I've been saying for a long time that we should consider remote areas for building datacenters for batch processing.
At first I thought the poles (of the planet) might be good. The cooling is basically free. But the energy and internet connectivity would be a problem. At the poles you can really only get solar about three months a year, and even then you need a lot of panels. Most of Antarctica is powered diesel because of this.
So the next thought was space. At the time, launching to space was way too costly for it to ever make sense. But now, with much cheaper launches, space is accessible.
Power seems easily solved. You can get lots of free energy from the sun with some modest panels. But to do that requires an odd orbit where you wouldn't be over the same spot on earth, which could make internet access difficult. Or you can go geostationary over a powerful ground station, but then you'd need some really big batteries for all the time you aren't in the sun.
But cooling is a huge problem. Space is cold, but there is no medium to transfer the heat away from the hot objects. I think this will be the biggest sticking point, unless they came up with an innovative solution.
> As conduction and convection to the environment are not available in space, this means the data center will require radiators capable of radiatively dissipating gigawatts of thermal load. To achieve this, Starcloud is developing a lightweight deployable radiator design with a very large area - by far the largest radiators deployed in space - radiating primarily towards deep space...
They claim they can radiate "633.08 W / m^2". At that rate, they're looking at square kilometers of radiators to dissipate gigawatts of thermal load, perhaps hectares of radiators.
They also claim that they can "dramatically increase" heat dissipation with heat pumps.
So, there you have it: "all you have to do" is deploy a few hectares of radiators in space, combined with heat pumps that can dissipate gigawatts of thermal load with no maintenance at all over a lifetime of decades.
This seems like the sort of "not technically impossible" problem that can attract a large amount of VC funding, as VCs buy lottery tickets that the problem can be solved.
sfink · 1h ago
Or we could build a large vacuum chamber here on Earth and put a data center in it, if the goal is to make cooling as difficult as possible. "My data center is too hot! It's burning me!" "Put it in a giant thermos, then you won't feel it anymore."
> They also claim that they can "dramatically increase" heat dissipation with heat pumps.
Right, great idea. Start with the heat where you don't want it -- in the chip -- and pump it out to where it can't go anywhere. Then you can recirculate the medium back and have slightly older heat that you can mix with the new heat! It'll be a heat party!
It's just like a terrestrial heat pump, where you pump the heat out to where you have a huge environmental sink to transfer the heat to. In space, you have something like a hundred thousand hydrogen atoms per cubic meter to take up the heat. A HUNDRED THOUSAND! That's a bigly number, it must work out. We can always make those atoms go really, really fast!
The whitepaper shows a 4km x 4km solar array, which is 1600 hectares (3200 International Space Stations). Would assume the array they're proposing would be cheaper since its structurally more homogenous, but $480 trillion dollars is a whole lot of money.
mrj · 1h ago
An object of that size in orbit seems like it'd run into problems developing sizable holes due to space junk and whathaveyou. There's probably some maintenance...
hnuser123456 · 1h ago
Obviously use the heat pumps to concentrate the thermal energy up to 2700k, then conduct it along a bunch of tungsten filaments, now it's the world's biggest incandescent lightbulb on top of being the first datacenter in space. Maybe get it up to 4000k for a more modern lighting look. Guess we're gonna assume the dark forest hypothesis is false.
alfiedotwtf · 55m ago
Could they concentrate the energy and beam it down to earth as a source for electricity generation on the ground?
ianhowson · 8m ago
This is the best idea to come out of this whole scheme. Space solar panels are super cheap and efficient? Prove it! Launch them and transmit the energy down.
This is orders of magnitude easier than the original proposal -- and yet still nonsensical.
Invictus0 · 1h ago
I don't get it--are the founders just grifters? How did this startup even make it off the drawing board?
onlyrealcuzzo · 1h ago
Probably because space companies will invest in you to feed their bubble.
You have to find trillions of dollars of future launches to justify current valuations.
erulabs · 1h ago
a 1% chance of making a billion dollars is worth 1 million dollars.
mjcohen · 51m ago
10 million
foobiekr · 1h ago
[flagged]
dang · 1h ago
That crosses into personal attack, which is not allowed on HN, so please don't.
It’s only a grift if they know they can’t solve the cooling issue and they falsify data around their proposed solution and they publicly embarrass their investors a la Theranos.
Outside of that, accepting money and saying “I will simply solve the enormous problem with my idea by solving it” is not only normal, but actively encouraged and rewarded in the VC sphere. Suggesting that that way of operating is anything short of the standard that should be aspired to is actually seen as derisive and offensive on here and can get you labeled as gauche or combative.
jamessinghal · 39m ago
I'd argue that some of the assumptions made in the whitepaper are so egregiously optimistic that they cross the line into grifting, but it's impossible to know the true intentions of the founders.
For one, the cost they ascribe to the space bound solar array being only $2 million for 40 MW is pretty out there.
dijit · 1h ago
> I've been saying for a long time that we should consider remote areas for building datacenters for batch processing.
FWIW there's a reason that Sweden has a bunch of datacenters in the north that are peanuts compared to hosting in Virginia.
They're "poorly" connected (by virtue of being a bit out of the way), but the free cooling and power from renewables make them extremely attractive. There was a time where they were the favourite of crypto-miners for the same reason as they would be attractive to AI training farms.
As for the meat of the paper. Anyone with a passing understanding of space will be quick to point out that:
A) Heat is a problem in space, it's either way-way-way to hot (IE; you're in the path of the Sun) or it's way-way-way too cold (IE; you're out of the sun) and the shift between the two means you need to build for both. You also can't dissipate heat as there's no air to take the heat away.
B) Power is not so abundant and solar panels degrade; a huge amount of satellite building is essentially managing a decline in the capability of hardware. That's part of why there are so many up there.
C) Getting reasonably sized hardware up there is beyond improbable, though I'll grant you that most of the weight in a computer is the cooling components and chassis.
D) Cosmic Rays. No electromagnetic barrier from earth and extremely tight lithographies. I mean... there's a reason NASA is still using CPU's measured in the megahertz range.
vonneumannstan · 2h ago
>But cooling is a huge problem. Space is cold, but there is no medium to transfer the heat away from the hot objects. I think this will be the biggest sticking point, unless they came up with an innovative solution.
Their main tech breakthrough would have to be in this area otherwise the company is worthless imo.
daeken · 1h ago
It's possible to do all of this with current technology. Just... Why? The cost would be exorbitant; even with really clever deployment tech, the launch costs are gonna be dominated by solar panels and radiators.
This is a super cool idea and seems like perfect investor-bait. That's about where it ends.
matt-p · 1h ago
Genuinely most "AI" DCs are spending less than 9KW on cooling for every 100KW of servers. If you were that bothered about getting that to zero, you could literally sink them into the ocean, build a heat network so the town can take the heat for free or use any of a dozen more established and practical ways to do that.
azinman2 · 1h ago
Please don’t suggest heating the ocean! Someone might just go to try to do that. The ocean is already warming too much!
jamessinghal · 37m ago
It's a bit demoralizing how many suggestions in this thread would have significant environmental effects beyond what large scale AI training already has.
matt-p · 28m ago
It's already being done all over the place. It's not particularly damaging compared to the alternatives.
handfuloflight · 1h ago
Perhaps a hedge in case apocalyptic scenarios disable or reduce networks on the ground?
jsheard · 1h ago
Apocalyptic scenarios where terrestrial communication methods going back over a century are no longer feasible, but we can still readily talk to space? And maintain/replace the stuff we have up there?
arp242 · 1h ago
Yes, because in an apocalyptic scenario what we all will be clamouring will be space data centres training AI and mining bitcoin.
thrance · 1h ago
I don't think they can bend the laws of physics though. Vacuum means the only way to dissipate heat is through thermal radiation, hence the huge infrared radiators.
pauletienney · 2h ago
I have no clue about space technology but many comments point the difficulty to cool anything in space. If Starcloud had an innovative solution to this problem, why on Earth (sic) focus on data centers when they could help the entire space industry? It does not smell good.
ziofill · 1h ago
Perhaps I'm missing something, but if the only energy they get is coming from the sun, then they only need to dissipate that same amount of heat (minus whatever energy was needed for beaming data down to Earth).
ceejayoz · 21m ago
The wrinkle is that taking it in is much, much easier than radiating it back into space.
bongodongobob · 1h ago
What you're missing is that you'd have a huge solar array that powers something much smaller, so that energy gets concentrated into a small area.
gbear605 · 1h ago
That’s not how it works. With conservation of energy, all the energy coming in to power the computers has to be emitted somehow. Powering computers doesn’t get rid of the energy, it just makes it unusable and converts it into heat.
vasco · 1h ago
> But to do that requires an odd orbit where you wouldn't be over the same spot on earth, which could make internet access difficult
Routing through starlink should have direct LoS at all times.
jsheard · 1h ago
Whether Starlink can keep up with the bandwidth demands of orbital datacenters is another question though.
