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This is one piece of the puzzle certainly if man is going to look beyond Earth. If a Mars colony for instance was indeed established there would be some interes
by leonroy 9y ago
This is one piece of the puzzle certainly if man is going to look beyond Earth. If a Mars colony for instance was indeed established there would be some interesting data transfer and communication problems to work out in order to effectively transfer information and knowledge:
Mars at its closest is 58 million km (36 million miles) away from Earth. It varies though and can be as far as 100 million km (63 million miles).
That's about 192 seconds to 333 seconds of latency which an electromagnetic signal would have to traverse each way.
I can't dig up what the maximum permissable latency of a TCP based network is but I'd imagine 5 minutes exceeds it. Even if you created a network in which a 5 minute latency is acceptable your throughput would be ridiculously low.
There would likely have to be proxies and relays along the way to ensure acceptable performance but in itself the problem would require a lot of resources to effectively solve. I wonder if SpaceX is actively looking at offworld comms or if they hope organizations like Arch will attempt to solve it. Either way, an exciting time to be an engineer!
- namirez 9y agoActually, Mars and Earth can be as far apart as 400 million km, which amounts to a latency of 1333 sec.
- Robotbeat 9y agoAlready a thing: https://en.wikipedia.org/wiki/Interplanetary_Internet https://en.wikipedia.org/wiki/Interplanetary_Internet
- Xeoncross 9y agoWouldn't optical transmission (light) be much better? Both planets would have multiple satellites that would be the proxies between planets as one of them would always be able to "see" the others. Alignment would be tricky, but seems more promising with throughput.
- rohit2412 9y agoThey said " electromagnetic signal ". Isn't light an electromagnetic signal?
- jacquesm 9y agoIP has been implemented over carrier pigeons. But TCP maximum segment lifetime is 120 seconds.
- greenhouse_gas 9y ago> It varies though and can be as far as 100 million km (63 million miles). It could get worse. Since at that point, the Sun is smack in between the earth and mars, so for a few days you can't get _any_ signal through. You'd have to bounce it off some third satellite in solar orbit (like a triangle). See https://space.stackexchange.com/a/18972 https://space.stackexchange.com/a/18972
- pzxc 9y agoIt's even worse than that. The earth is 93 million miles from the sun (1 AU), so when Mars is on the opposite side of the sun it's at least 180 million miles away, with the sun in the way. The numbers expressed by GP for how far Earth is from Mars is actually referring to how far Earth's orbit is from Mars' orbit, not the distance of the planets themselves at various positions in their orbits.
- skellera 9y agoFor normal internet use that doesn't need instant changes, caching relays would be pretty interesting. Kinda like how Netflix has servers at ISPs. So you would get "instant" access to things but it would be behind. The Expanse (book/tv) does an interesting bit when talking with people as close as the moon. Talking over each other and stuff would be something that would we'd have to get used to.