Economics of Orbital vs. Terrestrial Data Centers(andrewmccalip.com) |
Economics of Orbital vs. Terrestrial Data Centers(andrewmccalip.com) |
It is a nice talking point for the U.S. Saudi Investment Forum. The Saudis apparently buy anything:
Have we seen any benefits to orbital computing by launching a cluster of raspberry pis to LEO? Surely this isn't an impossible task to test out on a smaller scale?
There have been NVIDIA Jetsons or better on orbit since at least 2021 and that had no meaningful impact on any actual meaningful compute workloads beyond proof of concept demos.
But when I click on it, I get this error.
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I suspect it is about the regulatory environment. The regulatory environment on data centers is moving quickly. Data centers used to be considered a small portion of the economy and thus benign and not worth extorting/controlling. This seems to be changing, rapidly.
Given that data centers only exchange information with their consumers they are a natural candidate for using orbit as a way to escape regulators.
Further, people are likely betting that regulators will take considerable time to adjust since space is multinational.
My point is that you can actually reduce it all to dollars. And I believe that the cost of orbital data centers will come down due to technological advances, while the cost of regulation will only go up, because of local and global opposition.
I'm not sure. A couple of points:
1) The regulatory landscape is enormous. It is unknown from which angle regulators will "slow you down."
2) As I mentioned the regulatory frameworks in this area are evolving very quickly. It is unknown what the regulations will be in 1, 2, 5 years and how that will impact your business.
It’s a bit like the cyberpunk future when the ultra riches live in moon bases or undersea bases and ordinary people fight for resources in a ruined earth.
But oddly this doesn't seem to be how the concept is typically framed.
My second level curiosity is how much cheaper/competitive it'd be if we had space elevators.
I suppose there are several other Oligarchs In Space stories and movies since then, but if the point of the space station is to host AI, that narrows it down a bit.
Or perhaps it's performative, designed to spook gullible politicians into changing laws to "keep" businesses that were never actually going to go somewhere else anyway.
Someone might be foreseeing an scenario like that? Are satellite launchers behind this hype?
- Ludicrously expensive to setup
- Need radiation-hardened silicon
- Ludicrously expensive maintenance requiring highly specialized operators (a.k.a astronauts)
- High risk of losing the entire equipment to a rocket failure (not infrequent even for modern launch vehicles)
- Supplying enough electrical power would be extremely difficult
- Cooling would be extremely difficult
- Geosynchronous orbits have at least 200ms of communication latency
- Lower orbits means the data center would not stay in place and require complicated tracking antennae and/or a communication mesh a la Starlink, again increasing latency and complexity
Pros of orbital data centers:
- ??????
...why are we doing this again?
and can not be compared to anything else
Americans couldn't shoot at it in fear of igniting a space war with China.
I 100% agree with this. There are ~2,600 billionaires in the world and we should encourage all of them to spend their money. Even buying a superyacht is a benefit to the economy. But the best billionaires, like Bill Gates and Elon Musk, are actually trying to advance the tech tree.
We are honestly lucky that Musk is wired funny. Any normal human being would retire and hang out on the beach with supermodels after all the abuse he has taken. But he takes it all as a personal challenge and doubles down. That is both his worst quality and his best.
"I'll go one step further and say the quiet part out loud: we should be actively goading more billionaires into spending on irrational, high-variance projects that might actually advance civilization. I feel genuine secondhand embarrassment watching people torch their fortunes on yachts and status cosplay. No one cares about your Loro Piana. If you've built an empire, the best possible use of it is to burn its capital like a torch and light up a corner of the future. Fund the ugly middle. Pay for the iteration loops. Build the cathedrals. This is how we advance civilization."
That can be done easily (and has been done many times in the past! And in the present, elsewhere in the world outside the US!) by TAXING the billionaires and using that money for government funded research programs such as DARPA, NSF, national space programs that are actually ambitious and risk taking and held to timelines.
Americans need to get over this idea that billionaires are gods that we must pray to and instead see them as just normal citizens who need to be taxed way more.
https://taranis.ie/datacenters-in-space-are-a-terrible-horri...
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If I were to guess, my first bet would be grand PR damage control for all the Mexicans, Irish, and what have you as in “don’t worry, we’ll soon be in space and out of your backyard” (no, they won’t).
https://www.nytimes.com/2025/10/20/technology/ai-data-center...
First, he seeks and creates conflict. He isn't 'taking' abuse, except in the sense that he is reaching out and grasping at it.
Everyone in that position takes lots of abuse. If they built their own fortune, they generally don't retire to the beach or they would have long ago.
But I think we'd be better off if taking a political position did not automatically piss off half the country. I think a lot of competent but normal people refuse the get involved in politics because of how toxic it is.
I wish Musk had stayed out of politics, but I'm glad he hasn't given up on Tesla/SpaceX just because of the enemies he's made. I think any normal person would have.
You’re falling victim to the ‘broken windows fallacy’ here; money which is invested is actually more productive in improving medium and long term economic productivity than ‘consumption’ goods. Even ‘retained’ money (under one’s mattress) is not net-negative, as it increases the value of its circulating counterparts.
Scenario B: A homeowner adds a new window to their home.
Scenario C: A homeowner buys an online-course to learn how to make windows and then adds one to their home.
Scenario A has approximately no benefit to the economy. The homeowner is no better off (same number of windows) but had to spend money. The window maker might be better off, but only to the same extent that the homeowner is worse off.