(probably not)
38 · 1h ago
> At first I thought the poles (of the planet) might be good. The cooling is basically free.
Yes, let's go ahead and finish melting the ice caps, great idea
echoangle · 1h ago
I’m still not sure how people can believe this, this makes zero sense to me.
There is no easy passive cooling in space, getting rid of heat is a major problem. And you need more redundancy because the radiation will crash your computers. And launch is very expensive of course.
And the whole presentation is completely ludicrous. Look at table 1 in the linked PDF and tell me you’re serious. There is no additional cost when sending a datacenter to space except launch cost and shielding? Building a server farm on earth is the same price as building a satellite you can launch on a rocket as long as you use the same computers?
slashdev · 1h ago
I agree, this is makes no sense at all.
Can I take the other side of this investment? Like an angel funding round, but selling short?
lionkor · 2m ago
Wait, I just realized - you do this by pitching your own shit idea. That's the other side of the investment!
debatem1 · 57m ago
If you figure out how to do this I will invest in your fund.
rjbwork · 20m ago
Gotta figure out how to sell these guys shovels
rogerrogerr · 13m ago
If someone figured out how to provide a way to bet against startups… could we say they’re selling grave shovels?
echelon · 9m ago
A futures market for startup equity where you can short sell would be wild.
Otherwise when the big firms go public (A16Z etc.), options trading on their stock.
jsheard · 42m ago
I think the other side of this is just buying Amazon stock based on the daring prediction that big grey buildings full of servers aren't going anywhere.
echoangle · 26m ago
That still leaves you with the risk that Amazon is replaced by other earth-based data center operators.
lionkor · 3m ago
The SSI fund - shorting shit ideas since 2025.
CobrastanJorji · 19m ago
You know, that's a fascinating idea. Most startups fail, a few modestly succeed, but the unicorns are so profitable that they mostly make up for the rest. That reminds me of two fields: insurance and gambling.
Venture Capitalists are already like reverse insurance companies. They cover lots of people in the hopes that one of them will hit a rare event and it'll pay for the others.
Buying shares of a single startup is sort of the equivalent of betting on a specific horse to win a race. But what's the equivalent of lay betting (betting that a specific horse will NOT win)? Shorting? But you can't short a private company.
But wait, venture capitalists are already betting that their startups will make money. What if they were willing to double down a bit and accept lay bets? Say there was a kind of specialized short agreement that let you say "here is $x, if in N years company Y has less than $z profit/revenue, I get K*$x. Otherwise, VC gets to keep my $x." You could sell it to VCs as a way to do options trading on their own startup investments, plus it'd be a good way to get the wisdom of the crowds or whatever.
dfltr · 42m ago
There should be a whole checklist of "Things that were still a hard problem in The Expanse" that any space-related startup has to answer.
esperent · 1h ago
> There is no easy passive cooling in space, getting rid of heat is a major problem
Nonetheless getting rid of heat (by radiation) is possible, otherwise people would be roasted inside the ISS.
I'm sure all of these companies are advertising "ChatGPT in Space!" because that's what will generate hype and money, but what they'll actually be planning is very small edge data centers whose job is to reduce latency.
Whether that makes financial sense, I have no idea. But I am sure it's at least physically possible for a small enough data center.
echoangle · 42m ago
Of course it’s possible. But they are acting like having the datacenter in space is actually an advantage over earth because space is cold.
That’s like saying „if you’re thirsty on a ship, getting thrown into the sea is actually really nice because you will be around a lot of water.“.
Physically, you could do it, but it won’t be simpler or cheaper than on earth. Except for constant solar availability, there are only downsides with this.
matt-p · 24m ago
Reduce latency for what? I can't think of how, unless of course you ran a laser down to starlink or some other completely impractical plan.
lxgr · 42m ago
> very small edge data centers whose job is to reduce latency
Reduce latency to where?
trebligdivad · 28m ago
Could this be a military image processing use? - imagining you're scooping up earth observation in real time, if you AI analysed it locally and then just sent a 'Missile at coordinate.....' and then just the image where you spotted it, it wouldn't be so much the latency as the bandwidth reduction.
lxgr · 22m ago
In-orbital-plane data processing is an interesting idea! Laser links are much simpler to do between satellites in the same plane than across planes or even down to Earth.
matt-p · 23m ago
But that's embedded compute on a satellite isn't it, not a data centre in space.
BirAdam · 34m ago
Yeah, it would make more sense to put some DCs in Patagonia.
amelius · 53m ago
Read the "Thermal Management" section, page 8 ...
echoangle · 28m ago
I believe that it’s physically possible to build something like this, but there’s no way it will be cheaper or simpler than cooling on earth. In their comparison table (table 1), they have earth based cooling for a 40 MW cluster over ten years at 7 million dollars and on the right side calculate the space cost as $0 (although they only imply that it would be cheaper than on earth by saying it’s „more efficient“). If you believe that their cooling system will be less than 7 million with enough redundancy for 10 years (or alternatively maintenance or replacement missions), I don’t know what to tell you. It’s not happening.
matt-p · 22m ago
Even if the cooling system was free p&p will be $7 million.
p1necone · 42m ago
I read it, it sounds like they also understand it would require more engineering effort and size/weight/materials than cooling something terrestrially.
alfiedotwtf · 59m ago
I got to the comma in the first sentence from the webpage and immediately went to the comments because I had the exact same thought.
Given Y Combinator's vetting process, I'm sure they would have tackled this problem somehow - maybe by feeding the heat into another process? It will be interesting to see how they've solved this.
vermilingua · 46m ago
> Given Y Combinator's vetting process…
The vetting process of the fund that quite famously invests in the founders over the idea?
echoangle · 40m ago
I hope that’s what’s going on here. They can’t seriously fund something like this and expect anything close to the pitched output.
But I also wouldn’t fund the founders here because they have to be incompetent or grifting. I seriously don’t see any other way, it’s that ridiculous.
xnx · 33m ago
> the founders here because they have to be incompetent or grifting
Bold grift may be what they're selecting for
shantara · 2h ago
Scott Manley has published a video a few months ago explaining why putting data centers in space is an absolutely terrible idea. Lumen Orbit, the company mentioned, is a former name of Starcloud.
Formerly known as "Lumen Orbit", or for short, "Lumon".
The work is mysterious and important. Praise Kier.
CobrastanJorji · 1h ago
I'm not an engineer, so maybe I'm wrong, but isn't cooling famously difficult in space?
godelski · 34m ago
Yes.
Also, so is heating.
When you're on the sun side, everything is too hot and it is hard to cool. You can do direct cooling, such as water cooling, but you have no radiator to dump the heat to...
When you're in the shadow of the sun you have the opposite problem. Things are way too cold. Cold enough normal electronics can fail.
For reference, the ISS can fluctuate between -250F and 250F.
