5 ms·

IMO the most likely solution to interplanetary networking is to throw tons of datacenter and compute that's anywhere more than a few light-seconds from the near

IMO the most likely solution to interplanetary networking is to throw tons of datacenter and compute that's anywhere more than a few light-seconds from the nearest existing datacenter, then use something along the lines of IPFS to perform data synchronization between planets.

bigfatkitten 1y ago
Despite the name, IPFS has no properties that make it suitable for this application. It’s very bandwidth intensive and isn’t designed with latency or disruption tolerance in mind.
macintux 1y ago
How would that work to, say, Mars? Have satellites filling many, many orbits between the two planets?
- cjtrowbridge 1y ago
  We already have an interplanetary internet called the NASA Deep Space Network. Understanding it's limitations and challenges is a good way to start thinking about this.
- BizarroLand 1y ago
  Nah, nothing that extreme. The broadcast range and bandwidth of even current technology in space could handle a huge amount of fairly rapid data transfer between the two planets. It would be more like a handful of satellites, some orbiting earth, some orbiting mars, and then a handful of relay satellites serving as intermediaries. Don't count on playing e-sports competitively, though. The lag under ideal conditions would be insane, about 2.5 minutes each way (when the planets are "only" 40 million kilometers apart), but with repeaters and overhead probably closer to twice that.
  - macintux 1y ago
    The comment was a few light-seconds. That's a lot of hops to Mars to fill to sustain that coverage year-round.
    - snickell 1y ago
      The distance between earth and mars varies between 150 and 2000 light seconds.
      - macintux 1y ago
        But carpeting that distance across the entire volume of space between the planets with data centers every few light-seconds apart seems ambitious. A hundred or more data centers in space? > throw tons of datacenter and compute that's anywhere more than a few light-seconds from the nearest existing datacenter I think I'm misinterpreting the comment.
        BizarroLand 1y ago
        It's like the transatlantic internet cable. One really beefy interconnect is more than enough for two halves of the planet to talk. We wouldn't need to blanket the solar system in data centers to be able to communicate with other planets. We would only need enough connections so that no matter where in their respective orbits they are, there is a line of radio "sight" that is clear enough for high bandwidth communications to work. I don't have access to the specifics, but I imagine something between 5 and 10 satellite data centers orbiting the sun in between earth and mars would be enough to maintain communications with minimum delay regardless of when in the solar year the comms take place.
        macintux 1y ago
        At their maximum separation, Mars & Earth are about 20 minutes apart. If we had 10 satellite data centers all in perfect alignment (disregarding the sun, which obviously makes a hash out of things) they'd still each be 2 minutes apart. Once you take into consideration the sun, plus the fact that the you'd need to cover the full disk to keep all data centers within a few minutes of another one in an unbroken chain back to both planets, I just don't get the math involved here. But, I'm also terrible at both math and visualization, so I readily concede I may be missing something obvious.
knome 1y ago
there's a lot of interesting problems just in the networking. if it took four years for a message to cross the void from where you are to the recipient, you certainly wouldn't want to wait a full eight years to see they didn't send a receipt message and only then retransmit. eight years is some awful latency. you'd probably want to send each message at something like a fibonacci over the months. so, gaps of (1, 1, 2, 3, 5, 8, etc) would mean sending the message on months (1, 2, 4, 7, 12, 20, 33, etc) until you got a confirmation message that they had received it. they would similarly want to send confirmations in the same sort of pattern until they stopped receiving copies of that message. spreading the resends out over time would ensure not all of your bandwidth was going to retransmissions. you'd want that higher number of initial transmissions in hopes that enough of the message makes it across the void that they would have started sending receipts reasonably close to the four years the initial message would take to get there. if you had the equivalent of a galactic fido-net system, it could be decades and lifetimes between messages sent to distant stars and messages sent back.
- furyofantares 1y ago
  Wouldn't you want to completely saturate your bandwidth? Just always be transmitting whatever message has been transmitted the least.
  - knome 1y ago
    that would probably depend on how much power it takes to send the messages, how much actual usable bandwidth you could manage over the distances involved, and how much data you want to send. if it takes a large amount of energy to send the data, we probably wouldn't want to run the equipment all the time. strong pulses would let the equipment cool down or recharge capacitor banks or whatever during downtime. interstellar dust and other debris floating through space could cause interference, not to mention radiation from everything else around us, and our own sun shining right next to our little laser. might want to move the laser out onto pluto or something to avoid having it right up against the sun.
- scottyah 1y ago
  and you'd probably want to take orbits/vectors into account, a djikstra-esque algorithm where the distances change is crazy. Also, our signals are usually going very short distances very quickly and are very protected from solar/cosmic waves by the ionosphere. What kind of data loss could you get transmitting in open space across vast distances and time?
jvanderbot 1y ago
I agree! This was my obsession when I worked at JPL, unfortunately the answer was usually "no mission will sacrifice their budget for reusable assets". You'd need a mission whose purpose is to emplace compute stations. That's why we can't have nice things.
r14c 1y ago
you'd probably want a different protocol than IPFS for that application. managing a DHT with extremely high latency isn't going to work very well. something like named-data networking would probably work better since the transmitter can know 1. exactly what prefixes need to be buffered based on the received interest messages from deep space 2. exactly which data rate is possible at any given time 3. exactly how much data needs to be sent from the buffer in each transmission optimizing for high latency really pushes your design choices around compared to our comparatively very low latency uses here on earth. its pretty interesting to think about.
unit149 1y ago
[dead]

bigfatkitten 1y ago

Despite the name, IPFS has no properties that make it suitable for this application. It’s very bandwidth intensive and isn’t designed with latency or disruption tolerance in mind.