I totally agree that Scenario A is not a benefit to the economy. That's the "broken window fallacy".
But Scenario B is definitely better for the economy. The homeowner has decided that having a new window is better than having the money. So the homeowner is better off. The window maker is also better off because they get the money. This is what happens when a billionaire buys a yacht.
Scenario C is the best. The homeowner has a new skill, which they can use to add more windows to their house or maybe their neighbors' houses. Over time, the amount of money spent on window-making will decrease, but the number of windows will stay constant or increase. That's a net benefit. And the online-course creator still made money.
This is what Musk is doing. He is developing new technologies that enable new capabilities and/or make existing things cheaper (e.g., electric cars, access to space, rural internet connectivity).
There is also Scenario D: The homeowner doesn't buy a new window but just keeps his money under his mattress. This is clearly the worst for the economy. Hording money like that means that there is less money circulating and lowered economic activity. The window maker is worse off, and even the homeowner is worse off if they would like to have a new window.
Billionaires who don't spend their money are the real danger, not the ones who tweet too much.
Investing their money is slightly better in that it makes the price of borrowing cheaper. But that only helps up to a point. Someone has to spend money or else there's no point in being able to borrow some. So I wish more billionaires were following Scenario C.
https://finance.yahoo.com/news/musks-net-worth-hits-600-2022...
He is a walking billboard.
Is the hope that Elon or fans of his read it and get offended? I doubt they care much, and I fail to see the point of it.
That's not true for people experienced in the particular industry. Others can find a lawyer that will give them a good picture.
Scenario D: A homeowner adds 10 window to their home because the populous think he is stingy and will send him to the guillotine if he does not start spending his money on new windows!
Scenario D provides no benefit to society.
If the billionaire does want the yacht, then no encouragement is needed.
He's been possibly the world's leading troll since long before his MAGA phase. Let's be serious.
Diminishing names used for delegitimization are not something reddit invented. Calling George W. Bush "dubya", Barack Obama "barry", or Richard Nixon "look it up" are all great examples of a time-honored tradition.
Hope I cleared that up for you.
Its like that scene at the end of Real Genius, "Maybe somebody already has a use for it, one for which it's perfectly designed." Lets look at the facts: Impossible to raid, not under any direct legal jurisdiction, high bandwidth line of sight communications options to satellite feed points that would be difficult to tap outside of other orbital actors, Power feed that is untethered to any planetary grid or at risk of terrestrial actors, etc.
It's definitely much easier and much much cheaper to send a single rocket there blowing the assembled rather large target into still sizeable chucks of orbital debris than it is to deploy and assemble the thing there in the first place. And there are a few terrestrial actors rather capable of this. More than there are who could make it happen under whatever optimistic assumptions anyway.
In itself, a structure of this size in orbit is an efficient catcher of micrometeorites and orbital debris. Over "non-eternal" timeframes you don't even need a bad actor with good rockets.
Nevermind that in such a case, the eventual fate of these sizeable chunks of orbital debris is to become rods of god ... just without particular steerability.
It'd be a sight.
At any rate, one basic communication's satellite worth of compute would be more than enough. No need for TPUs.
The article makes this point, but it's relatively far in and I felt it was worth making again.
With that said, my employer now appears to be in this business, so I guess if there's money there, we can build the satellites. (Note: opinions my own) I just don't see how it makes sense from a practical technical perspective.
Space is a much harder place to run datacenters.
If it was just about cooling and power availability, you'd think people would be running giant solar+compute barges in international waters, but nobody is doing that. Even the "seasteading" guys from last decade.
These proposals, if serious, are just to avoid planning permission and land ownership difficulties. If unserious, it's simply to get attention. And we're talking about it, aren't we?
In general I don't understand this line of thinking. This would be such a basic problem to miss, so my first instinct would be to just look up what solution other people propose. It is very easy to find this online.
I've always enjoyed thinking about this. Temperature is a characteristic of matter. There is vanishingly little matter in space. Due to that, one could perhaps say that space, in a way of looking at it, has no temperature. This helps give some insight into what you mention of the difficulties in dealing with heat in space - radiative cooling is all you get.
I once read that, while the image we have in our mind of being ejected out of an airlock from a space station in orbit around Earth results in instant ice-cube, the reality is that, due to our distance from the sun, that situation - ignoring the lack of oxygen etc that would kill you - is such that we would in fact die from heat exhaustion: our bodies would be unable to radiate enough heat vs what we would receive from the sun.
In contrast, were one to experience the same unceremonious orbital defenestration around Mars, the distance from the sun is sufficient that we would die from hypothermia (ceteris paribus, of course).
Budget the solar panel area as a function of the maximum computational load.
The rest of the satellite must be within the shade of the solar panel, so it basically only sees cold space, so we need a convex body shape, to insure that every surface of the satellite (ignoring the solar panels) is radiatively cooling over its full hemisphere.
So pretend the sun is "below", the solar panels are facing down, then select an extra point above the solar panel base to form a pyramid. The area of the slanted top sides of the pyramid are the cooling surfaces, no matter how close or far above the solar panels we place this apex point, the sides will never see the sun because they are shielded by the solar panel base. Given a target operating temperature, each unit surface area (emissivity 1) will radiate at a specific rate, and we can choose the total cooling rate by making the pyramid arbitrarily long and sharp, thus increasing the cooling area. We can set the satellite temperature to be arbitrarily low.