I'm willing to bet that it is easier to deal with the issues of salt water than it is to deal with the heating and cooling issues combined with difficulty to manually access problems presented by space. Price per pound into orbit is still quite expensive...
ianhowson · 2h ago
I had a good laugh.
- You can't build 40MW of solar panels for $2M, even with theoretical maximum efficiency. You can't even build the cabling and regulators at that price.
- You need battery storage -- not as your backup -- but as primary source. It is going to cost more than $2M. Batteries are heavy. They are going to cost a lot to launch. This is not even solved on the ground yet.
- You need a heat transport medium to move heat into your massive radiator. Either you use water or you use air or you use heatpipes (metal). You have to pay for the cost and weight and launch expense. This is probably half the weight of the rack and I haven't bothered to do the math about how you transport heat into a 500 foot solar sail.
- Let's not even talk about how you need to colocate multiple other racks for compute and storage. There aren't any 1TBps orbital link technologies.
- Rad shielding? It doesn't work, but I'll let this slide; it seems like the least problematic part of the proposal.
- 15 year lifetime? GPUs are obsolete after 12 months.
I don't want to be the guy who shoots stuff down just for fun, but this doesn't even pass the sniff test. Maybe you can get 10x cheaper power and cooling in space. Still doesn't work.
amluto · 1h ago
Also: repairs. Every time I read someone’s story about large-scale ML training, a bunch of it is about identifying failing or flaky equipment and fixing it. That’s not so easy in space.
Havoc · 5m ago
I thought rad shielding works?
Just that it tends to involve heavy AF materials like water
mortoc · 7m ago
If you have continuous sunlight, can't you get away with no battery?
Not arguing with your overall point - this company looks ridiculous.
Retr0id · 11m ago
> You need battery storage
How so? Is it not possible to position the satellite in an orbit that keeps it in perpetual sunlight?
rozap · 1h ago
Either this is performance art, or interest rates are too low.
9991 · 34m ago
Or it's a cover for putting something else up in orbit secretly.
postalrat · 1h ago
Where do I buy some of these 12 month old obsolete GPUs?
Retr0id · 33m ago
eBay works for me
BonoboIO · 51m ago
Good point, Rad shielding … how even trust your calculations when everything is grilled by charged particles.
ekianjo · 1h ago
GPUs are not obsolete after 12 months. Look at how Nvidia is stagnating for their 50 series lineup.
The biggest problem is software. The CUDA stack is not maintained forever and certainly less than 15 years.
alfiedotwtf · 51m ago
Most comments on this page are about the problem with heat. You're saying the problem is battery storage.
... couldn't you just merge both problems into a solution - your radiators ARE you power source
kaonwarb · 11m ago
Temperature isn't a power source; heat flowing across a temperature gradient can be. But that brings us back to the first problem - how to make it flow.
GolfPopper · 44m ago
The use-case for this is not anything technical, it's putting your data center outside of any jurisdiction.
ceejayoz · 19m ago
The Sealand folks found rapidly that “outside any jurisdiction” also means “not protected by one”.
vonneumannstan · 2h ago
Unless they've figured out some impressive cooling tech, which I would expect would be worth more than the rest of their company combined, then this is pretty much DoA. "More efficient cooling architecture taking advantage of higher ΔT in space" would indeed be useful if you had a nice medium to radiate into. It turns out that thermal radiation is incredibly poor into the vacuum of space lol.
amluto · 1h ago
Space (with a sunshade) is a nearly perfect medium into which to radiate heat, in the sense that there’s nothing better.
But I agree with your general point. At 100°C, you can radiate about 1kW/m^2. That’s 1000m^2 of radiator per MW of datacenter, assuming you can operate with the radiator at 100°C. You can fudge this a bit with a heat pump (to run the radiator hotter, paying a linear-ish power penalty and gaining a fourth-power radiation benefit), but that’s expensive and that power isn’t free.
Here on Earth, you can cool by conduction or evaporation, which isn’t an option in space.
godelski · 27m ago
> Space (with a sunshade) is a nearly perfect medium into which to radiate heat, in the sense that there’s nothing better.
There is radiation but zero convection. As anyone with an oven or PC will tell you, even a very tiny fan makes a big difference in the ability to dump heat. We're not putting our PCs into vacuum chambers for a good reason. A small fan in your oven not only makes for more consistent heating in your food, but it requires less power
troymc · 34m ago
It might make more sense to put data centers on the Moon.
It's fairly close, about 1.3 light seconds away. You wouldn't use it for anything realtime, but it would be fine for long AI training jobs.
You could bury the servers underground to shield them from cosmic rays. That would also be good for any people living there.
You could get power from solar panels on peaks near the poles that get light almost all the time. For example, some ridges around Shackleton Crater are sunlit up to ~90% of the time, with short periods of darkness. Use batteries to smooth out the power supply.
For heating and cooling, just use the standard techniques. It's not easy, but it's a solved problem. As a bonus, near the poles, the temperature extremes aren't as bad as at the equator.
You could also sell tickets to tourists. People will pay to see the darndest things.
entangledqubit · 1h ago
Microsoft had/has the Natick project which was an undersea data center testbed which allegedly had a bunch of benefits. That doesn't seem to have gone anywhere - or at least isn't really scaling up. I'd imagine the ongoing operational costs of space are worse than the ocean?
To me, the cost estimates seem a bit off and conflate capital with running costs.
The main benefit for space at the moment seems to be sidestepping terrestrial regulations.
Havoc · 3m ago
Underwater makes a lot more sense. There you can dump essentially infinite heat
aylmao · 19m ago
> Microsoft had/has the Natick project which was an undersea data center testbed which allegedly had a bunch of benefits. That doesn't seem to have gone anywhere - or at least isn't really scaling up.
I think at the core of this there's a risk analysis. At one point I briefly worked in a team in charge of a company's servers, and there were plenty of stories of things gone wrong enough that someone had to drive or fly to the datacenter. These company's datacenters were named after the closest airport for this reason, iirc. A little optimization in case things went very wrong; you always knew where you'd have to fly in to.
Even if an undersea data center could potentially yield cost benefits, it's also significantly riskier in case something goes wrong. How long would it take to physically access a machine? Do you have to bring down other machines to access it? And at scale, things tend to always go wrong.
To comment on the original post, needless to say this is even more complicated, costly and untimely in space.
zamalek · 2h ago
What does space give us that Earth does not in this scenario? Free real estate? They only mention falling costs for deployment.
dilyevsky · 2h ago
There's an answer in their whitepaper[0] - see Table 1. tl;dr - power is continuous and free via solar array
It’s is on earth as well using solar and batteries. What is likely to get cheaper faster? Solar and batteries? Or lifting datacenters to space? The world is almost at the point of deploying 1TW/year of solar, and batteries are catching up. No space required. There aren't a lot of VC investment opportunities speeding the rate of solar and battery deployments though.
CobrastanJorji · 1h ago
Just spitballing here, but what if you built it on Earth, and then used the savings to build a second one on the opposite side of Earth? Now you have equivalently continuous power via solar array and also, as a bonus, air.
richardwhiuk · 1h ago
Free in the sense of astronomical capital and operational costs.
dilyevsky · 1h ago
r&d sure, not sure about ops as you can probably just detach a faulty module and launch a replacement.
GTP · 1h ago
Not an expert in this area, but I think that that "just" is hiding a lot of complexity. Plus you also need some remotely operated robots to mount the replacement.
SahAssar · 1h ago
Stationkeeping is not free, satellite monitoring is not free, and any replacement to any component is now a multi-year, at least 1+ million dollar affair (or most likely a complete replacement, since not many satellites have done in-situ repairs).
richardwhiuk · 1h ago
Relaunching is effectively operational cost.
zamalek · 58m ago
Power in needs to equal heat out, and that isn't easy in space. They, deceptively, claim that their novel solution is radiative cooling. Relying on radiation for cooling in space is the problem statement! Convective (as on Earth) is significantly more effective.
