Why Thermodynamics Rules Future Orbital Data Centers

(spectrum.ieee.org)

38 points | by rbanffy 2 hours ago

15 comments

  • tristanj 1 hour ago
    Economics calculator for Orbital vs Terrestrial Data Centers

    https://andrewmccalip.com/space-datacenters

    You can play around with the cost sliders to estimate the economics, but even being quite optimistic, space data centers cost ~2-3x of their terrestrial counterparts.

    • PowerfulWizard 14 minutes ago
      To remove heat by radiation there's a big benefit to running the GPUs hotter as the radiation will be proportional to the fourth power of temperature. This resource is using 85 deg C versus 60 deg C for OP which will improve cooling performance.

      If Nvidia/SpaceX can make the chips run at a higher temperature that would help a lot although I assume it would have already been done if it were possible. Another option is to add a heat pump to raise radiator temperature if the smaller radiator mass can pay for the heat pump mass.

    • krunck 9 minutes ago
      They'll pay the price if it means their data centers are immune to the anger of the commoners who are being surveilled, analyzed, and manipulated by systems running on these data centers.
    • biomcgary 35 minutes ago
      But, datacenter development in space does not deal with local NIMBYs, just centralized decision-makers that are easier to "influence".
      • nba456_ 19 minutes ago
        The NIMBYs are coming for space launch sites, too.
        • arjie 10 minutes ago
          That particular concern is currently covered as far as SpaceX is concerned since it launches under DoD coverage. See the California Coastal Commission and the fact that they had to apologize etc. for attempted overreach.
    • OutOfHere 33 minutes ago
      You are altogether externalizing the cost of carbon dioxide emissions that humanity has to pay for. The resulting global warming is not a joke. The heat problem cumulatively is bigger on Earth than it would be in space.
      • xnx 21 minutes ago
        Cost = emmissions
  • Zigurd 38 minutes ago
    Remember space manufacturing? When the first modules of ISS were launched 27 years ago, that was supposed to be the next big thing. Space manufacturing, asteroid mining, and space data centers are pipedreams. The capital equipment is too heavy, and 100% forever automated operations are not realistic.
    • 6510 19 minutes ago
      It's still full of delicious rocks with completely insane market value. They sit there waiting for our greed and capabilities to reach escape velocity. Some day there will be a TEMU space station drop shipping custom fidget spinners to wherever we desire them. Probably not any time soon but eventually...
  • melodyogonna 7 minutes ago
    All very interesting, but I'd wait and see what people with real-world experience running Spacecraft can come up with before dismissing the entire endeavor.
  • arjie 1 hour ago
    Only a single order of magnitude of cost? So a $4b data center on Earth delivers the same value as a $40b data center in Space? So if you have greater than a 95% operating margin and capacity constraints (either due to nation environmental law, power limits, or other such blockers) then this is a no-brainer - a 95% operating margin becomes a 50% operating margin. The return on capital is much much lower so you have to be anticipating cheaper capital, even cheaper costs than this in practice, or something else.

    Inference margins are some 70% right now? So it needs quite some work on both sides but this seems to make it seem more achievable than I previously thought.

    • giraffe_lady 58 minutes ago
      It assumes $44/kg to launch into orbit. Idk where that came from if it's a musk claim or what but it's ludicrous against current costs. Currently still at thousands/kg and dropping but nowhere near $44 and I haven't heard anyone claim that's likely who isn't selling a rocket company.
      • PowerfulWizard 2 minutes ago
        Musk is deliberately creating a business that needs high volume low cost launch services because in order to get low cost launch high volume is needed, and in order to get high volume a customer is needed. In the same way that Starlink launches were used to create the Falcon 9 economies of scale, the orbital AI will be used to create the Starship economies of scale. He also wants to bet the whole company on this which creates pressure to deliver and not just coast on what they've already accomplished. There are a bunch of related high risk bets but they ultimately connect back to bringing Mars within reach with frequent low cost launch capability.
      • mikestorrent 13 minutes ago
        That seems pretty cheap, like, can I launch my cat's ashes into space or something for $50?
      • bluecalm 21 minutes ago
        The plan is to launch from Earth in the beginning stages and then switch to launching from the Moon which has no atmosphere so you don't need rockets and can use an electromagnetic gun instead. That requires satellite manufacturing on the Moon and I guess the minerals required will come from asteroid mining.

        That's my understanding of what Elon said about how it's going to work.

        • davidkwast 12 minutes ago
          So the majority of the hardware should stay on the moon where latency isn't so critical. There the cooling won't be the problem.
    • stackghost 53 minutes ago
      >So a $4b data center on Earth delivers the same value as a $40b data center in Space?

      It may do so, initially, compared to a new-build DC.

      But, critically, you can upgrade the racks in an already-built DC without demolishing the entire building. You can't do that in orbit, so the full lifecycle ROI is lower.