Forget the armchair "autodidact" computer nerds for a minute
Temperature: NaN °C
The universe is filled with such a bath of radiation, so it makes sense to say the temperature of space is the temperature of this bath. Of course, in galaxies, or even more so near stars, there's additional radiation that is not in thermal equilibrium.
And yes, obviously they aren't moving in the same way, but it's still kind of weird to think about.
• No additional mass for liquid cooling loop infrastructure; likely needed but not included
• Thermal: only solar array area used as radiator; no dedicated radiator mass assumed
Overall not a great model. But on the other hand, even an amateur can use this model and imagine that additional parts and costs are missing, so if it's showing a bad outlook even in the favorable/cheating conditions for space DCs, then they are even dumber idea if all costs would be factored in fully. Unfortunately many serious journalists can't even do that mental assumption. :(
Solar panels have improved more than cooling technology since ISS was deployed, but the two are still on the same order of magnitude.
Or a 3.651 km squared and 2.581 km squared butterfly sattelite.
I don't think your cooling area measures account for the complications introduced by scale.
Heat dissipation isn't going to efficiently work its way across surfaces at that scale passively. Dissipation will scale very sub-linearly, so we need much more area, and there will need to be active fluid exchangers operating at speed spanning kilometers of real estate, to get dissipation/area anywhere back near linear/area again.
Liquid cooling and pumps, unlike solar, are meaningfully talked about in terms of volume. The cascade of volume, mass, complexity and increased power up-scaling flows back to infernal launch volume logistics. Many more ships and launches.
Cooling is going to be orders of magnitude more trouble than power.
How are these ideas getting any respect?
I could see this at lunar poles. Solar panels in permanent sunlight, with compute in direct surface contact or cover, in permanent deep cold shadow. Cooling becomes an afterthought. Passive liquid filled cooling mats, with surface magnifying fins, embedded in icy regolith, angled for passive heat-gradient fluid cycling. Or drill two adjacent holes, for a simple deep cooling loop. Very little support structure. No orbital mechanics or right-of-way maneuvers to negotiate. Scales up with local proximity. A single expansion/upgrade/repair trip can service an entire growing operation at one time, in a comfortable stable g-field.
Let’s say you need 50m^2 solar panels to run it, then just a ton of surface area to dissipate. I’d love to be proven wrong but space data centers just seem like large 2d impact targets.
Now JWST is at near L2 but it is still in sunlight. It's solar-powered. There are a series of radiating layer to keep heat away from sensitive instruments. Then there's the solar panels themselves.
Obviously an orbital data center wouldn't need some extreme cooling but the key takeaway from me is that the solar panels themselves would shield much of the satellite from direct sunlight, by design.
Absent any external heating, there's only heating from computer chips. Any body in space will radiate away heat. You can make some more effective than others by increasing surface area per unit mass (I assume). Someone else mentioned thermoses as evidence of insulation. There's some truth to that but interestingly most of the heat lost from a thermos is from the same IR radiation that would be emitted by a satellite.
So in terms of power density you're looking at about 3 orders of magnitude difference. Heating and cooling is going to be a significant part of the total weight.
Every conversation I've seen is despite how many serious organizations with talented people, the "uhhh how do you cool it?" Is brought up immediately
Everyone I talked to (and everyone on this forums) knows cooling is hard in space.
It is always the number one comment on every news piece that is featured here talking about "AI in space".
Compute is severely power-constrained everywhere except China, and space based datacenters is a way to get around that.
But there is no universe in which it's possible to build them economically.
Not even close. The numbers are simply ridiculous.
And that's not even accounting for the fact that getting even one of these things into orbit is an absolutely huge R&D project that will take years - by which time technology and requirements will have moved on.
As you intimated, the radiated heat Energy output of an object is described by the Stefan-Boltzmann Law, which is E = [Object Temp ]^4 * [Stefan-Boltzmann Constant]
However, Temp must be in units of an absolute temperature scale, typically Kelvin.
So the relative heat output of a 90C vs 20C objects will be (translating to K):
383^4 / 293^4 = 2.919x
Plugging in the constant (5.67 * 10^-8 W/(m^2*K^4)) The actual values for heat radiation energy output for objects at 90C and 20C objects is 1220 W/m^2 and 417 W/m^2
The incidence of solar flux must also be taken into account, and satellites at LEO and not in the shade will have one side bathing in 1361 W/m^2 of sunlight, which will be absorbed by the satellite with some fractional efficiency -- the article estimates 0.92 -- and that will also need to be dissipated.
The computer's waste heat needs to be shed, for reference[0] a G200 generates up to 700W, but the computer is presumably powered by the incident solar radiation hitting the satellite, so we don't need to add its energy separately, we can just model the satellite as needing to shed 1361 W/m^2 * 0.92 = 1252 W/m^2 for each square meter of its surface facing the sun.
We've already established that objects at 20C and 90C only radiate 1220 W/m^2 and 417 W/m^2, respectively, so to radiate 1252 W per square meter coming in from the sun facing side we'll need 1252/1220 = 1.026 times that area of shaded radiator maintained at a uniform 90C. If we wanted the radiator to run cooler, at 20C, we'd need 2.919x as much as at 90C, or 3.078 square meters of shaded radiator for every square meter of sun facing material.
