For those questioning viability, there's a startup called Starcloud https://www.starcloud.com/ with a public whitepaper explaining a bit their hardware and economics https://www.starcloud.com/wp.
They've already had one small proof of concept launched.
Not trying to promote, I just heard about them on the ycomb podcast
Ideally you'd put it in an orbit that wouldn't shadow earth, since if it goes in front of earth in part of the orbit then it'll go behind earth (and be in shadow) for part of the orbit. They mention they'd want it in a dawn-dusk sun-synchronous orbit, which would be in sunlight all the time and would never shadow the earth.
They seem to not be counting the $1B of GPUs on either side, making the difference pretty small. They also think launching 200 racks of equipment into space will cost $5M.
Because launch costs and density are completely imaginary. The whole thing is predicated on launch vehicles they hope someone builds eventually. They also appear to have profoundly miscalculated their radiation shielding costs and amounts, but I'm not really motivated to calculate that correctly.
Yes, the physics are worse, and yes, the economics are worse, but data centers in space have the crucial advantage that they are out of range of the molotov-throwing arm of Joe Public (recently unemployed).
I dunno, considering how various insurgent groups manage to make some reasonably impressive rocketry, I have to believe that in a few years with AI assistance (abliterate all the things) knocking a LEO satellite out of orbit won't be that much harder than sabotaging an electrical substation.
We're talking about an exceptionally vulnerable target with a perfectly predictable path of travel here. And it's constantly emitting lots of RF making it easy to track. You just have to get near it and explode with shrapnel.
Totally illegal, of course. But it will be within the reach of millions of people if they want to do it.
I don't think "just move to space bro" is going to stop the pitchfork-mob.
Alphabet holds approximately 551 million shares of SpaceX (trading under the ticker SPCX), valued at roughly $94.1 billion, which represents about a 4% to 6% stake in the company.
why would they sell? because of ridiculously large the valuation is? like, I guess at SpaceX's valuation there's tremendous downside and little upside (x2 growth is unlikely when it's a third of the tech sector)
This. China's copying SpaceX's homework and the public/private system towards that is operating so efficiently, if SpaceX lets off the gas, US is going to fall behind off the next long term gold rushes like asteroid mining, and said space datacenters.
They invested $900 million[1] in 2015, and it is worth $94.1 billion today. Why sell? They also likely have restrictions on selling post-IPO, but I don't think you can trigger a "bank run" on a stock anyway; the price will just keep adjusting as you sell/buy until it gets absurd.
A bank run happens when everyone tries to withdraw all their money at the same time and the bank runs out of cash. Not really possible in the stock market where companies literally can create/destroy shares and there is a whole secondary pricing layer to it.
"A bank run happens when everyone tries to withdraw all their money at the same time and the bank runs out of cash. Not really possible in the stock market where companies literally can create/destroy shares and there is a whole secondary pricing layer to it." Sure, it's not possible for stocks to become insolvent in the same way, but if a large shareholder sells it could trigger a panic and greatly decrease the price.
Whenever I hear about this I can't help but be reminded of the Howard Hughes Glomar Explorer, where a hugely-expensive commercial project was actually part of a secret CIA initiative to recover a Soviet submarine: https://en.wikipedia.org/wiki/Glomar_Explorer
I'm not sure that's truly the case here, but it does seem like the tech Project Suncatcher is working on has at least some overlap with requirements for military SIGINT and in-orbit imagery processing.
Why would the CIA need Google's cover for any of that? The Feds have been flying spy satellites since the 1950s and there's plenty of classified satellite launches.
Because anybody near-peer to the US at this point has the capability to shoot down satellites, and anything launched on a classified satellite launch is a prime target.
While a bit tin foil hat-y, this is an interesting (conspiracy) theory, even while space datacenters aren't as impractical as some people try to make them to be.
Every time I'm reading about the technical challenges of these kind of projects, it reminds me how amazing our brains are, doing what they do with only about 30W
For real. It's an enormous problem solved only with 1) sheer scale, and 2) Science Fiction.
Both of those are expensive as hell, by the way.
Cooling via radiation follows Stefan–Boltzmann: P = εσAT⁴. Let's assume a good surface (emissivity ~0.9) at 300 K (27 °C) at 400 W per square meter per side. A flat panel radiating from both faces into deep space gets 800 W/m, not including the losses from, say, the Sun, or from IR coming off the Earth. Now, input power. Sunlight in orbit ~1,360 W/m², assume ~22% cell efficiency, we got 300 W/m². So each 1 MW compute, 3,300 m² of solar panel and minimum 1,200–1,500 m² of radiator.
