Eli5: Are satellites really ‘beeping’ and why?
In: Engineering
No, not in an audible sense.
The first satelite, Sputnik, launched by the Soviet Union in the 50’s sent out a ping that could be picked up on radio to prove it was there.
The trope of satellites beeping comes from that first one.
The first satellite launch, Sputnik, had a simple radio circuit and battery that would send out regular beeps on the radio if you tuned inn to it. This was to prove that they had actually launched a satellite into orbit. The implecation being that they would therefore also be able to launch any nuclear weapon to anywhere in the world. The sounds from Sputnik is the classical satellite beeping sound you hear in movies and tv shows and have become a classic trope.
However similar radio transmissions continued to be used by sattelites but now modulated with data collected by the satellites instruments. So they would not sound like a clear beep but rather like random noise like from a classical modem. You can hear some of this in for example recordings of 60s space flights. Not all recordings include them but those that do will have the sound interupted by what sounds like random static but they are at regular intervals, just like the beeping Sputnik. If you were to analyze this static you would be able to extract telematry data from it.
Sattelites do still transmit telematry data although with modern techniques they use different modulations and do it at different intervals then the early satellites. And they are able to be encrypted and digitally signed so that others can not interfering with their signals.
Nope. A speaker would be extra weight and entirely pointless since sound can’t propagate in space.
It costs a lot of money to launch a satellite, every gram of weight costs money, you wouldn’t put a speaker on it since it would be a waste of weight/space.
In TV and movies they want to show “hey this is a satellite and it’s transmitting” so they add sound effects
One place you **will** find a speaker in space is Elon’s Tesla Roadster, an entire commercial model car floating around in orbit, the car’s stereo system is permanently looping the song “Space Oddity”.. but you can’t hear it since sound doesn’t propagate in space.
This idea comes from our first satellites in space. Sputnik transmitted morse code for “hi” 4 dots and then 2 dots. “…. ..” Unfortunately our recordings aren’t very clear so it just sounds like a beep. As more satellites were launched they begin to study different aspects of space. They transmitted their data in analog as a series of beeps and tones. [https://youtu.be/MjVorX1YVng](https://youtu.be/MjVorX1YVng)
Some modern satellites transmit analog data and series of beeps and tones. NOAA weather satellites can be received by a basic radio scanner and using free software you can receive pictures from the satellites as it passes overhead.
[https://youtu.be/h4Y0EUHFaXg?t=360](https://youtu.be/h4Y0EUHFaXg?t=360)
[https://youtu.be/PWWGDL5tC_I](https://youtu.be/PWWGDL5tC_I)
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