[0] Nvidia G200 specifications: https://www.nvidia.com/en-us/data-center/h200/
> References: Gemini, Gemini, ChatGPT, ChatGPT, Gemini, ChatGPT, Gemini, ChatGPT, Grok, Gemini (There are sub-references from these services in the GitHub.)
I think, if you're going to make statements like this - especially from a position of expertise, you should be personally verifying the numbers and citing their sources directly. What good is asking the reader to trust an AI on your behalf? They should trust you.
(To be clear, I suspect the conclusions drawn are still correct.)
I'm going to assume there's tons of logical errors and oversights in the math, considering the author couldn't even be bothered to write the text of the post himself.
https://www.youtube.com/watch?v=d-YcVLq98Ew
The short of it is that cooling is likely the biggest problem, given you will need to pump the heat to the backside and radiate it away, and the amount of mass you will need to dedicate to cooling works against deployments and increases the cost per unit significantly. Not to mention, the idea of these huge deployments runs into potential space debris issues.
Whenever one of these ventures actually manages to launch a proof of concept, I think we'll be able to quickly discern if there is actually a near-future here.
If you can produce any kind of economically productive compute node and add it to (for example) the Starlink network, and launch on a reusable vehicle, you carry on installing them as fast as you can build them.
So, the move is to turn the problem of contested land use into a manufacturing problem.
This is not so easy to pin down on a spreadsheet, and will be decided at the level of the business unit. If SpaceX can put a GPU/TPU on the grid more economically than the other guy, then it doesn't matter if they have ammonia in the pipes instead of water.
Grab your popcorn.
> the list of organizations positioned to even try that is basically one.
Maaaaybe Blue Origin can join once they get a constellation going.
The one glaring hole that I see is the challenge of moving the data to/from the datacenter while it's on orbit. Bandwidth to/from space isn't free. FCC/ITU licenses are required, transmitters/receiviers/modems/DSP/antennas all add to SWAP (size, weight, and power). Ground-stations are needed to move the data up/down, but those have recently become a commodity too. Still, they're not free. (see: https://aws.amazon.com/ground-station)
There is also the added latency between earth-based users and space-based datacenters, which may be a deal breaker for some applications.
Another issue I don't see covered are the significant differences between space-based hardware and terrestrial hardware. The space stuff needs to be radiation tolerant, and that usually makes it a lot slower and a lot more expensive than the terrestrial stuff, all other things being equal.
In the end, space-based datacenters are highly impractical even if you assume that Starship can put anything into orbit very cheaply.
Seems like according to this analysis it all hinges on launch cost and satellite cost. This site's default for Starship launch cost is $500/kg, but SpaceX is targeting much lower than that, more like $100/kg and eventually optimistically $10/kg (the slider doesn't even go that low). At $100/kg (and assuming all the other assumptions made on the site hold) then you break even on cost vs. terrestrial if you can make the satellites for $7/watt (excluding GPUs, as the whole analysis does).
They don't. The expectation the cloud develops in people is that magic computers just appear. They're living at a virtualized layer where all the nitty gritty of real machines going down and needing to be serviced all the time is handled by unseen minions (sorry SREs and DC staff) and cluster management and provisioning software.
The reality is that datacenters in space is mind-boggling stupid, just from the infeasibility of maintenance alone.
First you have to pay energy to get to LEO
A Starship Launch costs[0] 51.75 TJ of energy in terms of its methane fuel.
It will be able to take a payload of 150 tonnes or 331,000 pounds[1].
How many computers is that?
One online estimate says a computer weights 80 lbs or 35 kg.
So 150000 kg / 35 kg/computer = approximately 4285 computers that we can launch into orbit per Starship.
51.75TJ / 4285 computers = approximately 12.08 GJ per computer to place it in orbit.
Let's say each computer is a H200 and consumes 700 watts continuously. How long would it need to run in orbit before it used as much energy for computation as it took to launch it?
12.08 GJ / 700 W = 12,080,000,000 J / 700 J/s = approximately 17,257,143 seconds.
Or about 6.5 months to break even on energy.
That sounds pretty good, except my estimate for the weight of each compute unit and associated power system & cooling etc. are probably underestimates by one or two orders of magnitude. In which case you'd be looking at 5 to 50 years to break even on energy, by which time the chips are obsolete and need to be replaced anyway.
[0] https://space.stackexchange.com/questions/66480/how-much-ene... [1] https://en.wikipedia.org/wiki/SpaceX_Starship#Description
So yes, 10-100x extra is probably reasonable.
The one that does not is the physics of the whole thing. I struggle to work out how exactly but being slightly time dilated compared to the ground does not seem like a win, but being able to gather data from opposite sides of the planet slightly faster than cables does seem like a potential win. Most stock exchanges make a significant chunk of their revenues renting out data space, so it seems a possibility.
But either way it seems very niche.
You know what’s easier and cheaper than putting a data center in space? Putting one literally anywhere else other than space.
But then he never answers that fundamental question, and jumps straight to the hardware and power and cost? What problems are orbital data centers trying to solve? What optimizations are they intended to deliver? Are these optimizations beneficial to everyone who uses a data centers, or just operators or users of orbiting satellite constellations?
> But the knock-on effects are why this keeps pulling at people. If you can industrialize power and operations in orbit at meaningful scale, you're not just running GPUs. You're building a new kind of infrastructure that makes it easier for humans to keep spreading out. Compute is just one of the first excuses to pay for the scaffolding.
