Comment by energywut
1 day ago
Putting a datacenter in space is one of the worst ideas I've heard in a while.
Reliable energy? Possible, but difficult -- need plenty of batteries
Cooling? Very difficult. Where does the heat transfer to?
Latency? Highly variable.
Equipment upgrades and maintenance? Impossible.
Radiation shielding? Not free.
Decommissioning? Potentially dangerous!
Orbital maintenance? Gotta install engines on your datacenter and keep them fueled.
There's no upside, it's only downsides as far as I can tell.
> Reliable energy? Possible, but difficult -- need plenty of batteries
I can see it now - orbiting crypto mines power on at dawn, die off at dusk, Oscar-7 style
Yes cooling is difficult. Half the "solar panels" on the ISS aren't solar panels but heat radiation panels. That's the only way you can get rid of it and it's very inefficient so you need a huge surface.
This isn’t true. The radiators on ISS are MUCH smaller than the solar panels. I know it’s every single armchair engineer’s idea that heat rejection is this impossible problem in space, but your own example of ISS proves this is untrue. Radiators are no more of a problem than solar panels.
The radiators are significantly smaller than the PV arrays, but not by a massive ratio; looks like about 1:3.6 based on the published area numbers that I could find.
It looks like the ISS active cooling system has a maximum cooling capacity that could handle the equivalent of a single-digit number of racks (down to 1 for an AI-focused rack).
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The heat load of the ISS is a handful of astronauts and some equipment and whatever it absorbs from the sun. Not an entire data center or a nuclear rocket which is where the radiator discussion comes into play.
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seems oddly paradoxical. ISS interior at some roughly livable temperature. Exterior is ... freakin' space! Temperature gradient seems as if it should take of it ...
... and then you realize that because it is space, there's almost nothing out there to absorb the heat ...
There's nothing paradoxical about it. There's no such thing as a temperature gradient in a vacuum, there's nothing to hold or measure temperature against. And thus a vacuum is a really good insulator. Which is why a vacuum flask, which ultimately became one of Thermos' most well known products, is used to control temperature both in and outside the lab.
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there literally is nothing to absorb the heat. Conduction and convection are out, all you got is radiation.
new vc rule: no investing in space startups unless their founders have 1000 hours in KSP and 500 hours in children of a dead earth
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A great interactive example of this is the game Oxygen Not Included. By the late game, you're biggest problem is your base getting too hot from the waste heat of all your industry.
If you read the Starcloud whitepaper[1], it claims that massive batteries aren't needed because the satellites would be placed in a dawn-dusk sun-synchronous orbit. Except for occasional lunar eclipses, the solar panels would be in constant sunlight.
The whitepaper also says that they're targeting use cases that don't require low latency or high availability. In short: AI model training and other big offline tasks.
For maintenance, they plan to have a modular architecture that allows upgrading and/or replacing failed/obsolete servers. If launch costs are low enough to allow for launching a datacenter into space, they'll be low enough to allow for launching replacement modules.
All satellites launched from the US are required to have a decommissioning plan and a debris assessment report. In other words: the government must be satisfied that they won't create orbital debris or create a hazard on the ground. Since these satellites would be very large, they'll almost certainly need thrusters that allow them to avoid potential collisions and deorbit in a controlled manner.
Whether or not their business is viable depends on the future cost of launches and the future cost of batteries. If batteries get really cheap, it will be economically feasible to have an off-the-grid datacenter on the ground. There's not much point in launching a datacenter into space if you can power it on the ground 24/7 with solar + batteries. If cost to orbit per kg plummets and the price of batteries remains high, they'll have a chance. If not, they're sunk.
I think they'll most likely fail, but their business could be very lucrative if they succeed. I wouldn't invest, but I can see why some people would.
1. https://starcloudinc.github.io/wp.pdf
You can also drink from a shoe. It's absolutely possible.
And it enjoyed some popularity. [1]
[1] https://en.wikipedia.org/wiki/Beer_boot
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> For maintenance, they plan to have a modular architecture that allows upgrading and/or replacing failed/obsolete servers. If launch costs are low enough to allow for launching a datacenter into space, they'll be low enough to allow for launching replacement modules.
This is hiding so, so much complexity behind a simple hand wavy “modular”. I have trained large models on thousands of GPUs, hardware failure happen all the time. Last example in date: an infiniband interface flapping which ultimately had to be physically replaced. What do you do if your DC is in space? Do you just jettison the entire multi million $ DGX pod that contains the faulty 300$ interface before sending a new one? Do you have an army of astronauts + Dragons to do this manually? Do we hope we have achieve super intelligence by then and have robots that can do this for us ?
Waving the “Modular” magic key word doesn’t really cut it for me.
> Whether or not their business is viable depends on the future cost of launches and the future cost of batteries. If batteries get really cheap, it will be economically feasible to have an off-the-grid datacenter on the ground. There's not much point in launching a datacenter into space if you can power it on the ground 24/7 with solar + batteries.
Something tells me that the price of batteries is already cheap enough for terrestrial data centers to make more economic sense than launching a datacenter - which will also need batteries - into space.