macintux 1y ago

How would that work to, say, Mars? Have satellites filling many, many orbits between the two planets?

cjtrowbridge 1y ago
We already have an interplanetary internet called the NASA Deep Space Network. Understanding it's limitations and challenges is a good way to start thinking about this.
BizarroLand 1y ago
Nah, nothing that extreme. The broadcast range and bandwidth of even current technology in space could handle a huge amount of fairly rapid data transfer between the two planets. It would be more like a handful of satellites, some orbiting earth, some orbiting mars, and then a handful of relay satellites serving as intermediaries. Don't count on playing e-sports competitively, though. The lag under ideal conditions would be insane, about 2.5 minutes each way (when the planets are "only" 40 million kilometers apart), but with repeaters and overhead probably closer to twice that.
- macintux 1y ago
  The comment was a few light-seconds. That's a lot of hops to Mars to fill to sustain that coverage year-round.
  - snickell 1y ago
    The distance between earth and mars varies between 150 and 2000 light seconds.
    - macintux 1y ago
      But carpeting that distance across the entire volume of space between the planets with data centers every few light-seconds apart seems ambitious. A hundred or more data centers in space? > throw tons of datacenter and compute that's anywhere more than a few light-seconds from the nearest existing datacenter I think I'm misinterpreting the comment.
      - BizarroLand 1y ago
        It's like the transatlantic internet cable. One really beefy interconnect is more than enough for two halves of the planet to talk. We wouldn't need to blanket the solar system in data centers to be able to communicate with other planets. We would only need enough connections so that no matter where in their respective orbits they are, there is a line of radio "sight" that is clear enough for high bandwidth communications to work. I don't have access to the specifics, but I imagine something between 5 and 10 satellite data centers orbiting the sun in between earth and mars would be enough to maintain communications with minimum delay regardless of when in the solar year the comms take place.
        macintux 1y ago
        At their maximum separation, Mars & Earth are about 20 minutes apart. If we had 10 satellite data centers all in perfect alignment (disregarding the sun, which obviously makes a hash out of things) they'd still each be 2 minutes apart. Once you take into consideration the sun, plus the fact that the you'd need to cover the full disk to keep all data centers within a few minutes of another one in an unbroken chain back to both planets, I just don't get the math involved here. But, I'm also terrible at both math and visualization, so I readily concede I may be missing something obvious.

knome 1y ago

there's a lot of interesting problems just in the networking. if it took four years for a message to cross the void from where you are to the recipient, you certainly wouldn't want to wait a full eight years to see they didn't send a receipt message and only then retransmit. eight years is some awful latency. you'd probably want to send each message at something like a fibonacci over the months. so, gaps of (1, 1, 2, 3, 5, 8, etc) would mean sending the message on months (1, 2, 4, 7, 12, 20, 33, etc) until you got a confirmation message that they had received it. they would similarly want to send confirmations in the same sort of pattern until they stopped receiving copies of that message. spreading the resends out over time would ensure not all of your bandwidth was going to retransmissions. you'd want that higher number of initial transmissions in hopes that enough of the message makes it across the void that they would have started sending receipts reasonably close to the four years the initial message would take to get there. if you had the equivalent of a galactic fido-net system, it could be decades and lifetimes between messages sent to distant stars and messages sent back.

furyofantares 1y ago
Wouldn't you want to completely saturate your bandwidth? Just always be transmitting whatever message has been transmitted the least.
- knome 1y ago
  that would probably depend on how much power it takes to send the messages, how much actual usable bandwidth you could manage over the distances involved, and how much data you want to send. if it takes a large amount of energy to send the data, we probably wouldn't want to run the equipment all the time. strong pulses would let the equipment cool down or recharge capacitor banks or whatever during downtime. interstellar dust and other debris floating through space could cause interference, not to mention radiation from everything else around us, and our own sun shining right next to our little laser. might want to move the laser out onto pluto or something to avoid having it right up against the sun.
scottyah 1y ago
and you'd probably want to take orbits/vectors into account, a djikstra-esque algorithm where the distances change is crazy. Also, our signals are usually going very short distances very quickly and are very protected from solar/cosmic waves by the ionosphere. What kind of data loss could you get transmitting in open space across vast distances and time?

jvanderbot 1y ago

I agree! This was my obsession when I worked at JPL, unfortunately the answer was usually "no mission will sacrifice their budget for reusable assets". You'd need a mission whose purpose is to emplace compute stations. That's why we can't have nice things.

r14c 1y ago

you'd probably want a different protocol than IPFS for that application. managing a DHT with extremely high latency isn't going to work very well. something like named-data networking would probably work better since the transmitter can know 1. exactly what prefixes need to be buffered based on the received interest messages from deep space 2. exactly which data rate is possible at any given time 3. exactly how much data needs to be sent from the buffer in each transmission optimizing for high latency really pushes your design choices around compared to our comparatively very low latency uses here on earth. its pretty interesting to think about.

unit149 1y ago

[dead]