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Aperockyyesterday at 3:45 PM9 repliesview on HN

Not useful, because the signal are too weak to be picked up probe to probe.

On earth, the tiny signal from Voyager at this distance is picked up by dish the size of a football field; same with sending of the signal.


Replies

glensteinyesterday at 4:51 PM

Very true insofar as it's a description of Voyager communications. Voyager was 1970s radio engineering. Radio signals spread wide, so you need a big dish to catch it. These days we are using lasers, and laser divergence is several orders of magnitude smaller. And regardless of tech, relay enforces a minimum distance for any signal to spread.

pseudocomposeryesterday at 4:09 PM

This is a silly counterexample - why would we launch them that far apart? It’s a terrible idea for multiple reasons. We’d want them close together, with some redundancy as well, in case of failures.

What dish size would be required for a “cylindrical/tubular mesh” of probes, say, 1AU apart (ie Earth-Sun distance)? I’m pretty sure that would be manageable, but open to being wrong. (For reference, Voyager 1 is 169AU from Earth, but I have no idea how dish size vs. signal strength works: https://science.nasa.gov/mission/voyager/where-are-voyager-1...)

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malfistyesterday at 4:03 PM

The dish isn't the size of a football field, it's a 70 meter dish (football field is 110 meters), it can however, transmit at 400 kilowatts of power

boznzyesterday at 6:44 PM

Unlike the other comments I actually agree, physics has not changed since the 1970's, even the most focused laser and detector would need to be positioned perfectly to where the next probe would be, and with the nearest star 4 light years away we would be talking a chain of dozens, any of which may fail some way. The probes would also likely be small, cell-phone sized, power restricted, and difficult to shield (you couldn't just throw in the latest wiz-bang 2025 electronics as it all has to be hardened to work multiple decades) Best is a big, transmitter and good receiver one end.

rootnod3yesterday at 4:19 PM

You could send a good amount of small probes and make them become the big antenna dish basically. As long as you cover the bases, you can have layers of "big antenna dishes" in onion layers.

JumpCrisscrossyesterday at 4:39 PM

> the tiny signal from Voyager at this distance is picked up by dish the size of a football field

Lots of small fishes can resemble a large fish.

jcimsyesterday at 4:03 PM

Laser communication could potentially address some of those issues.

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nntwozzyesterday at 3:55 PM

What if the probes carry smaller probes left behind at specific intervals that act as repeaters?

These baby probes could unfold a larger spiderweb antenna the size of a tennis court.

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BobbyTables2yesterday at 4:07 PM

Football field might even be too small…

Wasn’t Arecibo used for Voyager?

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