In case ya didn't know - 1 MW is tiny from a present-day-datacenter perspective. It's like 8 racks. So we're talking orbital megastructures here, many many many square kilometers, and this is with all the best case assumptions, and magic radiator panels that never see the sun, or the earth, or the moon.
This is just the basic numbers here, by the way. There's a garbage truck full of other unsolvable problems if you poke your head in there.
Aside from the "Avoid Regulations" aspect, and the "Everything That Burns Deorbiting is Depreciation" aka "The Starlink Trick", I'm not sure what the hell the draw is.
No point in running them at room temperature. GPUs, etc. run fine at 95 C. If you run your cooling loop at 70 C instead, you get 70% more cooling compared to 27 C.
At any rate, 1 MW for a single satellite is fine. Just launch several thousand of those and you get to real numbers.
Also, there's no need to talk about "magic" radiators. You orient them so they're at a knife edge to both the Sun and Earth. This is not difficult (the Moon is irrelevant).
Cooling in space is hard but not impossible - while current (IMHO stupid without advanced in space infra) space data center projects work with a couple MW, many advanced space propulsion concepts might have to reject hundreds of MW if not a couple GW.
As for space data centers - I think the main issue is the complete lack of in space infrastructure for resource mining, processing and manufacturing & maintenance. It is kinda like building your first practical steam locomotive & the deciding to build directly an airliner. No suitable materils, experience, work force, material sources, etc.
We eventually went from locomotives to airliner, in an incremental manner & expanding the supporting infrastructure to support the ever more ambitious projects.
It might be eventually doable, as an experiment or as a flex, sure. But it's never going to come close to being cost-reasonable versus the equivalent infrastructure here on earth.
What was it the 27th law that says radiating heat in to space does not work? I'm skeptical of the whole thing too, but it's not an impossible engineering challenge, just an expensive one.
The security advantages are enormous since access to space is so tightly restricted and controlled, compared to the access potential of a land based data center. Only risk in space is maybe we start WWIII with china and the US directly trading blows. On the ground, any insurgent group can disable your infrastructure. Nothing is truly safe on the surface of the earth. Anyone can strap a bomb on a drone now. See examples from the currently active wars.
It costs at least 50x more to put a GPU in space than it does on Earth. For that price you can have dozens more capacity in bunkers, under the sea, or on remote islands. Do you think your insurgents are going to get all two dozen? They could travel to the far corners of the earth, destroying 22 of them, and you'd still be ahead. Further, I wouldn't be surprised if a satellite with such a monstrous solar and radiator footprint wouldn't be susceptible to a laser based attack from the ground; either frying it or pushing it into an unstable orbit by vaporizing a few bits.
It costs much more than 50 times because there are no GPUs in space yet. Google is only planning to have some sort of space data centers mid 2030s, if everything works out. A big if, but if they don't start now then we'll never know.
What? No, exactly the opposite. It's very easy to jam radio signals and much harder to cut wires. There's a reason the drones on the front lines in Ukraine are dragging fibre optic lines these days.
There's probably so many ways to get around that with space based technology. I can quickly imagine several methods. It depends on what the system is for which might be a good method to use.
Method 1: same as how u2 planes dumped their data: air drop physical media containing data and catch it in the air.
Method 2: laser based emission to specific detectors.
Method 3: baseball style communication: station is under observation and manipulates in some way to serve as a signalling language.
Method 4: numbers station
Method 5: bill yourself as an isp and have some coded syntax that can be supplied in plain sight with the rest of isp traffic.
Method 1 runs into the problem of how to replace that media. The DC is in space so it's not like with U2 planes where they landed. Also, I think you mean the keyhole satellites and not U2 planes, since a plane lands at a secure site and can offload media then.
Method 1: Sure datacenters with latency measured in several hours sure are useful, and can also be intercepted
Method 2: Can be jammed by drone with laserpointer.
Method 3: Let me just transfer gigabytes of data via physical signalling
Method 4: Can still be jammed
Method 5: Can in fact still be jammed?
According to Wikipedia this reduces weight and not the required area. Also AI said the same thing, but I can't trust in it this blindly. So, how smaller would be the required surface area?
> Now, input power. Sunlight in orbit ~1,360 W/m², assume ~22% cell efficiency, we got 300 W/m². So each 1 MW compute, 3,300 m² of solar panel and minimum 1,200–1,500 m² of radiator.
