Is this article intended as rage bait? Posit a patently unnecessary and ruinously expensive idea. Then offer zero critique of that proposal. I expect more from ars than this.
The arguments that the companies make themselves on their own websites are ridiculous. There is no data center land crisis, nor energy crisis that is best solved by putting mass compute into orbit. Leave aside the dubious financials. Wtaf
Let's stop and consider your 144 kW per rack of electrical power. If we're in sun-synchronous orbit at the terminus, we can expose our solar panels 100% of the time, but they're only going to be about 30% efficient at converting solar power into electricity.
[...]
So please, feel free to crap on the idea of datacenters in space for any number of compute or financial reasons. But let's retire the idea that cooling in space is a technology bottleneck.
Stock in a privately singly held company.Someone call me when any of these rich idiots have any idea how they are going to cool megawatts of computers in the vacuum of space.
Lines like these are about stock price manipulation.
This thorough, factual comment is very welcome. Contrast with people here complaining about the insane space data center gold rush while at the same time skim-reading the content and comments they're replying to in their own desperate rush to get their comments onto the first page.
I see your comment got more downvotes than upvotes, but no counterarguments. Therefore all the negative vote count indicates is the degree to which the downvoters lost the argument.
This line really should not be so matter of fact. It is an extremely speculative statement. It's not clear how this would improve, let alone enable, AI. It also doesn't really say what kind of AI it would instantiate, as current LLM's certainly don't need to be in space. It's not even clear in-space processing is that good of an idea in general. Indeed, there's a lot to argue against it.
OK so if the ground stations are not in the US, what does the FCC care then?So the alleged data center in space uses a really long USB cable to communicate with a single point on the ground? Or do smoke signals work in space?
Is anybody making the argument that cooling is physically impossible or are you attacking a straw man? The cooling loop you glossed over makes the server rack the largest non-human-carrying payload ever launched into space (unclassified, at least). How is that not a bottleneck to wanting to launch thousands of them into space? These guys will essentially be in business launching cooling equipment into space... With a little bit of data center attached.Can we please, please, please, retire concerns about cooling in space? For all the problems the idea of datacenters on-orbit have, cooling is not one of them. Or, at least, the math actually closes. This is at least the third time I've walked through this exercise, but perhaps this time it will stick.
Let's stop and consider your 144 kW per rack of electrical power. If we're in sun-synchronous orbit at the terminus, we can expose our solar panels 100% of the time, but they're only going to be about 30% efficient at converting solar power into electricity.
For every square meter of solar panel pointed perfectly perpendicular to the sun, there's 1361 W/m^2 of solar power of which 400 W/m^2 will turn into useful electrical power. That means that for every 144 kW rack you describe above, you need to have 352 m^2 of solar panel to power it. That's a square 18.7 m on a side. Are you starting to see why the cooling issue closes?
The important thing to realize is that for all the massive real estate I'm going to have to allow for solar panels also provides a massive amount of real estate for radiators. And since the solar panels are always pointed at the sun, the back side is always pointed at empty space.
At this point, we have to make assumptions about surface temperatures, etc. but there are a few points to realize. If the radiators and the solar panels are the same temperature (given that the former is on the back side of the latter), then we have to consider that both sides of the solar panel / radiator are actually acting as radiators. Sure, in the direction of the sun the solar panels are certainly receiving a net amount of energy. However, for most of the hemisphere where a photon can try to emit, it's empty space too. If you're going to use heat pumps or the like to increase the radiator temperature, then you can mostly ignore the radiation from the solar panel side and have to consider just the area of the radiator (especially since you'll need more power to drive the heat pumps and therefore more solar panels).
So, for grins, let's consider a double-sided system (front and back) that has to reject (1361 W/m^2) / 2 . Use your favorite online blackbody calculator to determine the surface temperature of an ideal surface that can reject the amount of power that the sun puts on the panels. In the end, you'll find that you need 331 K or a 58 deg. C skin temperature. That's hot to touch, but certainly not too hot to run integrated chips or solar panels.