I'm not one of those idiots who would claim that "we should focus on terrestrial problems instead of space," but this idea seems to have only downsides.
cj · 1h ago
> “We still don’t appreciate the energy needs of this technology… there’s no way to get there without a breakthrough… we need fusion or we need radically cheaper solar plus storage or something” -Sam Altman
It's kind of depressing that the only way to make this tech better is to feed it more energy. (And apparently now to send it to space)
jebarker · 1h ago
It's also interesting that everyone is convinced the same capabilities can't be realized with drastically less compute.
tux3 · 2h ago
[flagged]
xnx · 2h ago
I do wonder about data centers in the arctic. Cut out the middle step of greenhouse gases and melt the polar caps directly.
chewbacha · 2h ago
Not to mention the benefit of directly harming extremely vulnerable ecosystems! Win-win
btown · 2h ago
[flagged]
dang · 1h ago
Can you please make your substantive points thoughtfully, without snark or putdowns?
It is, to be fair, a shockingly incorrect claim in the context of vacuum.
dang · 2h ago
Can you please not post comments like this? Thoughtful criticism is welcome, of course, but this sort of thing isn't. Besides breaking the site guidelines, it takes threads in less interesting directions and evokes even worse comments from others. We're trying to avoid that here.
"Don't be snarky."
"Please don't post shallow dismissals, especially of other people's work. A good critical comment teaches us something."
"Don't be curmudgeonly. Thoughtful criticism is fine, but please don't be rigidly or generically negative."
Really, on second look, snark still feels justified here. The issue is with TFA. There is little room for a thoughtful comment in response to something transparent.
Some type of submissions will invariably not result in very deep discussion, when the topic itself is so shallow.
toraway · 46m ago
Tbh your moderation is normally very restrained and even handed so was a bit surprising to see you take down several borderline overly snarky comments in a row (that just so happen to be directed against VC investors or YC founders).
thekoma · 2h ago
How does “passive cooling” work in space?
Lanzaa · 2h ago
Passive cooling refers to "passive radiative cooling"[0]. This is a well established technique, but I have doubts on how well it will scale with the heat generated by computation.
Radiative cooling works by exploiting the fact that hot objects emit electromagnetic radiation (glow), and hot means everything above absolute zero. The glow carries away energy which cools down the object. One complication is that each glowy object is also going to be absorbing glow from other objects. While the sun, earth, and moon all emit large amounts of glow (again, heat radiation), empty space is around 2.7 Kelvin, which is very cold and has little glow. So the radiative coolers typically need to have line of sight to empty space, which allows them to emit more energy than they absorb.
Massive radiators. The ISS has radiators that have a dissipation capacity of about 3m^2/kW. If we use that number, we'd need a 3000m^2 radiator per megawatt, which is the scale they're talking about. This could theoretically be brought down, but not even by an order of magnitude.
I wonder how much cooling the solar panels alone would need, when operating at that scale.
echoangle · 1h ago
The radiators on the ISS aren’t passive though, they have actively pumped fluid loops to get heat from the hot parts into the radiators.
alfiedotwtf · 46m ago
That's interesting to know. But since it's space, how do they then cool down the hot fluid?
echoangle · 36m ago
You cool the fluid by flowing it through the radiator. The radiator emits heat radiation into space and cools down the fluid. As long as the fluid is hotter than the equilibrium temperature of the radiator (determined by radiator, space and sun radiation), it will emit more energy than it receives and cool down the fluid.
Followup question, wouldn't nearly any cooling solution that works in space also work on the ground? Radiative cooling is the most basic/common cooling solution on the ground, the main challenge is just figuring out how to to move heat from the component to the radiator, which I don't think is solved by simply putting it in space?
krisoft · 1h ago
> Radiative cooling is the most basic/common cooling solution on the ground
Thats tricky. I know the heat exchange components are called radiators but most of the heat they give off is by convection not radiation. (At least here on the ground.) I heard 80%-20% rule of thumb.
But you are right in the broad strokes. Cooling is not easier in space. Mostly because you have no convective heat transfer.
> Most spacecraft radiators reject between 100 and 350 W of internally generated electronics waste heat per square meter.
donyccie · 2h ago
Same question
stephenhandley · 38m ago
I'm wondering why this is being proposed to be in space rather than at the lunar poles? Is it a latency question? I'd assume if this is being used for LLM training purposes and it is a relatively long training run, latency is less a pressing concern than bandwidth constraints before / after training?
Wouldn't the moon would provide better environment for debris shielding and regolith could be used to passively dump heat?
I'm way out of my depth here, so of course I asked ChatGPT 4o to come up with a three paragraph concept sketch for an LLM training facility based at one of the lunar poles:
<gpt>
A lunar pole is an ideal location for large-scale LLM training due to its unique advantages in thermal management and power availability. Near-continuous sunlight at the “peaks of eternal light” allows for stable solar power generation, while nearby permanently shadowed craters provide ultra-cold regions that can act as natural heat sinks — solving one of the biggest challenges of orbital compute: radiative cooling. Compute clusters could be housed in regolith-insulated modules, with heat piped into crater floors or dissipated through passive radiators embedded in the lunar terrain.
The architecture would be modular: prefabricated training units delivered by landers (like Starship) could be arranged into scalable compute farms. Power would be provided by solar arrays on crater rims, with supercapacitors or RTGs as backup. Data transfer wouldn’t require low latency, just high throughput, so high-gain antennas or laser links could periodically sync model weights back to Earth. With no atmosphere, lunar surface conditions are harsh but predictable, and maintenance could be handled robotically.
Compared to the estimated $480 trillion needed for space-based radiators to support orbital training, a lunar facility could achieve similar scale at orders of magnitude lower cost, leveraging the Moon’s surface as both a structural anchor and a thermal reservoir. As launch costs drop and lunar infrastructure matures, this becomes a compelling direction for off-planet AI training.
</gpt>
jadbox · 31m ago
I guess it would be heat pollution at the poles that may contribute to global climate change if we start building immense data centers there.
stephenhandley · 14m ago
I believe they'd mainly need to be strategic about where and how deep they were radiating into the surface since there wouldn't be atmosphere that would trap heat.
Etheryte · 25m ago
Please don't litter HN with LLM generated slop. Each and every one of us here is more than capable of doing that themselves if they please. The value of HN is the human discussion.
stephenhandley · 21m ago
Lol you mind giving me a quick heads up on what have you contributed other than this meta gripe? Any concrete response to the actual questions I'm asking or just a soapbox?
Can this possibly make financial sense even if launch costs were zero?
One NVIDIA DGX SuperPOD consumes 10 kW which would be ~500 square feet of solar panels and ~100 square feet of radiator area.
VladVladikoff · 1h ago
Even if they somehow figure out all these problems. how do you manage a space based data centre? do you have rotating staff living there? or are they just praying that nothing ever goes wrong??? Isn't radiation a massive problem in space? i would expect consumer grade hardware to be constantly flipping bits accidentally that shouldn't have flipped.
> Their design calls for a cluster of shipping container-style boxes packed with high-speed AI chips. These would be anchored at the centre of a 16 sq km array of solar panels generating up to five gigawatts of power — about 25 per cent more than Drax, Britain’s biggest power station. The mammoth structure would circle the Earth in “sun synchronous” orbit so that it is never in shade
semi-extrinsic · 1h ago
Their whitepaper clearly demonstrates a profound lack of knowledge of thermal engineering. E.g. heat pumps are described as magical things.
They are literally planning to feed the radiators using a coolant like water and sensible heat at 35 degC to 5 degC. At 5 GW, you then need to be pumping 60 000 liters of water per second.