We need > 2x more solar panels than we need radiators. Doesn't this imply radiation isn't really the limiting factor here?
Getting the energy back from the solar panel is easy via copper cables. Getting the heat back out there to the radiators is a bit harder, you needed fluids and pumps and heat exchangers which have lots of moving parts and need maintenance.
Doing it in a cost and weight effective way is still a big deal, because if it's not within ~10x the cost of ground based data centers, not enough people will use it to justify building it.
Radiating 1MW at 500K (227C) with a 0.4MW heat pump takes about 200 m^2 flat sheet surface. Inputs - solar+nuclear for double fun. So - quite feasible.
Moves 1 MW of heat with 0.4 MW of work? I.e. 2.5 COP {coefficient of performance). That's insane, and I mean that in a good way. Could you dig me up a cite for that?
That's thumping the Carnot limit: [[T_cold / (T_hot − T_cold)]].
2.5, while rejecting at 500 K, cold side's at least 357 K (eeehhhhhhh 84 °C) . . . and that's an absolutely perfect Carnot machine. At 50% Carnot -- a pretty good heat pump, real world performance is 40-60 -- cold side's at 417 K (144 °C). 417k, feeding your GPU coolant loops.
Do we even _have_ semiconductors that can work at 220C? And if you're thinking about using some kind of refrigeration cycle, its efficiency is going to be bad.
1) The chips don't reach 220C. The 220C is the temperature at the hot end of the heat pump. The chips are on the cold end of the heat pump.
2) The International Space Station has used a dual-loop ammonia/water-based heat pump to cool the station temperatures. It's been in place for several decades. Heat pumps are a proven technology.
> The 220C is the temperature at the hot end of the heat pump. The chips are on the cold end of the heat pump.
If we want the heat pump's cold end at about 40–65°C, then for each 1MW of GPU heat, we need another 1MW of heat pump power. Now you need 2MW of solar power.
Good news is that the radiator at 227C (500K) can emit about 5× more heat per square meter than at 57C (330K)
Getting this all up into orbit it obviously the hard part, but if you're already building so much solar capacity the cooling actually doesn't seem unreasonable?
Surface area is a materials problem? Folded microstructure, atomic-scale textured surface or some other science-fiction solution could have square kilometers of surface area in a shoebox.
Imagine you have two blackbody radiators with the same bulk properties, except one has surface area shenanigans like aerogels. In the far field as a whole, it seems like both should radiate essentially the same regardless of the internal details. You can shape emissive direction, or improve efficiency of non-ideal materials, but even ideal materials don't fix the issues pointed out by the parent.
Right; it's only area exposed to the exterior that counts. A physical object can't thermally radiate more power than a perfect blackbody spanning its convex hull.
(This follows because a physical object can't absorb more light than a perfect blackbody spanning its convex hull. A perfect blackbody by definition absorbs 100% of incident light, which is a hard upper bound. Any line incident on an object is also incident on its convex hull).
(Consider an isothermal object that emits more power than a blackbody in the shape of its hull at the same temperature. If you were to place that object in a closed system at thermal equilibrium, the interior of an insulated emissive sphere—combining assumptions, it would emit more power than it absorbs, in violation of the 2nd law. Starting from an isothermal system, the object would grow colder, and the enclosing container hotter).
Great read, thanks for sharing. I am interested in reading some more about the other unsolvable problems that exist in this space, do you have any recommendations that you wouldn't mind pointing me at? It would be greatly appreciated, and thank you :)
I don't think so. Large surface area helps with convective cooling I think by increasing the surface area that participates in heat exchange with the air (or other thermally conducting material), radiative cooling wouldn't benefit from this because you can't concentrate light beyond the source that it's emitted from (etendue).
Though I do wonder if it would be possible to have some kind of internal heat pump driven by electrical power to juice up the temperature of the radiators to increase the power being radiated away? E.g., run a heat pump to increase the temperature of a working fluid and then run high temperature radiators? I think it would work and I don't immediately see that it would violate the laws of thermodynamics? (this is ignoring all practically, I'm sure the engineering would be devilishly hard, although if you're already shooting for the moon you might as well throw in some artificial gravity to boot, it's not like the robots get motion sickness)
the other is that you could make tiny datacenters and flood the sky with them. in effect, not datacenters at all, but some kind of dataswarm coordinating at literal lightspeed via lasers.
they'd still be wildly expensive to deploy, and probably litter the orbit zone with fast-moving debris.