This seems to be the closest we get to a “Why”, but it doesn’t make much sense. A constellation of 40,000 satellites with GPUs “infrastructure that makes it easier for humans to keep spreading out”? How?
> The target I care about is simple: can you make space-based, commodity compute cost-competitive with the cheapest terrestrial alternative? That's the whole claim. … Can you deliver useful watts and reject the waste heat at a price that beats a boring Crusoe-style tilt-wall datacenter tied into a 200–500 MW substation?
Isn’t the answer clearly “No”? The default settings of his model — which I assume he considers optimal — tell us that power for orbital data enters will cost 3.5X terrestrial ones. And that only SpaceX has the vertical integration to do even attempt to do this. So again, where is the competitive advantage?
Also, I don’t understand why he’s including satellite construction and launch costs for a 40,000 satellite constellations in his analysis, if he’s assuming SpaceX as he claims. Wouldn’t SpaceX simply implement these compute capabilities in the next gen of Starlink, so which would reduce costs significantly.
> It might not be rational. But it might be physically possible.
But isn’t that precisely what everyone has been saying? I don’t think the question has been whether orbital data centers are possible, it’s been whether they are rational. And that centers foremost h the unanswered question, Why is this a good idea?
"Datacenters in space" make for a catchy narrative and an interesting demo, but the math simply doesn't work.
When considering factors like launch cost, maintenance complexity, and the cost of high-bandwidth communications (latency included), there is no realistic set of economic and engineering assumptions under which orbiting datacenters become cost-competitive with simply building conventional nuclear-powered (or renewable energy-powered) datacenters on the ground.
In fact we're off by 50-100x. Dramatic launch cost reductions still won't make it work. And of course if you invest a lot in specific lines of tech to make it work you then have to consider that the same can also be invested in better ground-based nuclear, bringing the cost of power down for everyone.
man who quotes big number - often made a fool
I do wonder, at what factor of orbital to terrestrial cost factor it becomes worthwhile.
The greater the terrestrial lead time, red tape, permitting, regulations on Earth, the higher the orbital-to-terrestrial factor that's acceptable.
A lights-out automated production line pumping out GPU satellites into a daily Starship launch feels "cleaner" from an end-to-end automation perspective vs years long land acquisition, planning and environment approvals, construction.
More expensive, for sure, but feels way more copy-paste the factory, "linearly scalable" than physical construction.
You can set up plant manufacturing chips in shipping containers and sending them to wherever energy/land is cheapest and regulation most suitable, without having to seek the FCCs approval to get launch approved and your data back...
It's great that this site drills down even further to demonstrate that there is absolutely no point at which the launch costs ever make this economical or viable, so I really don't understand what people are doing.
Especially because this site was harping for years about the cost of launches and putting things in to orbit, the whole reason why SpaceX got started and has grown as it has. As soon as that became an inconvenient number, we now just make things up (Just pretend that launch costs are 10% of what they actually are to get people to invest?).
The $5M is a marginal cost-target for fully reusable Starship.
I think datacentres in space are predicated on Starship bringing launch costs down. Way down.
What are the regulatory/legal gains? Lack of jurisdiction means open slather?
What are the national security gains? Redundancy and resiliency by each satellite being a "micro-compute" connected by high speed laser links? So more resilient to attack?
Why do it at all?
If data is downloaded illegally from space, stored in space and model trained on it... it will be a mess juridically if someone complain.
Same for model inference, it will be hard for a government to put controls on the model output.
It doesn't make sense right now, and won't for at least 5-10 years.
By which time, this current round of hype will have burned up ~$1T if it doesn't fall apart from the current internal contradictions and lack of market/customers/uses.
We're still on the uphill ride of the Gartner hype cycle, not even at the "Peak of Inflated Expectations" yet.
The numbers don't quite work out in favor of orbital datacenters at the current values. But we can tell from analyses like this what has to change to get there.
These numbers are just random bullsh*t numbers.
And what problems do orbital datacenters solve? They still need uplink, so not libertarian we can do what we want, you have no jurisdiction here thing.
This is just a sci-fi idea that is theoretically possible and is riding the ai bubble for users and investors that don’t know better.
The proponents of orbital wunderbars may have different calculations and there's only one way to resolve the differences - make them pay for their space-centers themselves, making sure no public money is spent on the project which is also required to carry zero default risk and pay regular taxes without the right to claim deductions or write-offs for any losses. All this is necessary to avoid the usual corporate tax games.
I can sketch a contract to that end in like 10 minutes. Everything else is a waste of time.
It is much easier to blow things up on land than in space, and the 'negative externalities' simpler to make assumptions about.
The value of this to the people who would be in charge of this "compute" and "storage" is likely much larger than the difference in energy cost.
Putting data centers under water makes way way more sense than into space.
You need permits underwater. You don’t in space.
You've actually got more option to jurisdiction-shop with underwater data, but I'm not convinced that's the major issue with building datacentres anyway.
Ultimately there are latency and minimise data-transfer arguments for doing certain types of data processing on local machines in space, but the generalised compute and model-training argument only works if the unit economics stack up as sufficiently good to cover the risk and R&D, and they're not obviously favourable compared with cold place on earth with clear skies and access to cold water even assuming launch costs become minimal. (It's slightly amusing to see how much some advocates of that other controversial futurist vision of spaced-based solar power - whose chances of success equally depend on low launch costs - viscerally hate the latest wave of datacentres-in-space hype...)
