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Mein Gott, you're not just making this up ( https://www.datacenterdynamics.com/en/news/neevcloud-and-agnikul-cosmos-plan-to-launch-data-centers-in-space/ https:

Mein Gott, you're not just making this up ( https://www.datacenterdynamics.com/en/news/neevcloud-and-agnikul-cosmos-plan-to-launch-data-centers-in-space/ https://www.datacenterdynamics.com/en/news/neevcloud-and-agn... ). But.. why? Musk bandwagon-hopping? Investor bamboozlery? (Same diff?) Is my borderline childish understanding of basic physics THAT off because I cannot see the value or utility (beyond a small smear of niche edge cases) of space-based compute? - ed, disclosure: You seem to have edited your response whilst I was typing mine, adding in valuable links. Thanks!

TeMPOraL 2mo ago
> Is my borderline childish understanding of basic physics THAT off because I cannot see the value or utility (beyond a small smear of niche edge cases) of space-based compute? Don't worry, most of the people online didn't get the memo on this. One of the major selling points of orbital compute is power supply - more specifically, it turns out that, compared to beaming power from space, it's projected to be cheaper to move compute upwell instead - atmosphere losses for beamed power are just too big. Of course this doesn't matter if you can get cheap, clean power from elsewhere (e.g. nuclear). This is in general data center case. Here, GP says the motivation is reducing C2 RTT, which makes sense for military applications.
- rayiner 2mo ago
  Could we have giant nuclear reactors in space? What's the power loss from beaming down power?
  - TeMPOraL 2mo ago
    > Could we have giant nuclear reactors in space? We could. The usual stumbling block is how to ship fissile material upwell without the risk of a launch failure spreading highly radioactive material over several countries. > What's the power loss from beaming down power? I think it's about 10% from atmosphere alone, but you have to add losses from other components in the system, including light -> current -> RF and RF -> current legs, and I've seen estimates ranging from 15% to 40% efficiency end to end; this random article includes breakdown with estimates, that multiplies down to 37.5% efficiency end-to-end. https://www.sciencedirect.com/topics/earth-and-planetary-sciences/power-beaming https://www.sciencedirect.com/topics/earth-and-planetary-sci... EDIT: This system design gives 7-14% end-to-end efficiency: https://arxiv.org/pdf/2206.08373 https://arxiv.org/pdf/2206.08373 EDIT2: Also to spell out another non-obvious aspect of beamed power, it turns out that it's not the efficiency that's the limiting factor per se, but land - you can improve efficiency by building larger rectennas, but it gets very expensive very quickly once you consider paying for land under them.
  - OneDonOne 2mo ago
    See: SNAP-10A BES-5 (oops, sorry 'bout that Canada!) TOPAZ-I Kiwi, Phoebus, and NRX (Mars here we come!) RD-0410 (Dossvidanya Solar System!) SP-100 TOPAZ-II Kilopower
  - pantalaimon 2mo ago
    We already have a giant fusion reactor in space
    - TeMPOraL 2mo ago
      Yes, and "beamed power" is exactly about tapping into it some more downwell. As outlined in other comments, it's not currently the best option.
- detritus 2mo ago
  My concern is more in the realms of cooling. I know there's the potential for lots of 'free' energy up there, but how do you then ensure your space-based array of GPU farms bleed all of the resultant heat?
  - alephnerd 2mo ago
    From a Defense perspective, it's acceptable if multiple ODC fails and you have to re-launch another one. This is why these are being treated as part of a mesh. These aren't supposed to be a commercial DC and are intended to be a mesh of multiple racks in orbit. The fact that the US, China, Russia, and India have already deployed ASATs means a Kessler effect if a question of when and not if.
    - laughing_man 2mo ago
      The Russians put the first ASats up in the '70s. Their existence doesn't require use.
      - alephnerd 2mo ago
        The difference is India and China had an orbital near-miss in 2024 [0] and both India and China now field ASATs. It's a matter of time before Japan, SK, Iran, Israel, UAE, KSA, etc build similar capabilities. [0] - https://www.bloomberg.com/news/articles/2025-09-22/india-plans-bodyguard-satellites-after-risky-orbital-near-miss https://www.bloomberg.com/news/articles/2025-09-22/india-pla...
  - TeMPOraL 2mo ago
    This is like "how do you ensure you can bring back home all the groceries you bought" kind of problem. Space 101. We know how much heat we can bleed off, how, and how fast, and this gives us bounds on how much power we can use, and that is the starting point - you design everything around that.
- notahacker 2mo ago