Your "other" makes no sense. It doesn't matter if you make a few big or a lot smaller, in space you will still need the same space for the same amount of megawatt. Or did you miss the scale of parent's post ? Because in that dream scenario of "let's ignore all the issues except that" and "the earth and the sun don't have any impact", it's still 3 THOUSANDS square meters for a MW of 8 racks.
You want to go smaller and go one rack only sure, it's still hundreds of square meters. Check the size of current orbital structure for a point of reference, you can't dwarf those and call it a "dataswarm of tiny datacenters flooding the sky".
From the article itself, sounds like it’s an open problem that they are experimenting with:
“ We’re working on a number of different approaches for this, including a combination of heat pipes and radiators to cool the chips. So far, our team has tested the technology in a thermal vacuum chamber that simulates both the thermal and vacuum environment in space. We’ll see how our new TPU cooling system works in space and refine our designs as we learn more.”
> The biggest challenge was how to cool the A.I. chips, which heat up when they perform calculations and process information. Fans, which typically help dissipate the heat, do not work in space. So the Silicon Valley company instead developed a cooling system that uses layers of conductive material to expel the heat into space.
> The bottom layer is made up of Google’s A.I. chips, which sit on a green motherboard. The next layer consists of “thermal interface material,” a pale green putty that comes in sheets like Fruit Roll-Ups and connects the chips to layers of aluminum and copper, radiating heat away from the motherboard. Finally, there is a radiator panel, which projects heat into space.
> The chips can operate for about 15 minutes in space before needing to be shut down so they can cool off, said Travis Beals, Google’s senior director of product management for Project Suncatcher.
> The chips can operate for about 15 minutes in space before needing to be shut down so they can cool off, said Travis Beals, Google’s senior director of product management for Project Suncatcher.
you need a gradient from hot to cold to generate electricity. vacuum is a poor thermal conductor, so your cold part will become hot and then no more gradient.
(I guess you could try to capture the radiative photons via the photoelectric effect?? but I don't think it works.)
We don't. This is all cover for the militarisation of space, there's no real benefit that'd be ever economical to put a DC up in space when you could build one on the ground. The whole narrative exists to allow google to tap into the Golden Dome / Space force bucket of pork that's basically SDI II.
You don't need civilian scale compute in space, but you absolutely can put miliary application up there and get filthy rich, like Elon, who doesn't care if it ever works, because he's getting paid as taxi service to shoot stuff up.
This is the most interesting perspective I've heard on this topic, which otherwise always converges on the same political dismissals or heat dissipation arguments (the latter are fascinating, but going in circles by now).
Sounds very probable: gives a plausible reasons for sending a lot of infra up, absolutely doesn't have to be profitable or even effective, puts the focus on AI instead of the MIC, and is in line with the kind of contracts Big Tech runs after.
To me this model explains a lot of why so many big companies seem to be investing into what every expert I've heard says goes against basic physics. The only thing missing for it to be more than an interesting idea is why China and the EU are not fighting this.
He is free to launch his own space GPU if he is so confident it is profitable*.
I will take it as a given that the Google engineers know what they are doing, and their first version can only run for 15 minutes before it needs to shut down to cool.
*Profitability requiring that other Musk controlled companies do not pay for the service at elevated rates in a classic self dealing scheme.
> He is free to launch his own space GPU if he is so confident it is profitable*.
Are you not aware that's exactly what SpaceX is doing?? https://www.spacex.com/spacexai/starmind Sure, it's now SpaceXAI or whatever, but how is that any different than Google sending up sats and selling the compute via Gemini?
Please stop with this argument. This is one of the easiest problems to solve. Heat dissipation requires a radiator, which is just a dumb hunk of metal. All you need is a cheap way to launch mass to orbit, which is exactly what SpaceX (and Chinese companies) are doing.
The only valid argument against data centers in space is the economic cost. If the per megatoken price for space datacenters is higher than terrestrial, then this won't work.
But the price for terrestrial datacenters keeps going up and technology keeps dropping the price of space-based.
That is not a fake argument, but real physics. Yes, you can design out X kw can be dissipated by this much radiators, but that adds an enormous quantity of mass, more than the solar panels that feed it.
If you are trying to generate a profit, every extra kg puts you further in the red. It still costs over $1000/kg of mass to get into orbit.
So is it a physics problem or an economic problem? Sounds to me like you are acknowledging that it is just an economic problem. If it cost $1/kg to get to orbit then this wouldn't be a problem, right? Just make a bigger radiator.