(I agree right now it probably makes sense, but decades and centuries away we probably don't want to warm up earth anymore. If anything space datacenters could provide shade for earth lol.)
It then occurred to me that they (all major AI companies) know all of these facts but still pushing for it so there must be another reason. Then I recalled the offhand statement from the openAI lady about govt backstop for infra, which was strongly opposed by public and AI czar. this might be be a backdoor way of injecting that backstop capital in terms of subsidies now for results in 5 years or so. and needless to say after pilot programs those will fail spectacularly.
> For ML accelerators to be effective in space, they must withstand the environment of low-Earth orbit. We tested Trillium, Google’s v6e Cloud TPU, in a 67MeV proton beam to test for impact from total ionizing dose (TID) and single event effects (SEEs). > > The results were promising. While the High Bandwidth Memory (HBM) subsystems were the most sensitive component, they only began showing irregularities after a cumulative dose of 2 krad(Si) — nearly three times the expected (shielded) five year mission dose of 750 rad(Si). No hard failures were attributable to TID up to the maximum tested dose of 15 krad(Si) on a single chip, indicating that Trillium TPUs are surprisingly radiation-hard for space applications.
Somehow I don't think those are the only options. AFAIK Starlink is using a lot of non-rad-hard silicon already.
The unit economics of orbital GPUs suggest that we'll need to run them for much longer than that. This is actually one of the few good points of orbital data centers, normally older hardware is cycled out because it's not economic to run anymore due to power efficiency improvements, but if your power is "free" and you've already got sufficient solar power onboard for the compute, you can just keep running old compute as long as you can keep the satellite up there.
Random errors will occur you just need to be checking fast enough to fix and update that bad bit flip.
I am sure there's all sorts of fun algorithms in this space but I am under the impression there is SOME tax to doing this. What is the tax? Is it 10% ir 60% I have no idea would love to know!
If you go out to MEO then suddenly you're outside that protective magnetic shield and you have to deal with charged particles smashing into you and you want a large mass of water or wax shielding if you don't have radiation tolerant electronics.
SSO, a low earth orbit whose plane is perpendicular to the direction of the sun so it gets constant sunlight, is harsher than normal LEO orbits because it passes over the poles where the protection from the Earth's magnetic field is weakest, but it's still a lot better than higher orbits. This is probably where you want a datacenter to get constant sunlight and as much protection as possible.
Besides, that's even more mass to be lofted. Pushing the economics further into the ludicrous end.
I think “won’t”. I could be wrong of course, but I imagine efforts to put servers into orbit will die before anything is launched. It’s just a bad idea. Maybe a few grifters will make bank taking suckers’ money before it becomes common knowledge that this is stupid, but I will be genuinely surprised if real servers with GPUs are launched.
I don’t mean to be facetious here. But saying “will” is treating it as inevitable that this will happen, which is how the grifters win.
Silently wrong results are very fashionable these days, you know. Deterministic results are very 2010s.
The fundamental question is “is it economically viable”, and the answer from his model is “not really”
> A constellation of 40,000 satellites with GPUs “infrastructure that makes it easier for humans to keep spreading out”?
I think he’s claiming industrializing larger and more economical power generation in space, as well as the means to put it up there, would make it easier to transition to a theoretical space economy
> But isn’t that precisely what everyone has been saying?
From the article, he claims that people handwave the economics, so at least the people he has interacted with haven’t been saying that.
We don't use them on earth because we expect humans to be near computers and keeping anything extremely hot is a waste of energy.
But an autonomous space data center has no reason to be kept even remotely human habitable.
You can't just scale current silicon nodes to some other substrate.
Even if you could, there's a huge difference between managing the temperature of a single transistor, managing temps on a wafer, and managing temps in a block of servers running close to the melting point of copper.
Unless you have a plan to change the laws of physics, space will always be a good insulator compared to what we have here on Earth.
No need to rewrite anything. Radiators are 30% heavier per watt than solar panels. This is far from impossible.
So maybe if we had such PV, we could make huge gossamer-thin arrays that don't have much mass, then use the power from these arrays to pump waste heat up to higher temperature so the radiators could be smaller.
The enabling technology here would be those very low mass PV arrays. These would also be very useful for solar-electric spacecraft, driving ion or plasma engines.
Could the compute be distributed instead? Instead of gathering all the power into a central location to power the GPUs there, stick the GPUs on the back of the solar panels as modules? That way even if you need active fluid exchanger it doesn’t have to span kilometers just meters.
I guess that would increase the cost of networking between the modules. Not sure if that would be prohibitive or not.
3491 V1 sats × 22.68 m² = 79176 m²
5856 V2-mini sats × 104.96 m² = 614 646 m²
Total: 0.7 km² of PERC Mono cells with 23% efficiency.
At around 313W/m² we get 217MW. But half the orbit it's in shade, so only ~100MW.
The planned Starship-launched V2 constellation (40k V3 sats, 256.94 m²) comes out at 10 km², ~1.5GW.
So it's not like these ideas are "out there".
Distances are not our friend in orbit. Efficiency hyperscales down for many things, as distances and area scale up.
Things that need to hyperscale when you scale distance and area:
• Structural strength.
• Power and means to maneuver, especially for any rotation.
• Risk variance, with components housed together, instead of independently.