  The unit economic tradeoffs aren't quite that straightforward (beamed power is lossy enough to require more panels[1], but solar cells and satellite structures have longer useful lives than inference chips so over longer time periods you likely end up launching more stuff into space with disposable datacentres anyway[2], particularly given the datacentres also need bigger radiators. Other issues which favour power being beamed to the ground are not exposing those expensive chips to radiation, and being able to replace them on cycles dictated by inference chip innovation or end-of-life rather than fixed cycles depending on a satellite propellant budget... The other comparison point is of course plain old terrestrial power sources, including energy storage in the mix if it relies heavily on solar power without a sufficiently global grid. Not having to launch into space buys a lot of power. C2 RTT times and edge computation of large datasets collected in space make much more sense since unit economics aren't the driving factor, but are unlikely to need datacentres on the same scale as inference compute for the general population (another reason why this use case makes more sense) [1]but I think the underrated problem with beamed power isn't just the low maturity of the technology, but that as soon as you start talking about sending power to earth via RF or laser you're going to encounter political opposition that makes objections to terrestrial datacentres seem tame.... [2]chips can in theory be replaced on orbit, but the "million satellite" filings are disposable. Replenishing propellant for a few large power stations, potentially on longer cycles, is a simpler task.
  - TeMPOraL 2mo ago
    > beamed power is lossy enough to require more panels[1] What kills that is simply costs of land. You have to put these larger rectennas somewhere, and land ain't getting cheaper.
    - notahacker 2mo ago
      Non-exclusive use of farmland or wasteland (or even - at least until maintenance complexity is considered - offshore) isn't a major barrier; we have many many miles of wires and pylons crossing farmland for regular terrestrial grids already. A rectenna looks more like a mesh than a set of panels: the idea is that the visible light spectrum passes through and the target microwave frequencies don't, so unlike a photovoltaic solar farm the land underneath is fine for farming. Nominally the land is safe to be occupied or passed through by humans too, although they might take some convincing. It becomes a problem when people start trying to get the rectennae banned...
- Dylan16807 2mo ago
  > it turns out that, compared to beaming power from space, it's projected to be cheaper to move compute upwell instead This is damning with the faintest of praise. Beaming power from space is a terrible idea.
- laughing_man 2mo ago
  Everybody keeps talking about cheap, clean power. But where I live the price of power has gone up dramatically in recent years. Free power (well, marginally free, anyway) is a major plus.
  - wazoox 2mo ago
    In France, where we have relatively cheap and clean energy, they plan to build GW DCs with GWs setups of diesel backup generators. When these will run, the pollution will be staggering.
rayiner 2mo ago
> Is my borderline childish understanding of basic physics THAT off because I cannot see the value or utility (beyond a small smear of niche edge cases) of space-based compute? In the real world, "physics" is not necessarily the gating factor. There is a major concern about the environmental footprint of terrestrial data centers, to the point where major U.S. states are enacting moratoriums: https://www.governor.ny.gov/news/first-statewide-moratorium-new-hyperscale-data-centers-launched-governor-kathy-hochul https://www.governor.ny.gov/news/first-statewide-moratorium-.... These legal and social roadblocks must be accounted for in analyzing the viability of orbital data centers.
- OneDonOne 2mo ago
  If the "physics" tells you that your satellite cannot radiate heat away from your nVidia GPU cluster because each H100 needs 1.1 meter square of radiator, then opinions do not matter. The same applies to power supply and bandwidth.
  - pfdietz 2mo ago
    What are the assumptions behind that 1.1 m^2 figure?
    - alephnerd 2mo ago
      OP is quoting Mikhail Klassen at Planet Labs [0]. The cost of replacement is exorbitant for commercial usecases, but is acceptable for defense usecases. The issue is too many people are looking at the commercial usecase while ignoring the defense usecase that is what is actually driving the conversation and dealflow in this segment. [0] - https://www.mikhailklassen.com/posts/orbital-data-centers/orbital-data-centers/ https://www.mikhailklassen.com/posts/orbital-data-centers/or...
      - pfdietz 2mo ago
        Ok, there are at least two bad assumptions there. First, it assumes the radiator is at the same temperature as the GPU. But radiators become dramatically more effective as temperature increases, with radiated power increasing as the fourth power of absolute temperature. So a heat pump that drives the radiator at higher temperature could make the radiator far smaller. More power would be required (and the radiator would have to radiate this energy too) but the radiator could become much smaller. The other problem is assuming the radiator is intercepting sunlight. But it can be shaded by reflective films or kept edge-on to the Sun.