That's like a tenth of the Sacramento river, going through a 16 sq km array in space and hoping that nothing leaks.
xnx · 22m ago
> 60 000 liters of water per second
Then they just need to worry about the extra friction heat generated by moving that much liquid.
ceejayoz · 12m ago
And what happens if there’s a power outage. Frozen pipes aren’t all that fun.
xnx · 1h ago
A continuous five gigawatts of power would be seriously impressive. I think that's about $12 million/day (terrestrial prices).
That is pretty amazing to say with a straight face. Whatever GPT6 may or may not ever be…
arp242 · 1h ago
Reading the paper this sounds like space Theranos. If they start producing results then I'd double check to make sure it's not just calculated on regular data centres and that they're just pretending its from their space stations.
Aside from the technical concerns already raised in other comments, I'm also not sure we really want all this private for-profit usage of earth's orbit. The orbital environment is already somewhat congested and people have already been raising concerns about it. There is the potential for it all to spectacularly blow up in our faces and become so polluted that we won't be able to do many launches at all.
ChuckMcM · 24m ago
"Space Theranos" wins the day for me. There really needs to be a better term than "stupid money" for investors who can be convinced with a slick presentation that by investing in a venture the principals will bring to market products that violate the laws of physics.
bitmasher9 · 1h ago
Private use of previous public resources has had mixed success, but it feels like leaving space to the public sector will doom us to being Terran bound forever.
aunetx · 56m ago
I don't see the problem in that to be honest... Especially if the other solution would be allowing private companies to take over our (shared) orbit, meteorites, and -- continuing the trend -- planets for themselves to profit. If it seems overly pessimistic, we can just look at how our own planet's ressources are shared...
conn10mfan · 31m ago
the private sector made it to the moon 56 years after the public sector
it's going to take the management of our shared resources and spaces (orbit) for instance to leave earth, and this becomes especially important as Kessler syndrome risk rises with increasing debris in orbit
private companies launching without public oversight and controls are a recipe for cluttering earth's orbit and leaving us earth-bound for far into the future (same if the public sector launches without care but that seems less likely imo)
I don't know what the best solution is to be honest, but a wild west where improbable VC-funded nonsense is flung in to orbit isn't it. Leaving it only to the public sector is the other extreme end of course, and I'm not advocating for that either.
bitmasher9 · 1h ago
How do they plan on addressing the solar radiation issue? What is the solar flare risk?
A CDN for Starlink customers is probably the first use case for servers in space, not training GPT6, which will be a big enough project on familiar territory.
Townley · 2h ago
It sounds like their vision for space-based data centers presupposes nearly-free energy costs, delivered via a colossal solar farm made possible by falling launch costs.
Temporarily putting aside (extremely fair) feasibility questions around those two pre-requisites, data centers are a not-bad choice for things to do with unlimited space energy.
Aluminum smelting or growing food are the two I’d think of otherwise, and neither of those can have inputs/outputs beamed to a global network of high-bandwidth satellites.
gbear605 · 55m ago
Solar energy isn’t that much more efficient in Earth orbit than on Earth - maybe twice as efficient. That sounds nice, but you’re saving half of your solar panel cost while massively increasing every other cost.
ceejayoz · 2h ago
Isn’t cooling already a major issue for spacecraft?
The big radiators on the ISS can only dump a few server racks worth of heat.
andrepd · 10m ago
This is the best piece of satirical writing that I've read in quite a long time. It's genuinely amazing, every sentence is a delight. And the Musk/Altman/Zuck quotes to start, the stupid little graphs and the "equation" at the end of page 2. I'm in stitches!
UberFly · 2h ago
Most expensive IT call ever when you need to go fix that one fried power convertor that everyone said wouldn't fail.
divbzero · 2h ago
I was wondering if these server racks in space would need to be specifically designed for enough radiative cooling. Apparently the answer is yes: the radiators would be expansive and placed on the reverse side of the solar panels.
Starcloud is developing a lightweight deployable radiator design with a very
large area - by far the largest radiators deployed in space - radiating primarily towards deep space, which has an average temperature of about 2.7 Kelvin or -270°C. The radiators can be positioned in-line with the solar
arrays as shown in Figure 3, with one side exposed to sunlight.
…
Figure 3. A data center in Sun Synchronous Orbit, showing a 4km x 4km deployed solar array and radiators.
Definitely an out of this world idea. I wonder if their micro datacenter is going to be self-sufficient power wise using only solar energy? And how would they address the hardware failures that are likely when you train large language models at scale?
abetaha · 1h ago
The white paper back of the envelope calculations show a 4km x 4km solar panels and radiators are required for a 5 GW datacenter. I am not sure how the authors were not cracking up while writing that white paper.
827a · 1h ago
Given the purported cost benefits in their whitepaper [1], hardware failures might be an irrelevant rounding error. They suggest something to the tune of 100x cheaper.
wow, one year back, I had made a prediction to a friend that this is the direction that Starlink will head in. I was thinking it would proceed like this:
1. provide internet.
2. provide CDN.
3. Edge Compute.
4. Full-on cloud.
These guys see to be focussing on what is basically offline processing (AI training).
thrance · 1h ago
More like, these guys will be focused on parting VCs from their money.
Datacenters in space makes no sense at all. Even ignoring the huge cost of sending hardware there in the first place, cooling is a massive issue in space. No medium to sink heat into means the only way to cool anything is by running water through giant infrared radiators. Not ideal when cooling is the largest bottleneck in scaling datacenters. Note that they would also have to dissipate the large amounts heat their datacenter satellite gets from being exposed to the Sun.
Also disregard the cost it takes to send a technician for maintenance, of updating hardware, etc.
ekianjo · 1h ago
> Also disregard the cost it takes to send a technician for maintenance, of updating hardware, etc.
This won't happen. If a satellite fails they will just write it off. Maintenance would be more expensive than depreciation
ceejayoz · 10m ago
They’re proposing a multi-kilometer sized satellite, though. That’s more akin to demolishing an entire datacenter when something important fails.
vanilla · 2h ago
space debris, radiation and no maintenance.
The buzzwords sure sound cool, but make absolutely no sense.
pauletienney · 2h ago
Make something hard harder, just because
davidczech · 32m ago
Data center on Mars.
I will call it MartianCloud.
arm32 · 1h ago
It'll provide Earth more shade from that pesky sun!
Glyptodon · 1h ago
Does abundant cooling in space mean there's a better way to radiate away heat than on Earth or just that the heat doesn't contribute to heating up Earth or something more complicated? (Asking because I thought cooling was a big problem in space.)
niek_pas · 1h ago
I miss when tech was exciting
jsheard · 2h ago
Aside from the obvious cooling issues people have already mentioned, isn't cosmic radiation also very unkind to modern ultra dense silicon? AIUI they tend to use really old silicon processes in space stuff for that reason, and even then they have to build in redundant compute to mitigate logic errors that probably wouldn't happen on Earth.
NitpickLawyer · 1h ago
> They tend to use really old silicon processes in space stuff for that reason.
To be fair that's mostly part "if it works don't change it" and part "that's how we've always done it". SpX uses newer hardware w/ traditional OSs (linux) w/ lots of redundancy.
megiddo · 1h ago
This. Had to deal with cosmic rays on earth in data centers 20 years ago.
I can't imagine running bleeding edge GPUs in a particle accelerator and getting reasonable results.
ekianjo · 1h ago
Does SpaceX also use old silicon for Starlink and other projects?
jsheard · 48m ago
I believe they use relatively modern silicon in Starlink, but the nature of a constellation gives them a lot of wiggle room to route around failures.
MattSteelblade · 1h ago
This doesn't pass the sniff test. Please, show me the napkin math where this remotely adds up.
mark242 · 2h ago
And what happens to these datacenters when the underlying GPU tech becomes obsolete within 2-3 years?
Bedon292 · 1h ago
I would imagine you could launch a new rack, dump the old one, and connect the new one to the existing solar / cooling array. Hopefully with some sort of re-entry and recycling plan for the old one. The sheer size the arrays are going to need to be feel like they are going to be the more important part of it.
floathub · 1h ago
Canadian north makes sense (very cheap electricity, ridiculously easy heat management).