If we distribute your 144 kW of compute in that 352 m^2 area, there won't even need to be hot spots. If you're being smart and having a separable compute node that connects to cooling and power, you'll probably want a liquid loop of some sort to draw the heat away. You'll probably need 10 deg. C higher temperatures on your GPUs than the final 58 deg. C mark, but that's still very reasonable.
So please, feel free to crap on the idea of datacenters in space for any number of compute or financial reasons. But let's retire the idea that cooling in space is a technology bottleneck.
While it is indeed a "factual comment", it also has little to do with the one it was replying to nor the comment that that comment was replying to.This thorough, factual comment is very welcome. Contrast with people here complaining about the insane space data center gold rush while at the same time skim-reading the content and comments they're replying to in their own desperate rush to get their comments onto the first page.
Unless you can read minds, all down voting means is that people clicked the downvote button. Imagining the motivations of why people downvoted the comment is a waste of time.I see your comment got more downvotes than upvotes, but no counterarguments. Therefore all the negative vote count indicates is the degree to which the downvoters lost the argument.
Hmm, that seems to fall into an economic argument. The last paragraph of my post almost invites that criticism:The ISS EEATCS ammonia-loop system can radiate a maximum 70kW of waste heat. It weighs 14 metric tons, which a quick google suggest will cost around $100 million to launch into orbit. So more than $200 million for a single rack of processors just for the cooling. Now add all the stuff you actually need to do any useful work.
I will indeed crap on the idea of datacenters in space because an impossibly expensive solution that makes zero economic sense isn't going to happen, even if theoretically you could engineer around the cooling problem.
Edit: Shit. I didn't account for a failure, so double everything for redundancy. You're looking at a billion dollars in overheads per rack of capacity, at a time that AI companies are haemorrhaging money. It's a fantasy.
So please, feel free to crap on the idea of datacenters in space for any number of compute or financial reasons. But let's retire the idea that cooling in space is a technology bottleneck.
The post I quoted was the third exchange of a discussion about the possibility of cooling. So yeah, not a strawman.Is anybody making the argument that cooling is physically impossible or are you attacking a straw man? The cooling loop you glossed over makes the server rack the largest non-human-carrying payload ever launched into space (unclassified, at least). How is that not a bottleneck to wanting to launch thousands of them into space? These guys will essentially be in business launching cooling equipment into space... With a little bit of data center attached.
https://meincmagazine.com/space/2026/...lation-too/?comments=1&post=44319961#commentsIs anybody making the argument that cooling is physically impossible or are you attacking a straw man? The cooling loop you glossed over makes the server rack the largest non-human-carrying payload ever launched into space (unclassified, at least). How is that not a bottleneck to wanting to launch thousands of them into space? These guys will essentially be in business launching cooling equipment into space... With a little bit of data center attached.
I will add that the 2D approximation is the limit for cooling. Once you have a massive structure with solar cells on one side and radiators on the other you have reached the minimal limit of cooling. Any sort of 3D structure (such as arrays of satellites flying in clusters) will have better cooling than my numbers. As such, my approximation is the most conservative back-of-the-envelope calculation one can make.https://meincmagazine.com/space/2026/...lation-too/?comments=1&post=44319961#comments
So, you decided to crap in a comment before reading the thread of comments back to see if your comment was right?
Commenters have been saying that you can't cool it. Not that it's too expensive, but that the engineering doesn't adds up.
When Musk talks about this, you can assume that he is ignoring the engineers and accountants in SpaceX saying that this is too expensive because he wants to prop up SpaceX value for the IPO.
But as far as we know, BO isn't accepting outside investors, so if Bezos is also talking about this, maybe the engineers/accountants found out that if they manage to hit certain numbers then the system works.
Wickwick numbers were about putting a rack per sat, maybe that's not needed. If you are consuming less than 30kW you don't even need a separate radiator if your sat is the same size as a Starlink V2.
So now cost are down. Now you need to know some internals about the company running public LLM models. How much compute are they using while training vs how much compute are they using while doing inference. How much power does a prompt uses in their different models? How long does it takes from query to response? Etc.
With that set of information you can conclude if you are going to make money with this or not.
Also, unlike Starlink, you don't need to populate that much of your shells to start making money with the service. If you could use a communication constellation as your communication backbone, you can provide service from the first sat that you launch.
