placed in a separate area of the Earth.
The idea of using a satellite to communicate messages across the Earth originated in 1946 when scientists tried to use the Moon as a passive satellite to improve long-range communication.
Prior to this, broadcasters typically used radio waves to send messages over a distance, but these cannot extend beyond the horizon. But some scientists have noticed that long-distance radio signals sometimes hit an ionized section of Earth’s atmosphere, called the ionosphere, before bouncing back to Earth. According to the theory, a satellite could apparently relay information beyond the ionosphere and send it back to the desired receiver on Earth. But first, we needed satellites.
The world’s first satellites
In 1957, Russia launched Sputnik 1, the first artificial Earth satellite. Then, in 1958, several scientists at Bell Telephone Laboratories pondered an experiment using bright balloons as satellites to measure the reflective properties of the atmosphere. They hoped this project would evolve to allow scientists to send data across the oceans.
Meanwhile, other scientists have designed antennas large enough to pick up all signals relayed by satellites. He happened to be at one of the Jet Propulsion Lab facilities in Southern California, in the Mojave Desert.
At the same time Bell Labs scientists developed their reflective satellite balloon experiment, the United States founded NASA. JPL became part of NASA, and together with Bell Laboratories, these institutions launched the United States’ first satellite communications project in January 1959, Project Echo.
Project Echo was a “scout” mission, which means it’s a bit of a playground; it’s a big mission exploring a variety of concepts to refine in the direction of future missions. It was a project that allowed scientists to experiment and push the boundaries of what was already known about satellite communication to determine what would actually work. Some variables Project Echo scientists played with were how the shape, size, material, reflectivity and aerodynamics of satellites affected and limited their performance. The mission was never intended to become a global satellite communications network.
The Echo 1 spacecraft was first launched on August 12, 1960 from Cape Canaveral, Florida via a rocket called the Thor-Delta, one of the first rockets used for launches used to initiate orbits. On the same day, when Echo 1 was in range, the first satellite message was sent from Florida to Bell Laboratories in New Jersey.
How Echo 1 made history
The mission was a resounding success. He succeeded in each of his five objectives. He demonstrated that two-way communication via a satellite-facilitated telephone call was possible, in August 1960. Next, he proved that it was possible to transmit signals to the ground using reflection on April 24, 1962, there is 60 years. Echo also broke its other goals of studying atmospheric drag and variations in air density and the ionosphere.
The Echo spacecraft is unlike what we think of as satellites today. Called “satelloons” by the scientists involved in the project, the Echo spacecraft were large, nearly flat, circular disks covered in material — essentially, a balloon.
Echo 1 was 98 feet in diameter, just under a third the size of the International Space Station. The instrument itself weighed 157 pounds when launched. On the ground, it took 40,000 pounds of air to fill the balloon. In space, however, only a few pounds of air were needed to fill the balloon due to the lower surrounding pressure.
After the spacecraft left the atmosphere, its disc swelled in orbit. The balloon material was essentially a shiny surface to reflect waves containing data back into space – so shiny that it was visible to the naked eye on the Earth’s surface. In fact, it was made of mylar, the same material as the silver blankets used to keep wayward marathon runners and mountaineers warm today.
Echo 1 spent its first year in orbit transmitting voice recordings. It was a struggle to transmit the relatively weak signal of the voice recordings over the din of background noise filling the space between the source of the recordings and the satellite. So it was a revelation when on April 24, 1962, Echo 1 managed to successfully transmit television – television, of course, involves pictures, which can be even more complicated to relay over noise.
“Echo 1 successfully demonstrated the simple fact that it was possible to relay a long-distance message between two places on Earth by bouncing it off an orbiting object. But it was a dead-end technology,” says John Logsdon, professor emeritus and founder of the Space Policy Institute at George Washington University. Logsdon has also served on the NASA Advisory Board and the Columbia Accident Investigation Board.
“What was needed was on-board equipment to process the incoming signal and then relay it back to Earth. This capability was demonstrated in 1962 by the Telstar satellite,” he adds.
The legacy of Echo 1
President Kennedy on Telstar.
In late 1962, communications giant AT&T launched Telstar, the first active communications satellite – Echo 1 paved the way. Like Echo 1, Telstar was launched from Cape Canaveral on a Thor-Delta rocket, and although it is no longer active, it continues to orbit Earth. The Telstar was responsible for the first transatlantic broadcasts, from stations in the United States, Canada and Europe. The first commercial communications satellite launched soon after, in 1965, Intelsat 1.
Since then, fixed (as opposed to orbiting) satellite technology has enabled continuous coverage of part of the Earth’s surface. In the 1990s, the emergence of cell phones and cellular radio initiated a boom in satellite communications – growing at more than 20% per year, according to Andrew J. Butrica, author of Beyond the ionosphere: fifty years of satellite communication.
Today, writes Butrica, satellite communications are largely centered on the development of a global system of satellites – like GPS. Ongoing geopolitical tensions also mean that some territories are trying to create their own global satellite systems to gain a strategic advantage – Russia and China, for example, offer each other equipment to study global satellite communications, but they do not collaborate in their research. .
There are tens of thousands of satellites orbiting the Earth – we depend on them for communication, mapping, television, internet, etc. In 60 years, satellite communications have come a long way from that image of “MIT” on a black-and-white television screen (and luckily, television entertainment too).