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How do you cool a data center in a vacuum?

by vrganj 2mo ago

GMoromisato 2mo ago
How is Starlink cooled? How is ISS cooled? They all use radiators, which work in a vacuum by--wait for it--radiating infrared into space. Orbital data centers do not defy the laws of physics. TBD whether they are economical relative to terrestrial data centers, but please don't succumb to misinformation.
- dgellow 2mo ago
  They do and you’re the one spreading misinformation… the amount of energy you need to radiate for inference GPUs is enormous compared to any computer currently used in space. Energy dissipation by radiating is literally the least effective method and would require insanely large radiators just to be effective on paper. You also need to mitigate bit flips, meaning you throw away around 2/3 of your compute capacity. And that’s just the most basic things, before taking in account ALL the other problems you face doing compute in space someone with expertise in the domain could mention. Datacenters in space is a grift that won’t happen in any meaningful capacity and can be debunked by a 15y old who followed their physics courses
  - GMoromisato 2mo ago
    You've listed: 1. Radiating heat needs large radiators 2. Bit flips require extra compute capacity Neither of those violate the laws of physics. As I said, they may not work economically, but that depends on a large number of unknowns, including the cost per ton to orbit and the cost per GW of new power capacity on Earth in 2030. If you have a time machine and know those numbers, then can I please borrow your time machine? Moreover, when you say, "ALL the other problems ... someone with expertise in the domain could mention," you're saying either: A) SpaceX engineers do not have expertise in this domain. B) SpaceX engineers are hiding all the problems that they know about. B is basically a conspiracy theory. It is one YouTube video away from saying the moon landing was a hoax. A is just delusional.
    - vrganj 2mo ago
      So between the giant radiator per GPU and the diminished compute capacity, how much mass are we shooting up exactly? This just seems utterly infeasible. You're missing C) SpaceX engineers know it's a bad idea, but can't say anything because it's the tyrant manchild's latest obsession, technology constraints be damned. Remember the vision-only FSD? How's that coming along?
      - ethbr1 2mo ago
        > because it's the tyrant manchild's latest obsession, technology constraints be damned. Imho, there's only one reason that justifies Musk's space-based compute obsession: sovereignty. Specifically, avoiding terrestrial country's. This isn't about AI in space (though I'm sure dumb investors love that), it's about uncensorable Twitter in space, beamed down to Starlink terminals. Which would be one of the few things you'd care about, if you were one of the richest people on the planet... but still subject to those damned nations and their meddling laws.
        jacquesm 2mo ago
        That's exactly it. Musk sees space as extraterritorial, which in the true sense of the word of course it absolutely is. But all those bits have to go to ground somewhere. As long as that somewhere is friendly no problem. That can change.
        solid_fuel 2mo ago
        Yeah, I think Musk loves the idea of sticking his CSAM generators in space, where he thinks they will be beyond the reach of terrestrial laws and morals.
        grim_io 2mo ago
        If Elon wants to offer space-twitter, he still needs to abide by the rules of the country he is offering the service to. Unless he's offering it to the aliens orbiting his magical lawless space data centers.
- vel0city 2mo ago
  For some perspective, the entire heat rejection system on the ISS at peak can do a little less than one rack of dense AI compute power. All of that plumbing, all of that area, all that stuff to put in orbit just to cool one rack of compute equipment. How much stuff do we need to put up there for each rack? The External Active Thermal Control System on the ISS is ~20,000lbs, about 10 tons. How many racks are in a single datacenter? The Colossus is allegedly ~1,500 compute racks, ignoring other equipment. So that's like 15,000 tons for just the cooling equipment if its like the ISS. At SpaceX's current public launch costs (which makes a profit for them, so not base costs) to launch that much stuff is somewhere around $40B. Just the launch cost for the cooling equipment alone for just one datacenter building worth of pure compute capacity, that isn't even that big compared to what companies are talking about building. All of that is very rough back of the napkin math. I don't expect that to be the actual numbers at all, but I'd imagine somewhere in that neighborhood unless they've got something really radical up their sleeve. They better have a much better way to cool these things than what the ISS is doing.
  - GMoromisato 2mo ago
    Current SpaceX design is 75 kW of computer per ton, including solar panels, radiators, everything: https://www.spacex.com/spacexai/starmind https://www.spacex.com/spacexai/starmind That's ~13 tons per megawatt, or 1,330 tons for 100 MWs. That's 13 launches of Starship (at $10 million per launch, or $130 million). Of course, that's probably 600 individual satellites, at maybe $5 million per, so we're at ~$3 billion to deploy 100 MW to space. You can sell 100 MW of compute for $3-4 billion per year, so SpaceX would make their money back in 1 year.
    - vel0city 2mo ago
      > Current SpaceX design is 75 kW of computer per ton, including solar panels, radiators, everything Anyone can make a website. Let's see them actually make it and put it in orbit. According to another Musk website we'd be riding hyperloops and drive through solo tunnels under our cities and we'd all own our own autonomous cab companies back in 2016. Another website said we'd be able to buy a Cybertruck for $40k and the three-motor variety for $70k.