But if it's an economic argument, then you need to do the actual math. How big is the radiator? How low could the price to orbit go? How much can you charge per million tokens in 2030?
The reason this is a fake argument is because the validity depends on the math, and nobody advancing the "you can't cool stuff in space" argument is actually doing the math.
The economics is constrained by physics. AI in space is not viable if it costs $1000/kg to launch to space. Starship promises to cut that down to $100/kg (more if you believe Elon, but most don't), but that's still not competitive.
Sure, things would be different if the cost was $1/kg, but short of somebody building a space elevator that's just not going to happen.
I won't believe less than $100/kg until I see it. I agree with you on that.
But are you sure that $100/kg is not competitive? I don't remember all the math, but even their initial AI1 design[1] would throw a lot of profit, if you can sell at the price they offered to Anthropic.
I suspect the price of manufacturing the satellite, plus chips, is the dominating factor, not necessarily the launch costs.
Okay any argument about why space is uniquely challenging is going to revolve around physics. Sure it's not literally physically impossible, but we need to explain to people why this is different from shipping the GPUs to Ohio.
If you want math then https://andrewmccalip.com/space-datacenters exists. The numbers are grim for orbital DC. Even if you drag the launch cost slider all the way to $1/kg (by the way this is literally sci-fi, per ChatGPT air freight of semiconductors from Taiwan to Ohio costs $9/kg and ocean/train freight costs a bit under $1/kg for a reasonable shipment so good luck with $1/kg to LEO this century) it is still more than twice as expensive as terrestrial DCs.
But that calculator shows most of the cost is in the satellite. At $8 per watt (or about $2 million per satellite) the cost of orbital compute matches terrestrial.
That sounds absolutely possible. But in any event, we're now arguing a different thing.
The only thing I'm arguing is that cooling is a solved problem. I don't know if SpaceX will ever get the price down so that it is economical. But I'm convinced that there is no universe in which they hit their foreheads and say, "Oh no, we forgot about cooling!"
Note that this calculator is actually quite optimistic for orbital wrt. many things including cooling and effect on launch, as:
> No additional mass for liquid cooling loop infrastructure; likely needed but not included
> Thermal: only solar array area used as radiator; no dedicated radiator mass assumed
In hardware and mfg. solvable vs. solved is a big difference. And I too believe that SpaceX's engineers know about radiator panels. But the more cynical interpretation is that whatever the SpaceX engineers think about the technical merits, they are not being asked for that. They are just being asked for a pretext that justifies the xAI acquisition. Elon is also discussing lunar satellite factories that launch the satellites via railgun. Now, is this physically impossible? No, that isn't physically impossible either and I will seriously defend the physical possibility of this. It's not going to happen though.
And you could spend all the engineering costs on building some seriously efficient terrestrial DCs, but somehow all these analyses start with "assume that launch and satellite technology advances manyfold and terrestrial DCs stagnate or become less efficient, then if you squint the two numbers get kinda close."
It's a fundamental physics problem. You need to have huge radiating surfaces.
A 1GW datacenter with chips operating at 100C (which is probably doable) will need a radiator that has a surface of one square _kilometer_, and this is with all the favorable assumptions. Realistically you'll need about 2x of that.
If you want your DCs to be on a 1000km orbit (for reasonable ping times), you'll be able to _resolve_ these satellites with a naked eye!
The current plan is for 250 kW peak with 160 m^2 radiators. It will weigh about 4 tons so you can pack 25 on one flight of Starship.
Deploy 4,000 and you're at 1 GW. That's 160 launches.
BTW: SpaceX has already manufactured and launched 10,000 Starlink satellites and Falcon 9 launches about 150 times per year. None of this seems unworkable.
Can we solve the fertilizer price problem by hauling it with airplanes? Yes, we can! It's easy, just load the potash fertilizer into an airplane and unload it directly into the traincars. I even designed a neat conveyor belt system to speed up unloading!
Look at the numbers. 1kW of nuclear power capacity on Earth is around $2000, and that's 24/7 guaranteed power. So a 250kW cluster needs $500000 to cover its power demand with near 100% reliability and with some ongoing cost.
And if we're OK with some interruptions, then we can use solar+wind at around $100000 and with essentially no ongoing cost. If we assume the absolutely best projected launch cost of $100 per kg (vs the current one of ~$800), that's just 1 ton of material in space!
