Not sure if I used the right tag but I saw something about a space probe from the 70s malfunctioning and spouting gibberish that nasa managed to repair, but how do probes that are so incredibly far away transmit data back to earth?
In: Planetary Science
There’s nothing between us. So we just send radio communication, and use a very focused antenna listening to a very specific frequency
There are some very large and powerful satellite dishes here on Earth that listen for data from the probes, as well as send them data.
One of the nice things about space in regards to sending signals is that space is pretty darn empty, so if you send radio waves out into space, there’s a good chance they’re going to travel very far before something blocks them. So we’ve got nice clear line of sight between those probes and the Earth.
The big problem is that radio waves spread out as they travel, so the amount of signal that gets to a probe that’s really far away (and the amount that gets from that probe back to Earth) is only a small fraction of the radio waves that have been sent. But that’s what the huge and powerful satellite dishes are for. We also know fairly precisely where the Earth is and where the probes are, so it’s possible to aim the dishes for maximum effectiveness.
there is “nothing” in space; so radio/light can travel incredibly long distances.
since we know where the object is we can focus the signal for even greater reliability and successful communication
We use [absolutely enormous satellite dishes](https://en.wikipedia.org/wiki/NASA_Deep_Space_Network). Think of how big the satellite dish for satellite TV is. Now imagine one 70m across!
Being so big, the dishes amplify the signal enough that we can communicate with the probe from so far away.
[NASA lets you see what these dishes are talking to](https://eyes.nasa.gov/dsn/dsn.html), looks like it’s listening to Voyager 1 in Canberra right now (VGR1)
The same way Dish Antennas communicate with satellites.
When the ground stations need to communicate with a faraway probe, lets say Voyager, cause it is cool, they send a directed signal with a frequency of around 2.3Ghz (Infrared) towards the calculated future location of the satellite considering the time it takes for light to reach it. The biggest barrier the signal faces is our own atmosphere. Once the atmosphere is crossed, there is nothing really stopping the signal from reaching the Voyager. The Voyager can respond similarly by directing its signals to the future calculated location of earth.
The distance of a satellite from earth plays a much smaller role compared to the composition of the atmosphere around the ground station that day. Once you go through the atmosphere, the only problematic part is the dispersion of light, which can be remedied through strong directed signals and stronger receivers.
Other people have covered the big poweful satellite dishes but even then we have to sens the instructions multiple times to make sure they recive the complete message.
It’s a bit like talking to your slowly goimg deaf grandad. You speak louder than normal and repeat what you say a lot.
The last bit i’m not sure how to ELI5 but the message protocols used have some error correction built it that they can correct not fully received messages using mathematics.
Pretty much the same way that you communicate with your friends when you phone them. As long as there are no obstacles, radio waves will go on and on forever, so it doesn’t matter if the probe is in the next room or in the next galaxy. The waves will just take a long ass time to get there and back and the antennas have to be ridiculously big.
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