Does it makes economical sense?, I don't know. To me not even building datacenters on Earth makes economical sense for AI given that all of them keep losing money selling their services, so I'm probably not the one to ask about this.
I also don't see
OK so if the ground stations are not in the US, what does the FCC care then?
Hmm, that seems to fall into an economic argument. The last paragraph of my post almost invites that criticism:
Its all a scam to lure in investor money. Data centers rely on low latency and require ongoing upgrades and repairs. How do yo do that in space at a competitive price, in a timely fashion? You don't. All they are doing at that point is cluttering the orbits with soon to be obsolete hardware that costs way more and is. Meanwhile traditional datacenters are kept upgraded for a fraction of the cost. Anyone investing in it will do so chasing the AI in space buzzword but in reality they will be signing up for a rather blatant rug pull.This line really should not be so matter of fact. It is an extremely speculative statement. It's not clear how this would improve, let alone enable, AI. It also doesn't really say what kind of AI it would instantiate, as current LLM's certainly don't need to be in space. It's not even clear in-space processing is that good of an idea in general. Indeed, there's a lot to argue against it.
Commenters have been saying that you can't cool it. Not that it's too expensive, but that the engineering doesn't adds up.
What makes you think the size of the constellation is inherently a problem?You don't have to put entire racks in a single satellite--but then you create other problems. Like needing 100,000+ satellites to do the same compute as a single terrestrial data center (depending on the size of "data center' you want to compare to since they're all different).
I have a link to that exact comment in the comment that you are responding to. It's not about how you are going to pay for the cooling, it's about how they are going to do it.Bullshit. Please link to the comment where someone has claimed that it's impossible as opposed to stupidly expensive. I went back - no such comment exists.
Someone call me when any of these rich idiots have any idea how they are going to cool megawatts of computers in the vacuum of space.
When you have to launch multiple times the photovoltaic and cooling capacity of the ISS to service one rack of GPU's how do you figure that the equivalent of 100,000 of the largest satellite humanity has put into orbit is even remotely possible?What makes you think the size of the constellation is inherently a problem?
Where else on a satellite in sun terminator orbit will have enough shade?There is no need to constrain deployed volume in such a way; just mount the radiator arrays somewhere else.
I have a link to that exact comment in the comment that you are responding to. It's not about how you are going to pay for the cooling, it's about how they are going to do it.
Not that's it's impossible, but how are they going to do it? It's a fair question, given the scale of the problem.how they are going to cool megawatts of computers in the vacuum of space.
Either from surface radiation of the sat itself, or separate radiators if the sat uses too much power.
Plenty of comments have said that if you had read them.Is anybody making the argument that cooling is physically impossible or are you attacking a straw man?
So what?The cooling loop you glossed over makes the server rack the largest non-human-carrying payload ever launched into space (unclassified, at least).
Starship and New Glenn 9x4 are going to be capable of huge payloads at low cost.How is that not a bottleneck to wanting to launch thousands of them into space?
How is that different from AST SpaceMobile, a company that sends IP huge antennas with a tiny bit of radio attached? And why does it matter?These guys will essentially be in business launching cooling equipment into space... With a little bit of data center attached.
The ISS example is about cost, not how. It claims what it says in the text that I pasted, how are they going to do it. The how is already answered, how much it's going to cost, it's another different question, that wickwick says that it's the true question that BO and SpaceX need to answer. Not the how.I saw it - it doesn't say what you claim.
Not that's it's impossible, but how are they going to do it? It's a fair question, given the scale of the problem.
Already addressed above using the example of the ISS. Try reading.
Why do you think they will be using space based data centers for training. They will want to run models trained on Earth where the data and bandwidth is located, and just run them in the space data centers.No, much of the hardware literally dies within 5 years. The mean time between failures for an Nvidia GPU used for AI training is a couple years. Less if it's highly utilized.
Plenty of comments have said that if you had read them.
The ISS example is about cost, not how. It claims what it says in the text that I pasted, how are they going to do it. The how is already answered, how much it's going to cost, it's another different question, that wickwick says that it's the true question that BO and SpaceX need to answer. Not the how.
How much, and how, are not the same question.