So you're off by 2-3 orders of magnitude in cost. And this kind of "it's unprofitable" is actually a fundamental issue.
Specifically, if SpaceX can get the price of a satellite down to $8 per watt (about $2 million USD) then it will compete with terrestrial.
I just don't understand how you can be so certain that they can't do that. I'm not certain that they can, but being certain that it's impossible seems completely evidence-free.
This calcualtor is bullshit (inflated terrestrial costs and underflated orbital costs). It doesn't pass the basic sniff test: $15B for 1GW of terrestrial power is more than enough to build AN ENTIRE 3GWe NUCLEAR POWER PLANT. From scratch. With 75 years of expected life.
So no, the calculations show that space is NOT feasible unless you want to do that for nefarious reasons: evading regulations, using AI for criminal enterprises, military use, that sort of thing.
Only these applications have the profit margin that even comes close to justifying it.
Not only that - it would be totally insane to launch something heavy & at the same time fragile from earth (under a lot of vibrations & heavy g-loading).
This is all a weird speedrun or race. If something we should be working on setting up resource mining from the Moon & asteroids, materials processing on the Lunar surface & in orbit, simple manufacturing in space, etc.
Instead some people think we can jump straight to a computronium Dyson swarm. :P
Now you've moved the goal posts. It's no longer "you can't cool stuff in space"; now it's "we can't launch a 10-gW compute cluster by the end of the year."
You don't need to send a multi-gigawatt satellite to space. You just need to launch a few thousand 250 kW satellites. That's not against the laws of physics.
> Please stop with this argument. This is one of the easiest problems to solve. Heat dissipation requires a radiator, which is just a dumb hunk of metal.
Convective radiation does not happen in space and this challenge is far more significant than your comment implies. Rather than "a dumb hunk of metal", radiators for spacecraft are often made of ceramics and carbon laminates with higher IR emissivity than convective radiators made of simple metals.
From the article you're commenting on:
> The chips can operate for about 15 minutes in space before needing to be shut down so they can cool off, said Travis Beals, Google’s senior director of product management for Project Suncatcher.
ML Infrastructure comes with some pros (larger emissive footprint) and cons (exponentially larger TDP) compared to the concerns there, but if you aren't familiar with the challenges of heat dissipation in space, please give it a read.
There's also a pretty interesting pop-sci article on cooling the Webb telescope, since it needs to be especially cold for its purpose. Not directly related, but may give insight into both challenges and solutions as well as well. https://science.nasa.gov/mission/webb/science-overview/scien...
Emissivity is one factor, but it is dwarfed by the T^4 term. Sure, maybe if you use exotic materials you can get from 0.9 to 0.95 emissivity, but why bother? Just run the radiators a little hotter.
The equation is:
A ~ (1000 P) / (2 e k T^4)
Where
A is the radiator area in square meters
P is the power in kilowatts
e is emissivity (usually 0.9)
k is the constant 5.67e-8
P and T are the dominating factors. Don't worry about emissivity.
Emissivity is an important factor here because as I said, and as the sources I linked for you to reference clearly stated convective radiation is not taking place in space.
Both Google and NASA are worried about this for a reason, if you think they are wrong, you should offer your assistance to them, rather than debating me.
Oh, sure yeah I agree with that. I was just making a point about the “big hunk of metal” comment and the fact that emissivity is important because the expense of radiator materials aren’t the problem - the surface area (and mass) of the radiator is.
And I agree with you on that. "Big hunk of metal" was too much of an exaggeration--SpaceX's design has liquid cooling, so I assume they have some channels or tubs running through the radiator, plus pumps, etc.
Never is a long time and you're relying on a bunch of unknowns like the cost of launch to orbit in 2030 and the future regulatory environment here on earth.
If you know all that out to 2040 then you must be a time traveler. Please try to fix our timeline rather than wasting time on HN.
and yet notice how the cooling video / section was the only one they didn't have a solution for... just saying "radiator" doesn't make sense - the radiator heats up too. it's how you get rid of the heat, not where you put it.
Huh? Radiators are known technology. They have them on ISS; they have them on every Starlink satellite. This isn't like warp drive or antigravity.
Moreover, you can easily calculate how big of a radiator you need for a given power level and temperature. You can use the Stefan–Boltzmann law:
A ~ (1000 P) / (2 e k T^4)
Where
A is the radiator area in square meters
P is the power in kilowatts
e is emissivity (usually 0.9)
k is the constant 5.67e-8
For a 1 kW test like Googles, you just need 1 square meter of radiators (assuming two-sided).
