The unexpected consequences of Sputnik

The unexpected consequences of Sputnik

On Monday, October 4, 1957, the Soviet Union put Sputnik into orbit: the first artificial satellite in history . It was a metallic sphere 50 centimeters in diameter and four antennas that emitted a "beep" (a 20 MHz signal) every few seconds. That "beep" was detectable from Earth. The news made the front page of every newspaper in the world. Two young physicists named William Guier and George Weiffenbach read the news in the cafeteria of the Maryland Department of Applied Physics and began to discuss the possibility of detecting that signal . They suspected that all this was not real, but was a hoax of the Soviet propaganda machine. Weiffenbach was doing his doctorate in microwave spectroscopy and had a receiver available in his office. The two colleagues went to work and by mid afternoon they were already hearing that "beep". It was not a hoax of Soviet propaganda: that sign was real .

It was an incredible situation: sitting in a room in a Maryland suburb, listening to man-made signals from space . The news spread and scores of people started pouring into Weiffenbach’s office. The two young men realized that what they were doing was historically important, so they began to record the signals and the moment they were received. They soon found out that by Doppler effect they could tell if the satellite was approaching or moving away from their laboratory as well as the speed at which it was going. And even more, by analyzing the change in the Doppler effect they could know the point where it was closest to the laboratory.

Almost by accident they came up with the technique to calculate the trajectory of the satellite . Lots of colleagues from the lab joined them, pushing the research forward, proposing improvements. The director approved the funds for those calculations to be entered into a new computer called UNIVAC. In a few months they already knew the orbit of the satellite only starting from that "beep".

The reverse problem

The Director of the Physics Department, Frank McClure, called them into his office and proposed the reverse problem. That is, if they could know the orbit from a receiving point on the Earth of an emitting object in space, could the position of a receiving object on Earth that captures the signal from a satellite be determined by knowing in advance the orbit of said satellite? ? I wanted to know as soon as possible. After a few days of intense calculations, they came back with the answer: " the inverse problem ," as they called it, had a solution.

Guier and Weiffenbach soon learned why that problem was so important to McClure. The US Army was working on the Polaris program. It consisted of being able to launch nuclear missiles from submarines. It is easy to calculate the trajectory of a missile if it is launched from a silo in Alaska, but from a mobile platform such as a submarine, not knowing where it is in the middle of an ocean is not so simple.

But just as sailors had used the stars to navigate for thousands of years, the military was going to put their artificial stars with satellite technology. Three years later the Americans had already put five satellites into orbit.

Over time, that location system would come to be known as the Global Position System : the GPS.

We owe a lot to those talks over coffee cups from the scientists.

Source | Steven Johnson , Where good ideas come from: the natural history of innovation . Photo | Pixabay