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Also, Pixxel, Skyroot, and Agnikul are targeting orbital data center launches this year for defense applications (which is what the entire ODC story is about).

Also, Pixxel, Skyroot, and Agnikul are targeting orbital data center launches this year for defense applications (which is what the entire ODC story is about). The US NRO already uses India's Pixxel [0] along with Finland's ICEYE (which is now co-manufacturing synthetic aperture sats in India with Agnikul [1]) for hyperspectral scanning. Edit: can't reply > But.. why? Missile Defense and C4ISR [2]. Seconds matter, so most of the newer generation of missile defense systems are experimenting with how to offload compute at the edge to reduce C2 latency. Most orbital sat startups in the US, China, and India are partially backed by military and intel oriented funds (eg. Starcloud and IQT/In-Q-Tel). ----- [0] - https://www.nro.gov/news-media-featured-stories/news-media-press-releases/Archived-Press-Releases/Press-Release-Article/Article/4476860/nro-partners-with-new-vendors-to-boost-multi-phenomenology-capabilities/ https://www.nro.gov/news-media-featured-stories/news-media-p... [1] - https://www.livemint.com/companies/news/agnikul-cosmos-iceye-space-startups-india-11782805545828.html https://www.livemint.com/companies/news/agnikul-cosmos-iceye... [2] - https://idsa.in/wp-content/uploads/2026/01/book-MISSION-SUDARSHAN-CHAKRA-2026.pdf https://idsa.in/wp-content/uploads/2026/01/book-MISSION-SUDA...

detritus 3mo ago
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 3mo 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 3mo ago
    Could we have giant nuclear reactors in space? What's the power loss from beaming down power?
    - TeMPOraL 3mo 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 3mo 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 3mo ago
      We already have a giant fusion reactor in space
      - TeMPOraL 3mo 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.
- rayiner 3mo 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 3mo 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 3mo ago
      What are the assumptions behind that 1.1 m^2 figure?
      - alephnerd 3mo 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 3mo 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.
OneDonOne 3mo ago
This borders on science fiction. 88,000-and 1-million satellite clusters (as claimed in your link) are hard to take seriously, especially with the possibility of Kessler Syndrome. Also: 1. How do you cool your chips? Vacuum is a thermal insulator, so radiators are required to remove heat. nVidia (or even ASICs) require much and specialised cooling. 2. How does one radiation harden a H100? 3. I'm also seeing where TCO for these are 78x their terrestrial equivalents [0]. Is that financial sustainable? And there still remain issues with power supply, regulations, and bandwidth. This feels more like a thought experiment rather than an actual serious engineering or business case. [0] https://www.abiresearch.com/blog/data-centers-in-space https://www.abiresearch.com/blog/data-centers-in-space
- alephnerd 3mo ago
  The projections are questionable, but this is something the US and China are experimenting with as well. 1 and 2 are still open questions, but these are not aimed to be commercial grade DCs - this is basically edge compute (think a handful of racks). 3 is not a problem for defense usecases. (EDIT: Discussion here seems to point out that data OP is using might be flawed [1]). Ignoring the fact that just about every orbital data center startup in the US is funded by IQT and China's CMF has been doing something similar is bad from a defense perspective. Based on dealflow, these aren't being targeted for consumer usecases in the short-term and whoever has been saying that is misleading. > especially with the possibility of Kessler Syndrome... India, Russia, China, and the US don't care about Kessler Syndrome - they have already launched and deployed ASATs. This also comes after India and China had a near collision in 2024 that was treated as an offensive action [0]. [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... [1] - https://news.ycombinator.com/item?id=49039873 https://news.ycombinator.com/item?id=49039873
  - OneDonOne 3mo ago
    This reminds me of the railgun. Basic math and physics tells us that not only would the (very expensive) barrels wear out very quickly, but that it would have had to be fitted on on a nuclear-powered pocket battlecruiser. Worse, the technology for firing any meaningful payloads from an electric gun (8" Small Diameter Bomb equivalents, guided, airburst, incendiary) simply does not exist. Same as with Musk's California Vacuum Tunnel (which diverted attention from passenger rail). And his Neuralink. In the 1980s, it was nuclear pumped space-based lasers and Soviet particle beam weapons. All of the above can be debunked with 2 years undergrad physics and a Casio calculator. Yet they were still taken seriously by high-level politicians and business, some of whom were deeply connected with the military-industrial complex. People have shrugging of questions like 1 and 2, only for 3 to hit them very hard. But we will see if they can launch 600 of these satellites as they claim.
WalterBright 3mo ago
> targeting orbital data center launches I am regularly assured by HN denizens that orbiting data centers will never work.
- alephnerd 3mo ago
  Because they won't for commercial usecases (which was never the point of an ODC). For C4ISR usecases they solve the latency problem and are worth the spend needed. Everyone on HN is talking about a commercial usecase that isn't under serious consideration.
  - WalterBright 3mo ago
    What I repeatedly read here was it is physically not possible to build an ODC because of heat problems and alpha particle problems.
    - alephnerd 3mo ago
      At 1GW scale, I'd agree. But if you need around 40-50 racks to do image processing and alerting, that's largely a solved problem. The whole thesis around ODCs is to basically mass deploy a bunch of replaceable racks en masse and consistently, such that any geospatial intel can be processed at the edge.
  - laughing_man 3mo ago
    It's funny, people here said the same thing about Starlink. "Sure, it's technically possible, but you could only lose money by doing something like that. There's just no market for it."

