Title. Also maybe more extreme, but how is the Mars Rover sending pictures to earth. I cannot grasp how this works over such a long distance.
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Radio, no big mystery there.
Well, a little mystery perhaps, what is often overlooked is just what kind of antennae are used to receive the signals from distant and low powered devices across solar system [https://spacenews.com/increasing-demands-putting-pressure-on-deep-space-network/](https://spacenews.com/increasing-demands-putting-pressure-on-deep-space-network/) check the little service buildings next to antennae for scale.
Size and directionality of antenna make a massive difference for how far away you can extend a connection. Take common wifi devices and replace the tiny antennas with something more like satellite TV dishes and you can basically have wifi connection however far you can find line of sight, it’ll work for hundreds of km if you point the antennas to each other. And that’s with wifi which is very demanding because of how much data it pushes through.
Accept lower data rates and you can reduce the demands for the antenna and transmitter power significantly. With LoRa its possible to have satellite connection with small undirected antennas and very low power transmissions, it’s just that the datarates are puny, nothing like what you have for wifi [https://harmvandenbrink.medium.com/tracking-and-receiving-messages-from-satellites-with-lora-afafd875e005](https://harmvandenbrink.medium.com/tracking-and-receiving-messages-from-satellites-with-lora-afafd875e005)
Now if you combine large highly directional antennas, puny data rates and fairly high powered transmission, then Voyager probes can phone home no problem.
Even more capable than radio would be laser comms, your typical handheld laser pointer can be seen from space with a naked eye if you point it right. That’s because it’s directionality is a lot higher than what a radio antenna can manage, you don’t need to put out much power if it’s all going the right way.
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