TeMPOraL 2mo ago

> Is my borderline childish understanding of basic physics THAT off because I cannot see the value or utility (beyond a small smear of niche edge cases) of space-based compute? Don't worry, most of the people online didn't get the memo on this. One of the major selling points of orbital compute is power supply - more specifically, it turns out that, compared to beaming power from space, it's projected to be cheaper to move compute upwell instead - atmosphere losses for beamed power are just too big. Of course this doesn't matter if you can get cheap, clean power from elsewhere (e.g. nuclear). This is in general data center case. Here, GP says the motivation is reducing C2 RTT, which makes sense for military applications.

rayiner 2mo ago
Could we have giant nuclear reactors in space? What's the power loss from beaming down power?
- TeMPOraL 2mo ago
  > Could we have giant nuclear reactors in space? We could. The usual stumbling block is how to ship fissile material upwell without the risk of a launch failure spreading highly radioactive material over several countries. > What's the power loss from beaming down power? I think it's about 10% from atmosphere alone, but you have to add losses from other components in the system, including light -> current -> RF and RF -> current legs, and I've seen estimates ranging from 15% to 40% efficiency end to end; this random article includes breakdown with estimates, that multiplies down to 37.5% efficiency end-to-end. https://www.sciencedirect.com/topics/earth-and-planetary-sciences/power-beaming https://www.sciencedirect.com/topics/earth-and-planetary-sci... EDIT: This system design gives 7-14% end-to-end efficiency: https://arxiv.org/pdf/2206.08373 https://arxiv.org/pdf/2206.08373 EDIT2: Also to spell out another non-obvious aspect of beamed power, it turns out that it's not the efficiency that's the limiting factor per se, but land - you can improve efficiency by building larger rectennas, but it gets very expensive very quickly once you consider paying for land under them.
- OneDonOne 2mo ago
  See: SNAP-10A BES-5 (oops, sorry 'bout that Canada!) TOPAZ-I Kiwi, Phoebus, and NRX (Mars here we come!) RD-0410 (Dossvidanya Solar System!) SP-100 TOPAZ-II Kilopower
- pantalaimon 2mo ago
  We already have a giant fusion reactor in space
  - TeMPOraL 2mo ago
    Yes, and "beamed power" is exactly about tapping into it some more downwell. As outlined in other comments, it's not currently the best option.
detritus 2mo ago
My concern is more in the realms of cooling. I know there's the potential for lots of 'free' energy up there, but how do you then ensure your space-based array of GPU farms bleed all of the resultant heat?
- alephnerd 2mo ago
  From a Defense perspective, it's acceptable if multiple ODC fails and you have to re-launch another one. This is why these are being treated as part of a mesh. These aren't supposed to be a commercial DC and are intended to be a mesh of multiple racks in orbit. The fact that the US, China, Russia, and India have already deployed ASATs means a Kessler effect if a question of when and not if.
  - laughing_man 2mo ago
    The Russians put the first ASats up in the '70s. Their existence doesn't require use.
    - alephnerd 2mo ago
      The difference is India and China had an orbital near-miss in 2024 [0] and both India and China now field ASATs. It's a matter of time before Japan, SK, Iran, Israel, UAE, KSA, etc build similar capabilities. [0] - https://www.bloomberg.com/news/articles/2025-09-22/india-plans-bodyguard-satellites-after-risky-orbital-near-miss https://www.bloomberg.com/news/articles/2025-09-22/india-pla...
- TeMPOraL 2mo ago
  This is like "how do you ensure you can bring back home all the groceries you bought" kind of problem. Space 101. We know how much heat we can bleed off, how, and how fast, and this gives us bounds on how much power we can use, and that is the starting point - you design everything around that.
notahacker 2mo ago
The unit economic tradeoffs aren't quite that straightforward (beamed power is lossy enough to require more panels[1], but solar cells and satellite structures have longer useful lives than inference chips so over longer time periods you likely end up launching more stuff into space with disposable datacentres anyway[2], particularly given the datacentres also need bigger radiators. Other issues which favour power being beamed to the ground are not exposing those expensive chips to radiation, and being able to replace them on cycles dictated by inference chip innovation or end-of-life rather than fixed cycles depending on a satellite propellant budget... The other comparison point is of course plain old terrestrial power sources, including energy storage in the mix if it relies heavily on solar power without a sufficiently global grid. Not having to launch into space buys a lot of power. C2 RTT times and edge computation of large datasets collected in space make much more sense since unit economics aren't the driving factor, but are unlikely to need datacentres on the same scale as inference compute for the general population (another reason why this use case makes more sense) [1]but I think the underrated problem with beamed power isn't just the low maturity of the technology, but that as soon as you start talking about sending power to earth via RF or laser you're going to encounter political opposition that makes objections to terrestrial datacentres seem tame.... [2]chips can in theory be replaced on orbit, but the "million satellite" filings are disposable. Replenishing propellant for a few large power stations, potentially on longer cycles, is a simpler task.
- TeMPOraL 2mo ago
  > beamed power is lossy enough to require more panels[1] What kills that is simply costs of land. You have to put these larger rectennas somewhere, and land ain't getting cheaper.
  - notahacker 2mo ago
    Non-exclusive use of farmland or wasteland (or even - at least until maintenance complexity is considered - offshore) isn't a major barrier; we have many many miles of wires and pylons crossing farmland for regular terrestrial grids already. A rectenna looks more like a mesh than a set of panels: the idea is that the visible light spectrum passes through and the target microwave frequencies don't, so unlike a photovoltaic solar farm the land underneath is fine for farming. Nominally the land is safe to be occupied or passed through by humans too, although they might take some convincing. It becomes a problem when people start trying to get the rectennae banned...
Dylan16807 2mo ago
> it turns out that, compared to beaming power from space, it's projected to be cheaper to move compute upwell instead This is damning with the faintest of praise. Beaming power from space is a terrible idea.
laughing_man 2mo ago
Everybody keeps talking about cheap, clean power. But where I live the price of power has gone up dramatically in recent years. Free power (well, marginally free, anyway) is a major plus.
- wazoox 2mo ago
  In France, where we have relatively cheap and clean energy, they plan to build GW DCs with GWs setups of diesel backup generators. When these will run, the pollution will be staggering.