Same with hydrogen fuel cell vehicles, inventing a detour because it sounds cool and ultimately don't work out because Occam's Razor.
Let me alert all the NIMBY folks, let them know that data centers will be blocking their view of the moon and casting shadows on their backyards.
Just give all those astronomers mockup telescopes with little screens creating the fancy images they want inside them.
They will calm down.
Of course, they're soft targets in space war too, they could generate lots of debris.
Man I read “AI training in a high latency self sufficient satellite orbiting earth” as the start of a Sci-Fi novel…
Just another good proof of paper being an ideal medium for fiction
Any purported advantages have to contend with the fact that sending the modules costs millions of dollars. Tens to hundred millions
Servers outside any legal jurisdiction. Priceless.
International space law (starting with the Outer Space Treaty of 1967) says that nations are responsible for all spacecraft they launch, no matter whether the government or a non-governmental group launches them. So a server farm launched by a Danish company is governed by Danish law just the same as if they were on the ground- and exposed to the same ability to put someone into jail if they don't comply with a legal warrant etc.
This is true even if your company moves the actual launching to, say, a platform in international waters- you (either a corporation or an individual) are still regulated by your home country, and that country is responsible for your actions and has full enforcement rights over you. There is no area beyond legal control, space is not a magic "free from the government" area.
While that's all true, it does hilariously increase the difficulty for the government showing up and seizing your server hardware...
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What if you’re a stateless person? (Not an easy status to acquire these days, but any US citizen can just renounce their citizenship without getting a new one, for example.)
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nations are responsible for all spacecraft they launch, no matter whether the government or a non-governmental group launches them.
Nations come and go. In my lifetime, the world map has changed dozens of times. Incorporate in a country that doesn't look like it's going to be around very long. More than likely, the people running it will be happy to take your money.
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:-) I appreciate your snark and the ad campaign reference.
But if international waters isn't enough (and much cheaper) then I don't think space will either. Man's imagination for legal control knows no bounds.
You wait (maybe not, it's a long wait...), if humankind ever does get out to the stars, the legal claims of the major nations on the universe will have preceded them.
The 'Principality of Sealand', anywhere else on the high seas or Antarctica have their issues with practicality too, but considerably less likelihood of background radiation flipping bits...
Unless the company blasts its HQ and all its employees into space, no, they are very much subject to the jurisdiction of the countries they operate in. The physical location of the data center is irrelevant.
Exactly. Government entities have a funny habit of making their own decisions about what (and who) is and is not subject to their jurisdiction.
[Mild spoilers for _Critical Mass_ by Daniel Suarez below]
> Servers outside any legal jurisdiction
Others have weighed in on the accuracy of this, with a couple pointing out that the people are still on the ground. There's a thread in _Critical Mass_ by Daniel Suarez that winds up dealing with this issue in a complex set of overlapping ways.
Pretty good stuff, I don't think the book will be as good as the prior book in the series. (I'm only about halfway through.)
I know there's the fantasy of orbital CSAM storage able to beam obscenity to any point on the ground with zero accountability, but that is not going to survive real world politics.
Given that most of the major powers have satellite shootdown ability this isn't worth all that much if you're causing enough trouble.
Shooting down a satellite is a major step that creates a mess of space junk, angering everybody.
Plus you can just have a couple of politicians from each major power park their money on that satellite.
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Who would be willing to provide connectivity to servers that are exploiting being outside legal jurisdiction for some kind of value?
Dozens upon dozens of illicit shady bulletproof hosting providers.
2026, we will get ransomware from space!
The RaaS groups have hundreds of millions of dollars so in theory they actually could get something like that setup if they wanted.
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Anyone with a ground station aimed at the datacenter satellite.
Pretty worthless unless the execs live in space too.
Why? Its not like we put execs in jail for allowing their companies to do terrible things under their watch.
Would be cheaper to do in international waters, even if you needed security to protect it.
The best argument I've heard for data centres in space startups is it's a excuse to do engineering work on components other space companies might want to buy (radiators, shielding, rad-hardened chips, data transfer, space batteries) which are too unsexy to attract the same level of FOMO investment...
Yes, and also just because a space data center isn’t useful today doesn’t mean it won’t be required tomorrow. When all the computing is between the ground and some nearby satellites, of course the tradeoffs won’t be worth it.
But what about when we’re making multi-year journeys to Mars and we need a relay network of “space data centers” talking to each other, caching content, etc?
We may as well get ahead of the problems we’ll face and solve them in a low-stakes environment now, rather than waiting to discover some novel failure scenario when we’re nearing Mars…
> what about when we’re making multi-year journeys to Mars and we need a relay network of “space data centers” talking to each other, caching content, etc?
How would this work? Planets orbit at different speeds, so you can't build a chain of relays to another planet. I can imagine these things orbiting planets, but is that worth it compared to ground-based systems?
We'd build it then? The problems of a space data center are extremely generic and only worth solving when you actually need one. Which would never be in low earth orbit.
You need less batteries in orbit than on the ground since you're only in shade for at most like 40 minutes. And it's all far more predictable.