Operating commercially viable and can't be done aren't the same thing. SLS isn't commercially viable, it's launching. Vulcan isn't commercially viable (ULA is going to end losing money on it), they are launching. Starliner isn't commercially viable, they are still trying to launch.Bullshit. If the "how" makes it impossible to operate commercially then the answer may as well be "can't be done".
FFS: if the answer is "spend a billion dollars to cool a single racks worth of GPUs" then you do not have a viable solution to putting datacenters into orbit. Stop smoking crack.
Operating commercially viable and can't be done aren't the same thing.
Also the 144kW per sat isn't a known requirement for the constellation. So it shouldn't be used to argue about the economics.
So, maybe a 40kW sat twice as big can do the same, I don't know, but if you could, now you don't need to launch 2 to 4 ISS sized radiators per sat. There is probably a size under 144kW in which you only need to launch 1 ISS sized radiator per sat and get enough work done in the sat that it can do actual work.
This would solve the water problem for data centers. How does that suck?The future sucks.
Don’t have to find water to cool everything. Don’t have to pay for the real estate.What's the play here? I don't understand what the benefit of a data center in the sky is over a data center in Stuttgart, Arkansas.
Or is this just a ploy for investor dollars and to justify Bezos' space ambitions?
There is no water problem for data centers. If they had to, they would just recycle the water but it is more economical not to at this point.This would solve the water problem for data centers. How does that suck?
What makes you think the size of the constellation is inherently a problem?
Since you asked...Where else on a satellite in sun terminator orbit will have enough shade?
If it's an economic argument, why harp on the radiators? They're going to be one of the cheaper things to send up - certainly cheaper than the solar panels. Cheaper than the rest of the structural elements or the station-keeping, etc.Bullshit. If the "how" makes it impossible to operate commercially then the answer may as well be "can't be done".
FFS: if the answer is "spend a billion dollars to cool a single racks worth of GPUs" then you do not have a viable solution to putting datacenters into orbit. Stop smoking crack.
All questions of feasibility are both economic and technical questions. The two are inextricable. It’s not worth discussing one or the other, as if the people proposing these systems can afford to ignore either practicability or costs.If it's an economic argument, why harp on the radiators? They're going to be one of the cheaper things to send up - certainly cheaper than the solar panels. Cheaper than the rest of the structural elements or the station-keeping, etc.
The thermal issue is a dead one. In numerous threads it's the first technical (not economic) objection and it's indicative of someone that's doing engineering by association rather than by numbers.
I would argue it is worth discussing where the technical challenge actually lie, because it lends legitimacy to argument. It's important to understand the underlying points in why space-based data centers are a dumb idea in the first place. When someone says "this is a non-starter because of the inherent thermodynamics of cooling a data center only through radiative transfer, modulo some stupidly large surface area" ignores the fact that the power generated by a typical data center first requires massive amounts of solar panels. And if you've solved that problem, then you've also solved the surface area requirements needed for your radiators. If I'm understanding the logic correctly, it should be conceivable for a space data center that is powered solely by solar panels to radiate away the heat that it generates (ie., you can't generate more heat than you've already collected from the sun, which means technically you can radiate that away).All questions of feasibility are both economic and technical questions. The two are inextricable. It’s not worth discussing one or the other, as if the people proposing these systems can afford to ignore either practicability or costs.
That's a reasonable summary.I would argue it is worth discussing where the technical challenge actually lie, because it lends legitimacy to argument. It's important to understand the underlying points in why space-based data centers are a dumb idea in the first place. When someone says "this is a non-starter because of the inherent thermodynamics of cooling a data center only through radiative transfer, modulo some stupidly large surface area" ignores the fact that the power generated by a typical data center first requires massive amounts of solar panels. And if you've solved that problem, then you've also solved the surface area requirements needed for your radiators. If I'm understanding the logic correctly, it should be conceivable for a space data center that is powered solely by solar panels to radiate away the heat that it generates (ie., you can't generate more heat than you've already collected from the sun, which means technically you can radiate that away).
I feel like people have lost the plot when they're yelling at Wickwick for simply pointing this out (while also suggesting there are a whole slew of other reasons to be critical of this whole endeavor).