rayiner 2mo ago

> Is my borderline childish understanding of basic physics THAT off because I cannot see the value or utility (beyond a small smear of niche edge cases) of space-based compute? In the real world, "physics" is not necessarily the gating factor. There is a major concern about the environmental footprint of terrestrial data centers, to the point where major U.S. states are enacting moratoriums: https://www.governor.ny.gov/news/first-statewide-moratorium-new-hyperscale-data-centers-launched-governor-kathy-hochul https://www.governor.ny.gov/news/first-statewide-moratorium-.... These legal and social roadblocks must be accounted for in analyzing the viability of orbital data centers.

OneDonOne 2mo ago
If the "physics" tells you that your satellite cannot radiate heat away from your nVidia GPU cluster because each H100 needs 1.1 meter square of radiator, then opinions do not matter. The same applies to power supply and bandwidth.
- pfdietz 2mo ago
  What are the assumptions behind that 1.1 m^2 figure?
  - alephnerd 2mo ago
    OP is quoting Mikhail Klassen at Planet Labs [0]. The cost of replacement is exorbitant for commercial usecases, but is acceptable for defense usecases. The issue is too many people are looking at the commercial usecase while ignoring the defense usecase that is what is actually driving the conversation and dealflow in this segment. [0] - https://www.mikhailklassen.com/posts/orbital-data-centers/orbital-data-centers/ https://www.mikhailklassen.com/posts/orbital-data-centers/or...
    - pfdietz 2mo ago
      Ok, there are at least two bad assumptions there. First, it assumes the radiator is at the same temperature as the GPU. But radiators become dramatically more effective as temperature increases, with radiated power increasing as the fourth power of absolute temperature. So a heat pump that drives the radiator at higher temperature could make the radiator far smaller. More power would be required (and the radiator would have to radiate this energy too) but the radiator could become much smaller. The other problem is assuming the radiator is intercepting sunlight. But it can be shaded by reflective films or kept edge-on to the Sun.