• Active heat distribution. Distance is COMPOUNDING insulation. Long shallow heat gradients move heat very slowly. What good does scaling up radiative surface do, if you don't hyperscale heat redistribution?
And you can't hyperscale heat distribution in 2D. It requires 3D mass and volume.
You can't just concatenate satellites and get bigger satellites with comparable characteristics.
Alternatives, such as distributing compute across the radiative surface, suffer relative to regular data centers, from intra-compute latency and bandwidth.
We have a huge near infinite capacity cold sink in orbit. With structural support and position and orientation stabilization for free. Let's use that.
This is all fundamental to the universe. All energy in the universe comes exclusively from systems moving from a low entropy state to a higher entropy state. Energy isn't a static absolute value we can just use. It must be extracted from an energy gradient.
Reminds me of "Those darn cars! Everybody knows that trains and horses are the way to travel."
I don't get this "inevitable" conclusion. What is even a purpose of the space datacenter in the first place? What would justify paying an order of magnitude more than conventional competitors? Especially if the server in question in question is a dumb number cruncher like a stack of GPUs? I may understand putting some black NSA data up there or drug cartel accounting backup, but to multiply some LLM numbers you really have zero need of extraterritorial lawless DC. There is no business incentive for that.
Btw The cute one-line slam doesn't really belong here. It's an empty comment, adds zero to the conversation, contributes nothing to the reader. It only makes a twelve year old feel a brief burst of endorphins. Please refrain.
See here for all the great ways of getting rid of thermal energy in space: https://www.nasa.gov/smallsat-institute/sst-soa/thermal-cont...
Exploring a space-based, scalable AI infrastructure system design - https://research.google/blog/exploring-a-space-based-scalabl... - https://news.ycombinator.com/item?id=45813267 (Nov 4 2025, 44 points, 73 comments)
> Project Suncatcher is a moonshot exploring a new frontier: equipping solar-powered satellite constellations with TPUs and free-space optical links to one day scale machine learning compute in space.
To illustrate the point with a concrete example. You can heat something with the thermal transfer rate of aerogel to an absurdly high temperature and it will still be safe to pick up with your bare hand. Physics says it has a temperature but our intuition says something is wrong with the physics.
Yes I'm making that argument. Because it's true. The temperature of what particles do exist, 500km above the earth, is more likely to be in the thousands of degrees farenheit than below zero farenheit.
The discussion being had, if you read comments above your original, is that it's widely thought that "space is cold" and therefore it's good for cooling.
You're right that heat capacity means that the temperature of space is not relevant to its ability to cool a datacenter. You're wrong that making that argument is a good way to get people to actually change their mind.
Instead, attack the idea at its foundation. Space is not cold, not in the places where the data centers would be. It's much easier to get someone to understand "the temperature at 500km where the auroras are is very hot" than "blah blah heat capacity".
Now you see the point!
So now we have arrived to a revised solution: a puny 8RU server at 130 kg, requires 100sqm and 1000 kg of solar panels, then 50-75 sqm of the heat radiators at 1000-1500 kg, then 100-200 kg of batteries and then the housing for all that stuff plus station keeping engines and propellant, motors to rotate all panels, pumps, etc. I guess at least 500kg is needed, maybe a bit less.
So now we have a 3 ton satellite, which costs to launch around 10 million dollars at an optimistic 3000/kg on F9. And that's not counting cost to manufacture the satellite and the server own cost.
I think the proposal is quite absurd with modern tech and costs.
I bet you a million dollars cash that you would not be able to reach them.
I'd be interested to know what the average lifespan or failure rate of Starlink has been. That's good that some are still up there 6+ years later, but I know many aren't. I'm not sure how many of those ran out of fuel, had hardware failures, or were simply obsolete, but an AFR would be interesting to see.
https://news.ycombinator.com/item?id=16527007 ("First firing of air-breathing electric thruster (esa.int)" (2018))
FCC is easier to deal with than multiple layers of environmental, planning, power, and water concerns at the local, state and federal levels.
> they're not obviously favourable compared with cold place on earth with clear skies and access to cold water
There are fewer of those places that can be developed than there is space. The bottleneck to space is launch. The bottleneck on the ground is power.
I don’t think anyone thinks the math works right now. But as OP showed, it’s surprisingly proximate in a way SBSP is not.
If you get fed up of multiple layers of concerns and US specific bureaucracy, you simply move to a different country where a single authority is desperate to not only remove hurdles but might even give subsidies to someone that wants to employ lots of people to put up solar panels and give them a bit of surplus power and hot water. Chips and solar panels fit as easily in shipping containers as they do in spacecraft. The FCC actually has to handle the concerns of entities more concerned by the environmental impact of your megaconstellation because it's a 1km^2 wide missile travelling at 17,500 mph which much of the rest of the space industry is expected to expend propellant to evade where orbits intersect, which is a bit more concerning than 5km^2 of slightly less green fields and some question marks about water abstraction, and there aren't other authorities you can turn to. (Space is underregulated in terms of not having any practical traffic management beyond launch and spectrum licensing, but that's more risk rather than dream libertarian business opportunity; the FCC can still kibosh your project, you just won't get anyone clearing debris out your way)
Technically there is more space in space than Earth, but once you start factoring that convenient orbits for earth data transfer involve carving a high speed path which intersects with other spacecraft also moving at high speed and not all with as much control as they'd like it starts to look a lot less capacious. The Earth not about to run out of coastal regions with unbuilt land any time soon.