For SpaceX's 175 kW satellites, they will need ~170 square meters of radiators.
None of this is impossible or even difficult to calculate. That's why I think this is the laziest argument against space data centers. There are so many other more reasonable arguments (like whether they will be economically competitive) but people love to latch on to this one for some reason.
I think you misunderstand the argument of the people worrying about cooling. I don’t think most people think it’s literally physically impossible, they just think that this will be the thing that makes it economically uncompetitive. It’s a combined argument.
That may be the argument, but it's a dumb argument. Most of the cost is going to go to chips, solar panels, and launch. Radiators are probably one of the cheapest parts of the satellite: it's a hunk of metal with some pumps for liquid cooling.
People use that argument because it takes zero thought to make and significant effort to refute.
To your last paragraph: when opposing something, it makes sense to use the laziest argument first. Only if that doesn't achieve your goals, would you move towards less lazy arguments. I forget what the term for this is, it's generally criticized ("you should just put your strongest arguments first").
sure, the physics is solved: we know how radiators work, and we can calculate the area needed, blah blah. but we haven't put sustained-AI-computer systems into space yet - heat is a genuine concern, and personally I'm curious if they are developing something beyond simple radiators. if a ~1m^2 radiator works, great. but if the current test can only run the TPUs for ~15-minute bursts before it has to stop and dump heat, this issue isn't exactly "solved" in my book.
I don't understand your argument. Sounds like you're saying, "In theory it should work, but what if there are space pixies that keep rebooting the TPUs? What do we do then?"
The 15-minute figure is what they currently designed for because they have mass constraints. If they wanted a different figure (like forever) they could do it with a larger radiator.
As you said, the physics is solved! We know exactly how much heat a surface radiates in space--there is literally an equation for it. We know how to cool stuff in space. Will the price be low enough to make a profit? That's the real question. But stop worrying about cooling in space.
No one thinks we don't know how to cool things in space. Everyone is saying that it's not feasible because you'd have to put too much mass up. Stop derailing the conversation please.
If you have something useful to contribute regarding how to actually reasonably put up enough mass to make this remotely a feasible idea then please contribute. We have the technology to prevent global warming, and doing that is far easier than this, and yet even that is apparently not feasible for humanity.
I honestly don't get that. The current SpaceX design is for a ~4 ton satellite with 160 m^2 radiator with peak 250 kW output. You can launch 25 of those satellites on a single Starship launch. 160 Starship launches and you get 4,000 satellites with peak 1 GW compute.
What's unfeasible about that? SpaceX has already launched 10,000 Starlink satellites. Falcon 9 launches 150 times per year.
I don't think that is the argument, or if so it's an odd one because it's just a fact right now. Instead, people are claiming that it will never be feasible from a purely physics standpoint, which is something debatable.
If data centers in space end up being economically viable, then I don't see how anyone can catch SpaceX. They are ten years ahead in both launch capability and satellite manufacturing.
Chinese rockets companies are evolving at insane pace, including RLVs. A couple of big milestones have been achieved this year alone, like first stage landing.
I certainly hope ‘economically viable’ includes properly priced externalities for e.g. side effects of burning hundreds and hundreds of tonnes of aluminium and other materials in the high atmosphere.
No western company, no. That's why I can only hope SpaceX can get thru more red tape faster, and future administrations don't try to slow them down.
Even while current administration is kind of positive towards them, they are still even now just having to wait for no good reason for a FAA go-ahead. These kinds of stalls don't really exist in China.
Its only cheaper to build them on the ground if you aren't factoring security concerns. No insurgents in space. Not every application needs this hardening, but you can imagine there are many applications that do.
The useful life of cutting edge AI server hardware will require constant rotation of equipment to potentially remain competitive with more accessible solutions.
Hardening of equipment for the environment. ECC isn't going to be enough. I would have to defer to experts about the best way to manage it, but it either means custom hardware, weight, or both.
Repairs are impossible. Hopefully a sat can degrade gracefully, but routine repairs on earth become significant outages/decreases in economic value of a sat over time.
Rocket launches have gotten much better, but are not perfect. Insurance is a thing. However, cost of equipment in a failed launch may be eye watering, rivaling a governmental military launch.
