sixty years ago, the Massachusetts Institute of Technology made television history by sending itself a broadcast message. The image, the first to be shown on US national television using a satellite feed, was a rather self-referential set of three letters: MIT
If you’re thinking it’s 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 itself: Send the image from one of the US’s national security research laboratories. institute in California to a receiver 2,700 miles away in Massachusetts. In doing so, they fundamentally altered the way the world viewed television long before Netflix came on the scene.
The problem with television
Today, people can watch the same thing on TV at the same time all over the world. But until the 1960s, it was impossible. Six decades ago, the development of satellite communications allowed us to transmit television beyond the horizon and beyond the ionosphere. The way satellite communications work is that they receive a data transmission from Earth and reflect it back to a receiver located in a separate area of Earth.
The idea of using a satellite to communicate messages across the Earth had its genesis in 1946 when scientists attempted to use the Moon as a passive satellite to improve long-distance communication.
Before this, broadcasters used to use radio waves to send messages over a distance, but these cannot extend beyond the horizon. But some scientists noticed that long-distance radio signals occasionally hit an ionized section of Earth’s atmosphere, called the ionosphere, before bouncing back to Earth. According to the theory, a satellite could apparently transmit information beyond the ionosphere and return it to the intended receiver on Earth. But first, we needed satellites.
The first satellites in the world.
In 1957, Russia launched Sputnik 1, the first artificial Earth satellite. Then, in 1958, several scientists at Bell Telephone Laboratories devised an experiment using glowing balloons as satellites to measure the reflective properties of the atmosphere. They hoped that this project would evolve to allow scientists to send data across the oceans.
Meanwhile, other scientists designed antennas large enough to pick up any signal transmitted by satellites. It so happened that it was located in one of the facilities of the Jet Propulsion Lab in southern California in the Mojave desert.
At the same time that scientists at Bell Labs developed their reflective satellite balloon experiment, the US founded NASA. JPL became part of NASA, and together with Bell Laboratories, these institutions launched America’s first satellite communications project in January 1959, Project Echo.
Project Echo was a ‘pioneer’ mission, which means it’s a bit of a playground; it’s a great mission that explores 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 really work. Some variables Project Echo scientists played with were how the shape, size, material, reflectivity, and aerodynamics of the 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 earliest launch rockets used to initiate orbits. On the same day, when Echo 1 was within range, the first satellite message was sent from Florida to Bell Labs in New Jersey.
How Echo 1 made history
The mission was a stunning success. He was successful in each of his five goals. He demonstrated that two-way communication was possible via a satellite-facilitated telephone call in August 1960. He then demonstrated that it was possible to transmit terrestrial signals using reflection on April 24, 1962, 60 years ago. Echo also exceeded its other goals to study atmospheric drag and variations in air density and the ionosphere.
The Echo spacecraft does not look like what we think of as satellites today. Known as “satellites” by the scientists involved in the project, the Echo spacecraft were large, nearly flat, circular disks covered in material—essentially, a balloon.
Echo 1 had a diameter of 98 feet, just under a third the size of the International Space Station. The instrument itself weighed 157 pounds when it was released. On land, 40,000 pounds of air were required to fill the balloon. In space, however, only a few pounds of air were required to fill the balloon due to the lower surrounding pressure.
After the spacecraft left the atmosphere, its disk inflated in orbit. The balloon material was essentially a shiny surface for reflecting data-bearing waves in space, so bright 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 today to keep marathon runners and wayward mountaineers warm.
Echo 1 spent its first year in orbit transmitting voice recordings. It was a struggle to transmit the comparatively weak signal of the voice recordings over the background noise that filled the space between the source of the recordings and the satellite. So it was a revelation when on April 24, 1962, Echo 1 successfully broadcast television; television, of course, involves images, which can be even more difficult to convey above the noise.
“Echo 1 was successful in demonstrating the simple fact that it was possible to transmit a message over a long distance between two locations 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 also served on the NASA Advisory Council and the Columbia Accident Investigation Board.
“What was needed was onboard equipment to process the incoming signal and then retransmit it back to Earth. That capability was demonstrated in 1962 by the Telstar satellite”, he adds.
Echo’s Legacy 1
President Kennedy on Telstar.
In late 1962, the 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 the Earth. The Telstar was responsible for the first transatlantic transmissions, from stations in the US, Canada and Europe. The first commercial communications satellite was launched soon after, in 1965: Intelsat 1.
Since then, fixed (as opposed to orbit) satellite technology has enabled continuous coverage of part of the Earth’s surface. In the 1990s, the advent of mobile phones and cellular radio started a boom in satellite communications, growing at more than 20 percent a year, according to Andrew J. Butrica, author of Beyond the Ionosphere: Fifty Years of Satellite Communication.
Today, Butrica writes, satellite communications are largely focused on the development of a global satellite system, such as GPS. Ongoing geopolitical tensions also mean that some territories are seeking to create their own global satellite systems as a means of gaining strategic advantage: Russia and China, for example, offer each other equipment to study global satellite communications, but do not collaborate on it. your investigation. .
There are tens of thousands of satellites in orbit around the Earth; we depend on them for communications, maps, television, the Internet, and more. In 60 years, satellite communications have come a long way from that image of “MIT” on a black-and-white television screen (and fortunately, so has television entertainment).