Space? I really don't get it.
WhitneyLand · 1h ago
Suggest changing the elevator pitch text - it’s never going to make sense to train a frontier model in space. In our lifetime at least.
varunneal · 1h ago
I'll take the long side on that bet
settsu · 1h ago
I guess since we decided Idiocracy was aspirational, why not Wall-E as well.
/s (kinda but maybe not really...)
crispinb · 1h ago
Ycombinator has one legitimate function: dissipating excess looted wealth.
znkynz · 2h ago
Can't wait to experience a Gigawatt DC re-entering a la Cosmos 482.
rzzzt · 2h ago
Free hardware delivered to your doorstep!
serjester · 2h ago
Very ambitious but it seems futile if you’re not building the rockets yourself. Personally I’m more bullish on figuring out how to use analog chips to train models.
Havoc · 2h ago
>passive cooling
huh? I was under the impression that cooling in space is an absolute nightmare since radiating heat into vacuum is super hard?
Even the comparatively small and decidedly H100-free ISS needed giant radiators
These two words are a massive red flags, signaling this is nothing more than a giant grift, like most of today's economy.
IAmGraydon · 45m ago
I very much agree here. This is clearly nothing more than a scam meant to separate investors from their money. I read the "white paper" and very few of their suppositions actually hold water, as many others have detailed in this thread. It seems like what this kind of "startup" does is pick two or three trending words, put them together and make up a story that would be believable to people who don't dig too deep. These guys chose the words "AI" and "space" and figured out how to stick them together. Speaking of that, anyone want to invest in my new quantum blockchain technology?
babuloseo · 2h ago
How I sniffed and stole training data and model data over the air to "Starcloud" posts gonna be crazy amount in abundance
ryandamm · 1h ago
Cooling in space was covered by XKCD's Randall Munroe in pretty entertaining detail here:
TL;DR... cooling in space isn't passive, you're on the "inside" of an enormous vacuum flask. And radiative coupling with space is possible from the ground, if that's what you're interested in:
But god bless crazy entrepreneurs. Don't ask whether we can, definitely don't ask if we should, just ask whether it makes for good headlines...
thot_experiment · 41m ago
> passive cooling
what the actual fuck? my boys joseph and ludwig would like to have a word with y'all
in ideal conditions, your gpu putting out 600W will need about a square meter facing deep space to keep it at 80c, this idea is absurd on first principles alone, maybe if you have heat pumps you can push this but then you're dealing with on orbit fluid loops that you can't maintain, as i said, what the fuck?
MOARDONGZPLZ · 24m ago
Is this an elaborate joke? I believe so given all the very real physical problems with this, but “GPT-6” training was what pushed it undoubtedly over the edge to pure joke.
devops000 · 2h ago
When I read something like this I fell that I am wasting my time working on a B2B SaaS.
BonoboIO · 1h ago
This has to be one of the dumbest ideas I've seen posted here.
Just think about the sheer effort required to dump 1 BILLION watts of waste heat into space - the engineering challenges alone make this completely impractical.
Compared to this, Theranos actually looks like a solid investment. At least Holmes had working demos and big-name backers before it all fell apart. This doesn't even pass the basic smell test.
All these comments are acting like this is a major problem with VCs in general.
Is this not a major problem with YC, specifically? Our beloved orange site funded and accelerated these guys.
brador · 2h ago
Solar Radiation and bitrot/damage, how you solving it? Whats your shielding stack?
IAmGraydon · 1h ago
These venture capital scams are getting more and more creative...
jklinger410 · 2h ago
Dang that's very cool. As long as up and down bandwidth stay strong and reliable.
alanfranz · 2h ago
I doubt you need that much bandwidth or reliability. Training is “on site”, you just need to upload training material once, then download the trained model.
VladVladikoff · 1h ago
is this a joke? isn't cooling in space a really big problem? how does it make sense to run a data centre with huge cooling requirements in a place where cooling is very difficult to accomplish?
At first I thought the poles (of the planet) might be good. The cooling is basically free. But the energy and internet connectivity would be a problem. At the poles you can really only get solar about three months a year, and even then you need a lot of panels. Most of Antarctica is powered diesel because of this.
So the next thought was space. At the time, launching to space was way too costly for it to ever make sense. But now, with much cheaper launches, space is accessible.
Power seems easily solved. You can get lots of free energy from the sun with some modest panels. But to do that requires an odd orbit where you wouldn't be over the same spot on earth, which could make internet access difficult. Or you can go geostationary over a powerful ground station, but then you'd need some really big batteries for all the time you aren't in the sun.
But cooling is a huge problem. Space is cold, but there is no medium to transfer the heat away from the hot objects. I think this will be the biggest sticking point, unless they came up with an innovative solution.
> As conduction and convection to the environment are not available in space, this means the data center will require radiators capable of radiatively dissipating gigawatts of thermal load. To achieve this, Starcloud is developing a lightweight deployable radiator design with a very large area - by far the largest radiators deployed in space - radiating primarily towards deep space...
They claim they can radiate "633.08 W / m^2". At that rate, they're looking at square kilometers of radiators to dissipate gigawatts of thermal load, perhaps hectares of radiators.
They also claim that they can "dramatically increase" heat dissipation with heat pumps.
So, there you have it: "all you have to do" is deploy a few hectares of radiators in space, combined with heat pumps that can dissipate gigawatts of thermal load with no maintenance at all over a lifetime of decades.
This seems like the sort of "not technically impossible" problem that can attract a large amount of VC funding, as VCs buy lottery tickets that the problem can be solved.
> They also claim that they can "dramatically increase" heat dissipation with heat pumps.
Right, great idea. Start with the heat where you don't want it -- in the chip -- and pump it out to where it can't go anywhere. Then you can recirculate the medium back and have slightly older heat that you can mix with the new heat! It'll be a heat party!
It's just like a terrestrial heat pump, where you pump the heat out to where you have a huge environmental sink to transfer the heat to. In space, you have something like a hundred thousand hydrogen atoms per cubic meter to take up the heat. A HUNDRED THOUSAND! That's a bigly number, it must work out. We can always make those atoms go really, really fast!
Did an AI invent this whole scheme?
The whitepaper shows a 4km x 4km solar array, which is 1600 hectares (3200 International Space Stations). Would assume the array they're proposing would be cheaper since its structurally more homogenous, but $480 trillion dollars is a whole lot of money.
This is orders of magnitude easier than the original proposal -- and yet still nonsensical.
You have to find trillions of dollars of future launches to justify current valuations.
https://news.ycombinator.com/newsguidelines.html
Outside of that, accepting money and saying “I will simply solve the enormous problem with my idea by solving it” is not only normal, but actively encouraged and rewarded in the VC sphere. Suggesting that that way of operating is anything short of the standard that should be aspired to is actually seen as derisive and offensive on here and can get you labeled as gauche or combative.
For one, the cost they ascribe to the space bound solar array being only $2 million for 40 MW is pretty out there.
FWIW there's a reason that Sweden has a bunch of datacenters in the north that are peanuts compared to hosting in Virginia.
They're "poorly" connected (by virtue of being a bit out of the way), but the free cooling and power from renewables make them extremely attractive. There was a time where they were the favourite of crypto-miners for the same reason as they would be attractive to AI training farms.
Fortlax has some I believe; https://www.fortlax.se
-----
As for the meat of the paper. Anyone with a passing understanding of space will be quick to point out that:
A) Heat is a problem in space, it's either way-way-way to hot (IE; you're in the path of the Sun) or it's way-way-way too cold (IE; you're out of the sun) and the shift between the two means you need to build for both. You also can't dissipate heat as there's no air to take the heat away.
B) Power is not so abundant and solar panels degrade; a huge amount of satellite building is essentially managing a decline in the capability of hardware. That's part of why there are so many up there.