To give a datacenter in space constant exposure to sunlight, the orbit must be either very var away, or occasionally be on the other side of the earth from you. Either way, the latency is terrible. You can put them in a ring and only choose the one closest to you, but are you really going to keep moving your data from satellite to satellite? So, bad for interactive use, maybe OK for non-interactive use, if you can afford the 30 foot by 30 foot solar panel and a similar size radiator for an 8x B300. That will be about $15M for your $500K GPU set. Plus $7M for the launch at SpaceX public rates.
I think these are mostly for llms or long-term storage where they are mostly concerned about latency within the data center and not latency between you and the data center.
Presumably they get exactly the same amount of sunlight 100% of the time instead of a few hours peak on earth? I'd say 8x is in the right order of magnitude.
The distance from earth to the sun is 150 million kilometers and your orbit is probably only a few hundred kilometers up (and realistically it’s sun-synchronous and perpendicular to the earth-sun axis), so the distance change doesn’t really matter.
From who? The crack addicts in space trying to steal copper?
The actual rack part is small, even if the solar panels and radiators are big. If this truly was super dangerous, ISS wouldn't be safe. And it's never hit mission-degrading issues due to micrometeoroids.
How is no one in the whole thread aware that the intention behind orbital datacenters is military? You want to process outputs of large space based sensors in space itself, and reduce latency (e.g to other space based assets) or increase goodput (to ground).
Either it's that weird "space is easier than getting land on earth"(it's not) or the same tortured arguments about heat dissipation, no one is going to run consumer scale compute with consumer scale economics in space ffs. And maintenance and cost does not matter when it comes to strategic military assets, they are a step function useful enough to warrant even a few monthly replacement.
Everyone else with strategic weapons and a space program e.g india china is launching one as well.
You can't launch from the US without the federal government giving you permission. And SpaceX does not have (nor are they planning) any launch pads outside the US. [And because of ITAR, I'm not even sure they'd be allowed to build one.]
However, I do think avoiding local control (state/city permits) is a reason for this.
As long as the company has a HQ and owners that care about their quality of life, they don’t really gain any extra safety by moving their hardware to space compared to keeping it where they are based.
What did he do that others considered unthinkable? This is not a rhetorical question. Please give me a concrete example, with sources proving experts in the field thought the idea was "unthinkable".
Robofactories? The idea was roundly mocked and completely failed, costing many millions of dollars, leading to manufacturing defects on thousands of vehicles, and delaying Model 3 mass production.
Hyperloops? The idea was roundly mocked and completely failed. Somehow it attracted hundreds of millions of dollars of investment. (There's suspicion Musk proposed the idea cynically to distract from rail.)
Robotaxis? Waymo started in 2004 and is, today, ahead of Tesla.
Electric cars? Again, demonstrated long before Musk got involved. The frustration amongst environmentalists at the time was that the technology and demand both existed but manufacturers weren't interested in making them.
(Before you claim the EV1 was so obscure as to not count, GM built about 1,000 of them, vs 2500 Roadsters. If it doesn't count, neither does the Roadster.)
Reusable launch vehicles? Work started on them in the '70s at the latest and they were the American workhorse by the '80s. The basic design SpaceX settled on was demonstrated in the '90s.
Satellite internet? Obviously old hat, so let's restrict ourselves to LEO constellations. These were proposed in the Star Wars project and were built by several companies in the 1990s. Starlink is much larger and more modern, but the basic idea was proven.
This narrative that Musk has done things other people considered impossible is simply untrue. Everywhere he's found success, other people had already demonstrated the basic idea. Everywhere the consensus was that he had lost the plot, he failed completely. Impressive work should not require exaggeration.
I will have to grant that this was previously unthinkable:
> Announced last year, Project Suncatcher is a long-term, research moonshot exploring whether space could one day host scalable machine learning infrastructure
It’s very confusing to have a project related to space called a moonshot project.
Haha, yes. I think Silicon Valley (the show ), made fun of the same thing. "Not so long ago, people called the idea of sending a man to the moon a moonshot"
The part I find wilder than cooling is the formation flying. If I remember their paper right, it's 81 satellites inside a 1 km radius, neighbours 100 to 200 m apart, because the optical links only get datacenter bandwidth over short distances. The ISS is about 110 m across, so that's satellites roughly an ISS-length apart, all doing 7.5 km/s
Earth will get bulldozed soon anyway to make room for that hyperspace bypass. The plans have been available in the local planning office for a while, but nobody knows about it because they're hidden in the basement and you have to go down there with a torch.
I think if those building the datacenters were more upfront about what they were building and didn't hide behind NDAs the permitting process wouldn't be so fraught.
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