      Orbital DCs are constrained by cooling and by bandwidth. Even a space-to-ground laser (which does not currently exist in a sufficiently-mature form) has a fraction of the bandwidth of a proper terrestrial fiber line. So you're paying at least 10x for essentially a disposable datacenter that can't move as much data in or out, and likely will not be as powerful as a terrestrial DC because of the cooling constraint, just to have it in space because reasons.

      I don't see the business case, at all.

      This is so transparently another hyperloop-esque pipe dream invented for the sole purpose of inflating SpaceX's valuation.

  • inopinatus 29 minutes ago
    “Solved problem”. https://en.wikipedia.org/wiki/Matrioshka_brain

    It merely remains to build one.

    • mikestorrent 14 minutes ago
      Silly human, won't be us building that. Just hope that you get one of the nice gilded cages!
  • jobead 1 hour ago
    Why is everyone so focused on heat when cosmic rays randomly scrambling memory is going to be a much bigger problem?
    • jcranmer 30 minutes ago
      When I was peripherally working on some HPC stuff, there was a comment by one of the hardware guys that it mattered which national lab you were building the supercomputer for, because the guys at high altitude like Los Alamos get a lot more bitflips than someone closer to sea-level like Argonne. Although that said, for an exascale supercomputer, the mean time between uncorrected bit flip somewhere in the machine is on the order of a few hours, which means that large supercomputer-scale workloads should actually expect to hit a bit flip in their computation.
    • Pxtl 59 minutes ago
      Cosmic rays can probably be resolved with some parity bits and redundancy. Especially since these don't have to be located way up in geosynch, lower orbits get you more magnetosphere protection.

      Not that it isn't a problem, but I think heat dissipation will have the edge.

      • rbanffy 57 minutes ago
        You can also place the most sensitive electronics inside a module within the propellant tank. That also should help a lot.
      • convolvatron 15 minutes ago
        I worked at the architecture level on designs to mitigate signal corruption inside the asic. I don't remember the exact numbers, and obviously it depends on the design. but you need to add error detection and correction on every path (busses, mixes, registers, function units, etc). the number I seem to recall was a 25% area overhead and a nominal decrease in clock rate. this was for an earth-bound very large machine, so idk if that would be sufficient for space. usually those designs have much larger nodes and much slower clock rates. primarily because of damage caused by ionizing radiation that accumulates over time.

        so sure, the heat issue seems fatal, but rad-hard designs will certainly have a bottom line impact

    • cmrdporcupine 53 minutes ago
      I mean, LLMs are already a pile of stochastic output .. maybe that just adds to the fun? /s
      • mikestorrent 12 minutes ago
        Finally, the classic BOFH excuse of sunspots causing issues will be true
  • ge96 1 hour ago
    I'm excited I think of the Cowboy Bebop episode (Jamming With Edward) where they hunt down a rogue satellite to get data off it.

    Also think it would be crazy to have a worm spread across the servers/starlink, would there be an antivirus system onboard or maybe not applicable, says RTOS can get a virus

  • khuey 46 minutes ago
    I'm not usually an "AI is going to kill us all" kind of person but on the off chance we do get Skynet/etc why would we give the machines the literal high ground?
    • short_sells_poo 24 minutes ago
      Because that's the next generation's problem, and we can do more to mortgage their future for our own luxury :)
  • poppafuze 24 minutes ago
    Gravity. That's what rules orbital-anything.
  • CuriouslyC 1 hour ago
    Honestly, data centers in the ocean make so much more sense than data centers in space it's kind of silly, but Mr Moneybags owns a rocket company he's trying to pump and dump, not a submarine company, so here we are.
    • rtkwe 56 minutes ago
      It's like the idea of Mars as a backup to human civilization. The technology required to make Mars livable and independent from Earth is so advanced it would allow you to survive basically anything here on Earth already.
    • rbanffy 54 minutes ago
      I would suggest data centres near the arctic - it's close to most of the Northern hemisphere's users, presents an easy option for cooling (the place is a heat sink), and, with collapsing glaciers, there will be abundant hydro power to be used.

      It has the killer feature of allowing a human to walk up to a rack and replace a component.

      • CuriouslyC 50 minutes ago
        One huge advantage of ocean data centers is that you can do geothermal down there more cheaply and easily, and it's a very consistent source of power, so you don't even need hydro. Additionally, deep ocean water is consistently very near freezing, you could get below freezing out of the water but then you lose conduction efficiency.

        The replacability is nice, but even in terrestrial data centers there are situations where something fails and it never gets replaced, just routed around, until the pod gets ripped out and replaced in its entirety.

      • stackghost 49 minutes ago
        >I would suggest data centres near the arctic - it's close to most of the Northern hemisphere's users, presents an easy option for cooling (the place is a heat sink), and, with collapsing glaciers, there will be abundant hydro power to be used.

        Advocating for exacerbating the melting of the polar ice cap, which will endanger dozens of millions of people, just to have more convenient data centers for manufacturing AI slop, is peak HN.