C) Getting reasonably sized hardware up there is beyond improbable, though I'll grant you that most of the weight in a computer is the cooling components and chassis.
D) Cosmic Rays. No electromagnetic barrier from earth and extremely tight lithographies. I mean... there's a reason NASA is still using CPU's measured in the megahertz range.
Their main tech breakthrough would have to be in this area otherwise the company is worthless imo.
This is a super cool idea and seems like perfect investor-bait. That's about where it ends.
Routing through starlink should have direct LoS at all times.
(probably not)
Yes, let's go ahead and finish melting the ice caps, great idea
There is no easy passive cooling in space, getting rid of heat is a major problem. And you need more redundancy because the radiation will crash your computers. And launch is very expensive of course.
And the whole presentation is completely ludicrous. Look at table 1 in the linked PDF and tell me you’re serious. There is no additional cost when sending a datacenter to space except launch cost and shielding? Building a server farm on earth is the same price as building a satellite you can launch on a rocket as long as you use the same computers?
Can I take the other side of this investment? Like an angel funding round, but selling short?
Otherwise when the big firms go public (A16Z etc.), options trading on their stock.
Venture Capitalists are already like reverse insurance companies. They cover lots of people in the hopes that one of them will hit a rare event and it'll pay for the others.
Buying shares of a single startup is sort of the equivalent of betting on a specific horse to win a race. But what's the equivalent of lay betting (betting that a specific horse will NOT win)? Shorting? But you can't short a private company.
But wait, venture capitalists are already betting that their startups will make money. What if they were willing to double down a bit and accept lay bets? Say there was a kind of specialized short agreement that let you say "here is $x, if in N years company Y has less than $z profit/revenue, I get K*$x. Otherwise, VC gets to keep my $x." You could sell it to VCs as a way to do options trading on their own startup investments, plus it'd be a good way to get the wisdom of the crowds or whatever.
Nonetheless getting rid of heat (by radiation) is possible, otherwise people would be roasted inside the ISS.
I'm sure all of these companies are advertising "ChatGPT in Space!" because that's what will generate hype and money, but what they'll actually be planning is very small edge data centers whose job is to reduce latency.
Whether that makes financial sense, I have no idea. But I am sure it's at least physically possible for a small enough data center.
That’s like saying „if you’re thirsty on a ship, getting thrown into the sea is actually really nice because you will be around a lot of water.“.
Physically, you could do it, but it won’t be simpler or cheaper than on earth. Except for constant solar availability, there are only downsides with this.
Reduce latency to where?
Given Y Combinator's vetting process, I'm sure they would have tackled this problem somehow - maybe by feeding the heat into another process? It will be interesting to see how they've solved this.
The vetting process of the fund that quite famously invests in the founders over the idea?
But I also wouldn’t fund the founders here because they have to be incompetent or grifting. I seriously don’t see any other way, it’s that ridiculous.
Bold grift may be what they're selecting for
https://www.youtube.com/watch?v=d-YcVLq98Ew
The work is mysterious and important. Praise Kier.
Also, so is heating.
When you're on the sun side, everything is too hot and it is hard to cool. You can do direct cooling, such as water cooling, but you have no radiator to dump the heat to...
When you're in the shadow of the sun you have the opposite problem. Things are way too cold. Cold enough normal electronics can fail.
For reference, the ISS can fluctuate between -250F and 250F.
I'm willing to bet that it is easier to deal with the issues of salt water than it is to deal with the heating and cooling issues combined with difficulty to manually access problems presented by space. Price per pound into orbit is still quite expensive...
- You can't build 40MW of solar panels for $2M, even with theoretical maximum efficiency. You can't even build the cabling and regulators at that price.
- You need battery storage -- not as your backup -- but as primary source. It is going to cost more than $2M. Batteries are heavy. They are going to cost a lot to launch. This is not even solved on the ground yet.
- You need a heat transport medium to move heat into your massive radiator. Either you use water or you use air or you use heatpipes (metal). You have to pay for the cost and weight and launch expense. This is probably half the weight of the rack and I haven't bothered to do the math about how you transport heat into a 500 foot solar sail.
- Let's not even talk about how you need to colocate multiple other racks for compute and storage. There aren't any 1TBps orbital link technologies.
- Rad shielding? It doesn't work, but I'll let this slide; it seems like the least problematic part of the proposal.
- 15 year lifetime? GPUs are obsolete after 12 months.
I don't want to be the guy who shoots stuff down just for fun, but this doesn't even pass the sniff test. Maybe you can get 10x cheaper power and cooling in space. Still doesn't work.
Just that it tends to involve heavy AF materials like water
Not arguing with your overall point - this company looks ridiculous.
How so? Is it not possible to position the satellite in an orbit that keeps it in perpetual sunlight?
The biggest problem is software. The CUDA stack is not maintained forever and certainly less than 15 years.
... couldn't you just merge both problems into a solution - your radiators ARE you power source
But I agree with your general point. At 100°C, you can radiate about 1kW/m^2. That’s 1000m^2 of radiator per MW of datacenter, assuming you can operate with the radiator at 100°C. You can fudge this a bit with a heat pump (to run the radiator hotter, paying a linear-ish power penalty and gaining a fourth-power radiation benefit), but that’s expensive and that power isn’t free.
Here on Earth, you can cool by conduction or evaporation, which isn’t an option in space.
It's fairly close, about 1.3 light seconds away. You wouldn't use it for anything realtime, but it would be fine for long AI training jobs.
You could bury the servers underground to shield them from cosmic rays. That would also be good for any people living there.
You could get power from solar panels on peaks near the poles that get light almost all the time. For example, some ridges around Shackleton Crater are sunlit up to ~90% of the time, with short periods of darkness. Use batteries to smooth out the power supply.
For heating and cooling, just use the standard techniques. It's not easy, but it's a solved problem. As a bonus, near the poles, the temperature extremes aren't as bad as at the equator.
You could also sell tickets to tourists. People will pay to see the darndest things.
To me, the cost estimates seem a bit off and conflate capital with running costs.
The main benefit for space at the moment seems to be sidestepping terrestrial regulations.
I think at the core of this there's a risk analysis. At one point I briefly worked in a team in charge of a company's servers, and there were plenty of stories of things gone wrong enough that someone had to drive or fly to the datacenter. These company's datacenters were named after the closest airport for this reason, iirc. A little optimization in case things went very wrong; you always knew where you'd have to fly in to.
Even if an undersea data center could potentially yield cost benefits, it's also significantly riskier in case something goes wrong. How long would it take to physically access a machine? Do you have to bring down other machines to access it? And at scale, things tend to always go wrong.
To comment on the original post, needless to say this is even more complicated, costly and untimely in space.
[0] - https://starcloudinc.github.io/wp.pdf
It’s is on earth as well using solar and batteries. What is likely to get cheaper faster? Solar and batteries? Or lifting datacenters to space? The world is almost at the point of deploying 1TW/year of solar, and batteries are catching up. No space required. There aren't a lot of VC investment opportunities speeding the rate of solar and battery deployments though.
I'm not one of those idiots who would claim that "we should focus on terrestrial problems instead of space," but this idea seems to have only downsides.
It's kind of depressing that the only way to make this tech better is to feed it more energy. (And apparently now to send it to space)
https://news.ycombinator.com/newsguidelines.html
"Don't be snarky."
"Please don't post shallow dismissals, especially of other people's work. A good critical comment teaches us something."
"Don't be curmudgeonly. Thoughtful criticism is fine, but please don't be rigidly or generically negative."
https://news.ycombinator.com/newsguidelines.html
Some type of submissions will invariably not result in very deep discussion, when the topic itself is so shallow.
Radiative cooling works by exploiting the fact that hot objects emit electromagnetic radiation (glow), and hot means everything above absolute zero. The glow carries away energy which cools down the object. One complication is that each glowy object is also going to be absorbing glow from other objects. While the sun, earth, and moon all emit large amounts of glow (again, heat radiation), empty space is around 2.7 Kelvin, which is very cold and has little glow. So the radiative coolers typically need to have line of sight to empty space, which allows them to emit more energy than they absorb.
