May 17th – Baby I’m a Star

Today’s factismal: It is National Telecommunication Day. Go call your mother!

Today is National Telecommunication Day, celebrating 58 years of communicating with satellites. Amazingly enough, we are actually still communicating with the satellite that launched the telecommunications revolution. named Vanguard 1, it was launched on May 17, 1958 and was supposed to last just six years; it is now the oldest man-made satellite in orbit. This little wonder weighs just three pounds, is just over 6.4 inches across, and goes around the Earth nearly eleven times a day. Since it was put into orbit, it has seen more than 238,000 sunrises; if you go outside today, you might see it rise yourself.

An engineering spare for the Vanguard 1 satellite (Image courtesy NASA)

An engineering spare for the Vanguard 1 satellite (Image courtesy NASA)

Vanguard 1 had three main missions. The first, and most important, mission was restoring the nation’s confidence in their space program. Though the US had managed to launch a satellite into orbit (Explorer 1 on January 31), it had started to tumble almost right away. Worse, there had been several very public failures including one rocket explosion shown live on television. A successful launch was essential to demonstrate that the US could keep up in the “space race” that had developed.

An artist's deception of what Vanguard 1 looks like in orbit (Image courtesy NRL)

An artist’s deception of what Vanguard 1 looks like in orbit
(Image courtesy NRL)

Second, Vanguard was intended to bolster interest in science and engineering. In order to do that, it had two radio transmitters that broadcast on ham radio frequencies. Ostensibly, the beacons were intended to help geophysicists accurately determine the shape of the Earth by allowing them to measure the slight changes in Vanguard’s speed caused by changes in the topography below; practically, they encouraged young students to become engineers and scientists by allowing them to hear the satellite as it went overhead. (This mission is continued today with the AO-51, AO-27, and SO-50 satellites.) By communicating with people on the ground around the globe, Vanguard 1 started the telecommunications revolution that led us through the Echo 1 satellite,  (the first satellite dedicated to communication), Elvis’ Aloha From Hawaii (the first international live satellite concert with a single performer), and into today’s interconnected world.

Engineers working on the vanguard 1 satellite before launch (Image courtesy NASA)

Engineers working on the vanguard 1 satellite before launch
(Image courtesy NASA)

Vanguard 1’s third mission was also the most counter-intuitive to non-physicists. Vanguard 1 was intended to allow scientists to measure the density of the atmosphere in outer space. Though most non-scientists believe that there is a hard boundary between outer space and the atmosphere, in truth it is more of a vaguely defined zone. As you go up, the atmosphere becomes less and less dense but never entirely stops. As a result, satellites that orbit close to the Earth (e.g., Vanguard 1, the International Space Station) are slightly slowed down by atmospheric drag. By measuring the amount of slowdown, physicists are able to determine the density of the upper atmosphere.

Installing Vanguard 1 on the rocket that would take it into orbit (Image courtesy NRL)

Installing Vanguard 1 on the rocket that would take it into orbit
(Image courtesy NRL)

And the results were certainly surprising. Originally, the mission planners had thought that the upper atmosphere was so thin that the satellite would orbit for 2,000 years. Instead, it is dense enough that Vanguard 1 will fall to Earth after only 240 years (185 years from now). Those results have helped with the design of new satellites and even inspired one private space venture.

If you’d like to get a little inspiration of your own but don’t want to build a ham radio station, then why not use the SatCam app? This smartphone app uses pictures that you take of clouds to “ground-truth” satellite data so that scientists can get a better idea of what the satellites are really seeing. In return for your photos, the app shows you what the satellite saw as it passed overhead.
http://satcam.ssec.wisc.edu/

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