    • hangonhn 1 hour ago
      I know Microsoft tried it. They had a press release saying it was successful but never did it again. Does anyone know more about that? I agree with you that data centers in the ocean seem a better bet.
    • arjie 46 minutes ago
      What’s the regulatory path to something like this? Oceans seem to have all the problems of land except manifold: permitting is nigh impossible, and power is hard to line up.

      To make it worse, underwater tech is notoriously hard to make operationally visible. Sabotage is trivial and undifferentiable from failure and honest error. When we used to work in trading subsea cable cuts in Asia would constantly ruin our best networks. Everyone had point to point microwave expressly because it wasn’t breakable in this way. Exposing compute to this rather than just networking would have doomed the entire enterprise.

    • Zigurd 45 minutes ago
      He must have that cave submarine lying around somewhere.
    • cmrdporcupine 52 minutes ago
      Corrosion is one hell of a problem in salt water.

      I think the specific attraction to space is the copious massive amounts of free solar energy, isn't it?

      (In reality, they want to build the torment nexus at the Lagrange points because that would just be edgy-as-fuck)

      • jubilanti 31 minutes ago
        > I think the specific attraction to space is the copious massive amounts of free solar energy, isn't it?

        Yes you get more energy harvest from solar above the atmosphere and can orient them to always be pointed towards the sun. But it is still so much more expensive than building out conventional solar in the Sun Belt, which is so much more expensive than just building a massive natural gas plant right next to people's homes.

        No, space is desirable because there is no local permitting authority that can push back. People living near data centers have gotten wise to the fact that local people pay most of the externalities of data centers and AI, but the benefits mostly go elsewhere, and the jobs created during construction are temporary. In space, you don't have to lobby/bribe local politicians and astroturf a YIMBY movement.

        • wahern 16 minutes ago
          > People living near data centers have gotten wise to the fact that local people pay most of the externalities of data centers and AI, but the benefits mostly go elsewhere.

          That's true of just about every industrial, commercial, civic, or residential site. It's the fundamental premise behind every NIMBY protest ever. The benefit of each individual site always runs disproportionately to people further away. It's only in the aggregate, i.e. each individual enjoying the cumulative externalized benefits from far-off, that the equation could ever balance.

      • CuriouslyC 41 minutes ago
        That is a problem, but you already have to contend with GPU refresh every ~6 years, it's likely you'd pre-build pods that you could sink and link, then you'd float them and refurbish at refresh time. With that cycle time it's a manageable engineering challenge.
  • ForHackernews 1 hour ago
    Tyranny of the rocket equation[0] makes it hard for me to conceive how an orbital data centre could ever make sense.

    If you just want to escape permitting laws, why not float it in international waters? That's a much more accessible and hospitable environment than LEO.

    [0] https://archive.is/qp4gP

    • ggreer 30 minutes ago
      Space gets you 24/7 solar power. To run a data center for 12 hours without sunlight, you'd need massive batteries. Also oceans have weather and corrosion.

      The issue with putting stuff in space isn't the kinetic energy required. In LEO that's about 30 megajoules per kilogram or $5 worth of propellant. The issue is that orbital launch vehicles are not reusable, so you must destroy an expensive rocket to get your payload to orbit. All of these space datacenter efforts are betting that Starship will be fully reusable.

  • 2OEH8eoCRo0 1 hour ago
    > At ABI Research, where I work as an aerospace analyst, we did a rough total-cost-of-ownership comparison between a data center on Earth and one in space. It showed that the cost to launch and run a GPU in space for a year is at least an order of magnitude higher than the same feat in a terrestrial data center.
    • mannykannot 57 minutes ago
      And in the next paragraph:

      "However, there are niche applications where the much higher costs of computing in space could be justified. Examples include ... active collision avoidance in the increasingly crowded low Earth orbit."

      A self-justifying purpose!

    • btilly 1 hour ago
      Just so that nobody jumps in with what I first wanted to jump in with, this estimate was done with the assumption that Elon Musk's Starship is built, works as advertised, and launch costs are at the lower end of the projected range.

      It wasn't an order of magnitude more because of how expensive rocket launches currently are.

      (I'm glad that I read the article before arguing this one...)

  • OutOfHere 28 minutes ago
    The best thing for space GPUs would to run at a much high temperature, thereby allowing the radiator to be fairly small. This would require a special high-temperature GPU, with robust radiation protection and error correction, ideally in solar orbit. I have a video https://youtu.be/s7Mv_OcBXI8 covering the approach for heat rejection.
  • macspoofing 19 minutes ago
    >Why Orbital Data Centers Are Harder Than Silicon Valley Thinks

    Who thinks they are easy? Elon Musk? The guy that spews obvious (even to him) bullshit like we're going to Mars in the next 5 years?

    I don't even want to read the article. It is obvious that Orbital Data Centers have MASSIVE engineering challenges. They may never be cost-effective.

  • josefritzishere 1 hour ago
    I appreciate the sci-fi quality of this but when the IPO comes remember the "fi" stands for "fiction."