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Comment by syntaxing | Hacker News Reader

How much of a lag is there in the data transmission? I guess that should correspond to how many light years it is away? How does the probe know which direction to send the data? I have so many questions! I gotta watch that documentary and listen to the podcast people are suggesting here!

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The current one way transmission times are 20 hours and 5 minutes to Voyager 1 and 16 hours and 38 minutes to Voyager 2: https://voyager.jpl.nasa.gov/mission/status/

The probes use a star tracker to determine their orientation (they apparently look for the sun and one other star). I assume they keep track of their expected position in the solar system, and this is fine-tuned with updates from the ground station. If you have position and orientation, you can compute where the Earth should be at the current time and point the antenna in that direction.

Also, at their distance, they don't really have to be that close in aiming. Their beam is plenty wide by the time it reaches Earth.

All with 1970s technology, simply amazing stuff.

"Light years" is a bit optimistic. Voyager 1 is about 20 light-hours away (144 times further from the sun than we are).

https://voyager.jpl.nasa.gov/mission/status/

you know, it's pretty damn incredible that we've sent little tiny space probes out of our solar system and they can still talk to us. sometimes i like imagining this tiny ball of circuits floating in space talking to its home planet and it just boggles my mind.

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