(SBSP has its own similar issues, of course)
So no, you cannot increase too much the height of the pyramid, there will be some optimum value at which the pyramid will certainly not be sharp. The optimum height will depend on how much of the pyramid is solid and which is the heat conductance of the material. Circulating liquid through the pyramid will also have limited benefits, as the power required for that will generate additional heat that must be dissipated.
A practical radiation panel will be covered with cones or some other such shapes in order to increase its radiating surface, but the ratio in which the surface can be increased in comparison with a flat panel is limited.
its CPU/GPU clusters, so we don't have 0 control on where to locate what heat generators, but even if we had 0 control over it, the shape and height of the pyramid does not preclude heat pipes (not solid bars of metal, but having a hot side where latent heat of a gas condensing to a liquid on the cold side and then evaporating on the hot side).
heat pipes have enormous thermal conductivities
Problem is with solar panels themselves. When you get 1.3kW of energy per square meter and use 325w of that for electricity (25% efficiency) that means you have to get rid of almost 1kW of energy for each meter of your panel. You can do it radiatively with back surface of panels, but your panels might reach equilibrium at over 120°C, which means they stop actually producing energy. If you want to do it purely radiatively, you would need to increase temperature of some surface pointing away from sun to much more than 120°C and pump heat from your panels with some heatpump.
Nevertheless, the problem described by you remains, the panels must dissipate an amount of heat at least equal with the amount of useful power that is generated. Therefore they cannot have other heat radiators on their backside, except those for their own heat.
The physics is quite simple and you can definitely make it work out. The Stefan Boltzman law works in your favor the higher you can push your temperatures.
If anything a orbital datacenter could be a slightly easier case. Ideally it will be in an orbit which always sees the sun. Most other satellites need to be in the earth shadow from time to time making heaters as well radiators necessary.
I suppose one could get some sub part of the whole satellite to a higher temperature so as to radiate heat efficiently, but that would itself take power, the power required to concentrate heat which naturally/thermodynamically prefers to stay spread out. How much power does that take? I have no idea.
(293^4 - 283^4) = 9.55e8
(363^4 - 283^4) = 1.09e10
So about 10x
I have no problem with your other numbers which I left out as I was just making a very rough estimate.
I'm assuming the radiators are shaded from that flux by the rest of the satellite, for efficiency reasons, so we don't need to account for solar flux directly heating up the radiators themselves and reducing their efficiency.
In the shade, the radiators emission is relative to the background temp of empty space, which is only 2.7 K[0]. I did neglect to account for that temperature, that's true, but it should be negligible in its effects (for our rough estimate purposes).
[0] https://sciencenotes.org/how-cold-is-space-what-is-its-tempe...
the first booster landing after delivering a payload to orbit was quite something and made a serious stir in the industry.
But since there are so few such molecules in any cubic meter, there isn't much energy in them. So if you put an object in such a rarefied atmosphere. It wouldn't get heated up by it despite such a gas formally having such a temperature.
The gas would be cooled down upon contact with the body and the body would be heated up by a negligible amount
Accepting everything they then do, forever, even when it's obviously nonsense, is what gets you called a "huge batshit crazy fanbase of boot lickers".
This "idea" is great party conversation. It's probably doing a great job of shoving around the Overton window, too (perhaps the real goal here?). It's, uh, not realistic, and anyone who is seriously "all in" on it (you're allowed to consider it and to dream, that's not the same as being all in) is not worth taking seriously no matter how much of the oxygen in the room they're using up.
You not only need absolute huge radiators for a space data centre, you need an active cooling/pumping system to make sure the heat is evenly distributed across them.
I'm fairly sure no one has built a kilometer-sized fridge radiator before, especially not in space.
You can't just stick some big metal fins on a box and call it a day.
If we run the radiators at 80C (a reasonable temp for silicon), that's about 350K, assuming the outside is 0K which makes the radiator be able to radiate away about 1500W, so roughly double.
Depending on what percentage of time we spend in sunlight (depends on orbit, but the number's between 50%-100%, with a 66% a good estimate for LEO), we can reduce the radiator surface area by that amount.
So a LEO satellite in a decaying orbit (designed to crash back onto the Earth after 3 years, or one GPU generation) could work technically with 33% of the solar panel area dedicated to cooling.
Realistically, I'd say solar panels are so cheap, that it'd make more sense to create a huge solar park in Africa and accept the much lower efficiency (33% of LEO assuming 8 hours of sunlight, with a 66% efficiency of LEO), as the rest of the infrastructure is insanely more trivial.
But it's fun to think about these things.
Put another way, 2 sq m intercepts 2600 w of solar power but only radiates ~1700 w at 350 k, which means it needs to be run at a higher temperature of nearly 125 celsius to achieve equilibrium.
It receives around 2.5kW[0] of energy (in orbit), of which it converts 500W to electric energy, some small amount is reflected and the rest ends up as heat, so use 1kW/m^2 as your input value.
> If we run the radiators at 80C (a reasonable temp for silicon), that's about 350K, assuming the outside is 0K which makes the radiator be able to radiate away about 1500W, so roughly double.
1500W for 2m^2 is less than 2000kW, so your panel will heat up.
[0] https://www.sciencedirect.com/topics/engineering/solar-radia...
You need enough radiators for peak capacity, not just for the average. It's analogous to how you can't put a smaller heat sink on your home PC just because you only run it 66% of the time.