detritus 3mo ago

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 3mo 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 3mo ago
  Could we have giant nuclear reactors in space? What's the power loss from beaming down power?
  - TeMPOraL 3mo 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 3mo 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 3mo ago
    We already have a giant fusion reactor in space
    - TeMPOraL 3mo 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.
rayiner 3mo 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 3mo 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 3mo ago
    What are the assumptions behind that 1.1 m^2 figure?
    - alephnerd 3mo 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 3mo 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.

OneDonOne 3mo ago

This borders on science fiction. 88,000-and 1-million satellite clusters (as claimed in your link) are hard to take seriously, especially with the possibility of Kessler Syndrome. Also: 1. How do you cool your chips? Vacuum is a thermal insulator, so radiators are required to remove heat. nVidia (or even ASICs) require much and specialised cooling. 2. How does one radiation harden a H100? 3. I'm also seeing where TCO for these are 78x their terrestrial equivalents [0]. Is that financial sustainable? And there still remain issues with power supply, regulations, and bandwidth. This feels more like a thought experiment rather than an actual serious engineering or business case. [0] https://www.abiresearch.com/blog/data-centers-in-space https://www.abiresearch.com/blog/data-centers-in-space

alephnerd 3mo ago
The projections are questionable, but this is something the US and China are experimenting with as well. 1 and 2 are still open questions, but these are not aimed to be commercial grade DCs - this is basically edge compute (think a handful of racks). 3 is not a problem for defense usecases. (EDIT: Discussion here seems to point out that data OP is using might be flawed [1]). Ignoring the fact that just about every orbital data center startup in the US is funded by IQT and China's CMF has been doing something similar is bad from a defense perspective. Based on dealflow, these aren't being targeted for consumer usecases in the short-term and whoever has been saying that is misleading. > especially with the possibility of Kessler Syndrome... India, Russia, China, and the US don't care about Kessler Syndrome - they have already launched and deployed ASATs. This also comes after India and China had a near collision in 2024 that was treated as an offensive action [0]. [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... [1] - https://news.ycombinator.com/item?id=49039873 https://news.ycombinator.com/item?id=49039873
- OneDonOne 3mo ago
  This reminds me of the railgun. Basic math and physics tells us that not only would the (very expensive) barrels wear out very quickly, but that it would have had to be fitted on on a nuclear-powered pocket battlecruiser. Worse, the technology for firing any meaningful payloads from an electric gun (8" Small Diameter Bomb equivalents, guided, airburst, incendiary) simply does not exist. Same as with Musk's California Vacuum Tunnel (which diverted attention from passenger rail). And his Neuralink. In the 1980s, it was nuclear pumped space-based lasers and Soviet particle beam weapons. All of the above can be debunked with 2 years undergrad physics and a Casio calculator. Yet they were still taken seriously by high-level politicians and business, some of whom were deeply connected with the military-industrial complex. People have shrugging of questions like 1 and 2, only for 3 to hit them very hard. But we will see if they can launch 600 of these satellites as they claim.

WalterBright 3mo ago

> targeting orbital data center launches I am regularly assured by HN denizens that orbiting data centers will never work.

alephnerd 3mo ago
Because they won't for commercial usecases (which was never the point of an ODC). For C4ISR usecases they solve the latency problem and are worth the spend needed. Everyone on HN is talking about a commercial usecase that isn't under serious consideration.
- WalterBright 3mo ago
  What I repeatedly read here was it is physically not possible to build an ODC because of heat problems and alpha particle problems.
  - alephnerd 3mo ago
    At 1GW scale, I'd agree. But if you need around 40-50 racks to do image processing and alerting, that's largely a solved problem. The whole thesis around ODCs is to basically mass deploy a bunch of replaceable racks en masse and consistently, such that any geospatial intel can be processed at the edge.
- laughing_man 3mo ago
  It's funny, people here said the same thing about Starlink. "Sure, it's technically possible, but you could only lose money by doing something like that. There's just no market for it."