How do you cool a data center in a vacuum?

by vrganj 2mo ago

How do you cool a data center in a vacuum?

How is Starlink cooled? How is ISS cooled? They all use radiators, which work in a vacuum by--wait for it--radiating infrared into space. Orbital data centers do not defy the laws of physics. TBD whether they are economical relative to terrestrial data centers, but please don't succumb to misinformation.

dgellow 2mo ago
They do and you’re the one spreading misinformation… the amount of energy you need to radiate for inference GPUs is enormous compared to any computer currently used in space. Energy dissipation by radiating is literally the least effective method and would require insanely large radiators just to be effective on paper. You also need to mitigate bit flips, meaning you throw away around 2/3 of your compute capacity. And that’s just the most basic things, before taking in account ALL the other problems you face doing compute in space someone with expertise in the domain could mention. Datacenters in space is a grift that won’t happen in any meaningful capacity and can be debunked by a 15y old who followed their physics courses
- GMoromisato 2mo ago
  You've listed: 1. Radiating heat needs large radiators 2. Bit flips require extra compute capacity Neither of those violate the laws of physics. As I said, they may not work economically, but that depends on a large number of unknowns, including the cost per ton to orbit and the cost per GW of new power capacity on Earth in 2030. If you have a time machine and know those numbers, then can I please borrow your time machine? Moreover, when you say, "ALL the other problems ... someone with expertise in the domain could mention," you're saying either: A) SpaceX engineers do not have expertise in this domain. B) SpaceX engineers are hiding all the problems that they know about. B is basically a conspiracy theory. It is one YouTube video away from saying the moon landing was a hoax. A is just delusional.
  - vrganj 2mo ago
    So between the giant radiator per GPU and the diminished compute capacity, how much mass are we shooting up exactly? This just seems utterly infeasible. You're missing C) SpaceX engineers know it's a bad idea, but can't say anything because it's the tyrant manchild's latest obsession, technology constraints be damned. Remember the vision-only FSD? How's that coming along?
    - ethbr1 2mo ago
      > because it's the tyrant manchild's latest obsession, technology constraints be damned. Imho, there's only one reason that justifies Musk's space-based compute obsession: sovereignty. Specifically, avoiding terrestrial country's. This isn't about AI in space (though I'm sure dumb investors love that), it's about uncensorable Twitter in space, beamed down to Starlink terminals. Which would be one of the few things you'd care about, if you were one of the richest people on the planet... but still subject to those damned nations and their meddling laws.
      - jacquesm 2mo ago
        That's exactly it. Musk sees space as extraterritorial, which in the true sense of the word of course it absolutely is. But all those bits have to go to ground somewhere. As long as that somewhere is friendly no problem. That can change.
      - solid_fuel 2mo ago
        Yeah, I think Musk loves the idea of sticking his CSAM generators in space, where he thinks they will be beyond the reach of terrestrial laws and morals.
      - grim_io 2mo ago
        If Elon wants to offer space-twitter, he still needs to abide by the rules of the country he is offering the service to. Unless he's offering it to the aliens orbiting his magical lawless space data centers.
vel0city 2mo ago
For some perspective, the entire heat rejection system on the ISS at peak can do a little less than one rack of dense AI compute power. All of that plumbing, all of that area, all that stuff to put in orbit just to cool one rack of compute equipment. How much stuff do we need to put up there for each rack? The External Active Thermal Control System on the ISS is ~20,000lbs, about 10 tons. How many racks are in a single datacenter? The Colossus is allegedly ~1,500 compute racks, ignoring other equipment. So that's like 15,000 tons for just the cooling equipment if its like the ISS. At SpaceX's current public launch costs (which makes a profit for them, so not base costs) to launch that much stuff is somewhere around $40B. Just the launch cost for the cooling equipment alone for just one datacenter building worth of pure compute capacity, that isn't even that big compared to what companies are talking about building. All of that is very rough back of the napkin math. I don't expect that to be the actual numbers at all, but I'd imagine somewhere in that neighborhood unless they've got something really radical up their sleeve. They better have a much better way to cool these things than what the ISS is doing.
- GMoromisato 2mo ago
  Current SpaceX design is 75 kW of computer per ton, including solar panels, radiators, everything: https://www.spacex.com/spacexai/starmind https://www.spacex.com/spacexai/starmind That's ~13 tons per megawatt, or 1,330 tons for 100 MWs. That's 13 launches of Starship (at $10 million per launch, or $130 million). Of course, that's probably 600 individual satellites, at maybe $5 million per, so we're at ~$3 billion to deploy 100 MW to space. You can sell 100 MW of compute for $3-4 billion per year, so SpaceX would make their money back in 1 year.
  - vel0city 2mo ago
    > Current SpaceX design is 75 kW of computer per ton, including solar panels, radiators, everything Anyone can make a website. Let's see them actually make it and put it in orbit. According to another Musk website we'd be riding hyperloops and drive through solo tunnels under our cities and we'd all own our own autonomous cab companies back in 2016. Another website said we'd be able to buy a Cybertruck for $40k and the three-motor variety for $70k.