[0] https://en.wikipedia.org/wiki/Radiative_cooling
I wonder how much cooling the solar panels alone would need, when operating at that scale.
Thats tricky. I know the heat exchange components are called radiators but most of the heat they give off is by convection not radiation. (At least here on the ground.) I heard 80%-20% rule of thumb.
But you are right in the broad strokes. Cooling is not easier in space. Mostly because you have no convective heat transfer.
https://en.wikipedia.org/wiki/Spacecraft_thermal_control?wpr...
> Most spacecraft radiators reject between 100 and 350 W of internally generated electronics waste heat per square meter.
Wouldn't the moon would provide better environment for debris shielding and regolith could be used to passively dump heat?
I'm way out of my depth here, so of course I asked ChatGPT 4o to come up with a three paragraph concept sketch for an LLM training facility based at one of the lunar poles:
<gpt>
A lunar pole is an ideal location for large-scale LLM training due to its unique advantages in thermal management and power availability. Near-continuous sunlight at the “peaks of eternal light” allows for stable solar power generation, while nearby permanently shadowed craters provide ultra-cold regions that can act as natural heat sinks — solving one of the biggest challenges of orbital compute: radiative cooling. Compute clusters could be housed in regolith-insulated modules, with heat piped into crater floors or dissipated through passive radiators embedded in the lunar terrain.
The architecture would be modular: prefabricated training units delivered by landers (like Starship) could be arranged into scalable compute farms. Power would be provided by solar arrays on crater rims, with supercapacitors or RTGs as backup. Data transfer wouldn’t require low latency, just high throughput, so high-gain antennas or laser links could periodically sync model weights back to Earth. With no atmosphere, lunar surface conditions are harsh but predictable, and maintenance could be handled robotically.
Compared to the estimated $480 trillion needed for space-based radiators to support orbital training, a lunar facility could achieve similar scale at orders of magnitude lower cost, leveraging the Moon’s surface as both a structural anchor and a thermal reservoir. As launch costs drop and lunar infrastructure matures, this becomes a compelling direction for off-planet AI training.
</gpt>
We should train AI in space [pdf] - https://news.ycombinator.com/item?id=41478241 - Sept 2024 (93 comments)
A bit more here:
Lumen Orbit - https://news.ycombinator.com/item?id=42790424 - Jan 2025 (2 comments)
VCs wanted to get into Lumen Orbit's $11M seed round - https://news.ycombinator.com/item?id=42518284 - Dec 2024 (2 comments)
One NVIDIA DGX SuperPOD consumes 10 kW which would be ~500 square feet of solar panels and ~100 square feet of radiator area.
> Their design calls for a cluster of shipping container-style boxes packed with high-speed AI chips. These would be anchored at the centre of a 16 sq km array of solar panels generating up to five gigawatts of power — about 25 per cent more than Drax, Britain’s biggest power station. The mammoth structure would circle the Earth in “sun synchronous” orbit so that it is never in shade
They are literally planning to feed the radiators using a coolant like water and sensible heat at 35 degC to 5 degC. At 5 GW, you then need to be pumping 60 000 liters of water per second.
That's like a tenth of the Sacramento river, going through a 16 sq km array in space and hoping that nothing leaks.
Then they just need to worry about the extra friction heat generated by moving that much liquid.
This plan seems about as realistic as Bluthton though. https://www.reddit.com/r/arresteddevelopment/comments/1gtyvv...
That is pretty amazing to say with a straight face. Whatever GPT6 may or may not ever be…
Aside from the technical concerns already raised in other comments, I'm also not sure we really want all this private for-profit usage of earth's orbit. The orbital environment is already somewhat congested and people have already been raising concerns about it. There is the potential for it all to spectacularly blow up in our faces and become so polluted that we won't be able to do many launches at all.
it's going to take the management of our shared resources and spaces (orbit) for instance to leave earth, and this becomes especially important as Kessler syndrome risk rises with increasing debris in orbit
private companies launching without public oversight and controls are a recipe for cluttering earth's orbit and leaving us earth-bound for far into the future (same if the public sector launches without care but that seems less likely imo)
Kessler Syndrome: https://en.wikipedia.org/wiki/Kessler_syndrome
A CDN for Starlink customers is probably the first use case for servers in space, not training GPT6, which will be a big enough project on familiar territory.
Temporarily putting aside (extremely fair) feasibility questions around those two pre-requisites, data centers are a not-bad choice for things to do with unlimited space energy.
Aluminum smelting or growing food are the two I’d think of otherwise, and neither of those can have inputs/outputs beamed to a global network of high-bandwidth satellites.
The big radiators on the ISS can only dump a few server racks worth of heat.
Starcloud is developing a lightweight deployable radiator design with a very large area - by far the largest radiators deployed in space - radiating primarily towards deep space, which has an average temperature of about 2.7 Kelvin or -270°C. The radiators can be positioned in-line with the solar arrays as shown in Figure 3, with one side exposed to sunlight.
…
Figure 3. A data center in Sun Synchronous Orbit, showing a 4km x 4km deployed solar array and radiators.
https://www.starcloud.com/wp
[1] https://starcloudinc.github.io/wp.pdf
1. provide internet. 2. provide CDN. 3. Edge Compute. 4. Full-on cloud.
These guys see to be focussing on what is basically offline processing (AI training).
Datacenters in space makes no sense at all. Even ignoring the huge cost of sending hardware there in the first place, cooling is a massive issue in space. No medium to sink heat into means the only way to cool anything is by running water through giant infrared radiators. Not ideal when cooling is the largest bottleneck in scaling datacenters. Note that they would also have to dissipate the large amounts heat their datacenter satellite gets from being exposed to the Sun.
Also disregard the cost it takes to send a technician for maintenance, of updating hardware, etc.
This won't happen. If a satellite fails they will just write it off. Maintenance would be more expensive than depreciation
I will call it MartianCloud.
To be fair that's mostly part "if it works don't change it" and part "that's how we've always done it". SpX uses newer hardware w/ traditional OSs (linux) w/ lots of redundancy.
I can't imagine running bleeding edge GPUs in a particle accelerator and getting reasonable results.
Space? I really don't get it.
/s (kinda but maybe not really...)
huh? I was under the impression that cooling in space is an absolute nightmare since radiating heat into vacuum is super hard?
Even the comparatively small and decidedly H100-free ISS needed giant radiators
https://en.wikipedia.org/wiki/External_Active_Thermal_Contro...
https://www.youtube.com/watch?v=EsUBRd1O2dU
TL;DR... cooling in space isn't passive, you're on the "inside" of an enormous vacuum flask. And radiative coupling with space is possible from the ground, if that's what you're interested in:
https://www.skycoolsystems.com
But god bless crazy entrepreneurs. Don't ask whether we can, definitely don't ask if we should, just ask whether it makes for good headlines...
what the actual fuck? my boys joseph and ludwig would like to have a word with y'all
in ideal conditions, your gpu putting out 600W will need about a square meter facing deep space to keep it at 80c, this idea is absurd on first principles alone, maybe if you have heat pumps you can push this but then you're dealing with on orbit fluid loops that you can't maintain, as i said, what the fuck?
Just think about the sheer effort required to dump 1 BILLION watts of waste heat into space - the engineering challenges alone make this completely impractical.
Compared to this, Theranos actually looks like a solid investment. At least Holmes had working demos and big-name backers before it all fell apart. This doesn't even pass the basic smell test.
https://startree.ai/products/startree-cloud
Is this not a major problem with YC, specifically? Our beloved orange site funded and accelerated these guys.
"Please don't fulminate."
"Don't be curmudgeonly. Thoughtful criticism is fine, but please don't be rigidly or generically negative."