Cooling isn't actually any more difficult than on Earth. You use large radiators and radiate to deep space. The radiators are much smaller than the solar arrays. "Oh but thermos bottles--" thermos bottles use a very low emissivity coating. Space radiators use a high emissivity coating. Literally every satellite manages to deal with heat rejection just fine, and with radiators (if needed) much smaller than the solar arrays.
Latency is potentially an issue if in a high orbit, but in LEO can be very small.
Equipment upgrades and maintenance is impossible? Literally, what is ISS, where this is done all the time?
Radiation shielding isn't free, but it's not necessarily that expensive either.
Orbital maintainence is not a serious problem with low cost launch.
The upside is effectively unlimited energy. No other place can give you terawatts of power. At that scale, this can be cheaper than terrestrially.
> The radiators are much smaller than the solar arrays.
Modern solar panels are way more efficient than the ancient ones in ISS, at least 10x. The cooling radiators are smaller than solar panels because they are stacked and therefore effectively 5x efficient.
Unless there are at least 2x performance improvements on the cooling system, the cooling system would have to be larger than solar panels in a modern deployment.
This is false. It’s pretty straightforward to prove using Stefan-Boltzmann. Radiating from both sides at 300K, a square radiator that’s 1 meter on a side emits 920W.
Additionally, you wouldn’t use cutting edge 35% triple junction cells for a space datacenter, you’d use silicon cells like Starlink and ISS use. 22% efficient with 90% full factor, given 1350W/m^2 and thus 270W/m^2, to provide enough power for that radiator you’d need a solar panel 3.4 times as big, and that’s if you were in 24/7 sunshine. If you’re in a low orbit that’s obscured almost half the time, it’s 6-7 times as big.
Why do people keep making these obviously wrong claims when a paragraph of arithmetic shows they’re wrong? Do the math.
We’re probably thinking of it the wrong way. Instead of a single datacenter it’s more likely we build constellations and then change the way we write software.
There will probably be a lot more edge computing in the future. 20 years ago engineers scoffed at the idea of deploying code into a dozen regions (If you didn’t have a massive datacenter footprint) but now startups do it casually like it’s no big deal. Space infrastructure will probably have some parallels.
That sounds like the Guoxing Aerospace / ADA Space “Three-Body Computing Constellation”, currently at 12 satellites (out of a planned 2,800).
The Chinese project involves a larger number of less powerful inference-only nodes for edge computing, compared to Starcloud's training-capable hyperscale data centers.
[1] Andrew Jones. "China launches first of 2,800 satellites for AI space computing constellation". Spacenews, May 14, 2025. https://spacenews.com/china-launches-first-of-2800-satellite... [2] Ling Xin. "China launches satellites to start building the world’s first supercomputer in orbit". South China Morning Post, May 15, 2025. https://www.scmp.com/news/china/science/article/3310506/chin... [3] Ben Turner. "China is building a constellation of AI supercomputers in space — and just launched the first pieces". June 2, 2025. https://www.livescience.com/technology/computing/china-is-bu...
> 20 years ago engineers scoffed at the idea of deploying code into a dozen regions (If you didn’t have a massive datacenter footprint) but now startups do it casually like it’s no big deal.
Are there many startups actually taking real advantage of edge computing? Smaller B2B places don't really need it, larger ones can just spin up per-region clusters.... and then for 2C stuff you're mainly looking at static asset stuff which is just CDNs?
Who's out there using edge computing to good effect?
I think the upside is that it’s VC fodder. I imagine their thinking went about as far as “wow, what if we like….did AI…but in space?!”
Sounds like a great investment for SoftBank
You're making lots of assumptions. They can put like 1000 Raspberrypi's which don't need all that much cooling and relatively little energy requirements.
For your other concerns, the risks are worth it for customers because of the main reward: No laws or governments in space! Technically, the datacenter company could be found liable but not for traffic, only for take-down refusals. Physical security is the most important security. For a lot of potential clients, simply making sure human access to the device is difficult is worth data-loss,latency and reliability issues.
reliable energy is the only (maybe valid) reason. you can get yourself into a sun synchronous dawn dusk orbit and avoid shading by the earth.
Bandwidth - negligible
Re: reliable energy. Even in low earth orbit, isn't sunlight plentiful? My layman's guess says it's in direct sun 80-95% of the time, with deterministic shade.
It's super reliable, provided you've got the stored energy for the reliable periods of downtime (or a sun synchronous orbit). Energy storage is a solved problem, but you need rather a lot of it for a datacentre and that's all mass which is very expensive to launch and to replace at the end of its usable lifetime. Same goes for most of the other problems brought up
Exactly this. It's not that it's a difficult problem, but it is a high mass-budget problem. Which makes it an expensive problem. Which makes it a difficult problem.
You answered it yourself, a sun synchronous orbit negates the need for large battery systems.
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Depends on your orbit, but you need to be prepared to rotate into Earth's shadow seamlessly.
> There's no upside, it's only downsides as far as I can tell.
It's outside of any jurisdiction, this is a dream come true for a libertarian oligarch.
It's not, all objects in space fall under the jurisdiction of the country that launched the rocket.