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kin 2 hours ago [-]
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
stingrae 2 hours ago [-]
“A 5 GW data center would require a solar array with dimensions of approximately 4 km by 4 km”
I think dodging debris is challenging at that scale.
Also this is the solar cells not the radiators
flog 16 minutes ago [-]
I wonder if the shadows from such a large area would have a climate cooling effect?
glenstein 7 minutes ago [-]
I think the principle is correct but probably it would need to be much bigger.
FuckButtons 1 hours ago [-]
Presumably that’s not a single satellite.
efskap 45 minutes ago [-]
Right, the goal here is a more realistic Dyson swarm, not a Dyson sphere (yet)
a11r 1 hours ago [-]
That whitepaper puts the cost of a 40 MW cluster at $167m on land and $8.2m in space, inclusive of launch costs.
j2kun 22 minutes ago [-]
that sounds ridiculous. How could it be so much cheaper
stonogo 35 seconds ago [-]
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.
17 minutes ago [-]
bahmboo 44 minutes ago [-]
Starcloud seems like a whole lot of hand waving and BS. This is a good video that goes over their problems:
Curious what specific problem this solves that can't be done terrestrially. Bandwidth and latency from orbit sound gnarly.
nova22033 5 hours ago [-]
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.
foota 5 hours ago [-]
It's a little crazy they haven't tried to sell it off yet. Maybe they don't want to trigger a bank rush or they're limited in their ability to do so?
sterlind 4 hours ago [-]
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)
Andrex 4 hours ago [-]
I could also see some key decision-makers just being nerds that like space.
alexnewman 4 hours ago [-]
I don’t see how America or Google remain relevant unless SpaceX succeeds .
maxlin 2 hours ago [-]
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.
formvoltron 3 hours ago [-]
Huh?
altmanaltman 4 hours ago [-]
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.
>They invested $900 million[1] in 2015, and it is worth $94.1 billion today. Why sell?
Didnt you answer your own question? Most would consider a 100x ROI more than sufficient for taking profits
warkdarrior 3 hours ago [-]
$94.1B will barely buy you some RAM.
foota 2 hours ago [-]
"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.
fwlr 38 minutes ago [-]
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).
neuronexmachina 7 hours ago [-]
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.
motionlessveloc 5 hours ago [-]
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.
OkayPhysicist 5 hours ago [-]
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.
motionlessveloc 5 hours ago [-]
A foreign nation shooting down a US satellite would be an act of war, regardless of whether it's a Google or CIA satellite.
datadrivenangel 3 hours ago [-]
but 'accidentally' bumping it with space debris would be an 'accident'.
jryle70 1 hours ago [-]
Well, then American will "accidentally" shoot down their satellites. Nobody wants any of that.
maxlin 2 hours ago [-]
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.
aaron695 3 hours ago [-]
[dead]
zactato 9 hours ago [-]
How are they solving the heat dissipation issues?
lopsotronic 9 hours ago [-]
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.
SyzygyRhythm 53 minutes ago [-]
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).
octoberfranklin 7 minutes ago [-]
No point in running them at room temperature. GPUs, etc. run fine at 95 C.
They run fine for a short while, but not nearly as long.
Heat accelerates all aging processes. It's how they artificially age chips in order to calculate MTBF.
m4rtink 7 hours ago [-]
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.
DanHulton 5 hours ago [-]
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.
toephu2 3 hours ago [-]
> But it's never going to come close
never? I doubt that.
Technology will improve over time. Eventually I bet it will become cheaper.
Have you tried building in the U.S.? Why do you think it's so expensive to build in the U.S.? It's due to regulation and red tape.
unrented7977 2 hours ago [-]
Technology improves, but the laws of physics are constant and absolute (on human timescales).
Thermodynamics says no today, no tomorrow, and no 100 years from now. That's not ever going to change.
bagels 2 hours ago [-]
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.
asdff 5 hours ago [-]
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.
7e 3 hours ago [-]
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.
jryle70 1 hours ago [-]
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.
ForHackernews 4 hours ago [-]
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.
asdff 4 hours ago [-]
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.
scheme271 32 minutes ago [-]
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.
sunbum 3 hours ago [-]
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?
scottyah 2 hours ago [-]
> Sure datacenters with latency measured in several hours sure are useful
Training models takes weeks, are you really worried about a couple hours?
> Can be jammed by drone with laserpointer
Ok, you're just joking
alexnewman 4 hours ago [-]
But more and more Ukraine is using long range drones guided by SpaceX
ruszki 6 hours ago [-]
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?
xur17 5 hours ago [-]
> 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?
snovv_crash 5 hours ago [-]
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.
alexnewman 4 hours ago [-]
This has all been covered over and over again. It’s actually not that big of a deal
datadrivenangel 3 hours ago [-]
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.
scottyah 2 hours ago [-]
...but they are already building it.
rayiner 5 hours ago [-]
[flagged]
mike_ivanov 7 hours ago [-]
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.
lopsotronic 4 hours ago [-]
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.
hex4def6 1 hours ago [-]
Think you have an error -- it's t_hot / (t_hot - t_cold)
With those numbers, ideal carnot would be 500/(500-357) = 3.5.
Multi-stage could potentially get you to a COP of 2 or so. So 0.5MW.
ChickeNES 7 hours ago [-]
And if you look at SpaceX's Starmind sats, they will have a 160 m^2 liquid radiator for 175kw/250kw peak compute.
cyberax 5 hours ago [-]
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.
tristanj 5 hours ago [-]
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)
lopsotronic 5 hours ago [-]
ISS's two external cooling loops hold about 540 kg of ammonia combined, together they dump 70 kW.
cyberax 3 hours ago [-]
Of course. But their hot ends are nowhere near 220C. I don't think such heat pumps even exist right now except in labs.
So you'll need a lot of additional energy to run the pumps. Which will require additional radiator area.
spullara 4 hours ago [-]
Glad you are on the case before these companies foolishly waste their money sending datacenters to space.
foota 5 hours ago [-]
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?
JoeAltmaier 4 hours ago [-]
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.
AlotOfReading 3 hours ago [-]
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.
sgsjchs 3 hours ago [-]
It needs to be facing open space instead of other parts of itself, otherwise the radiation is just reabsorbed.
Forrest7778 6 hours ago [-]
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 :)
tintor 4 hours ago [-]
Is it possible for one side of panel to be used for solar power and other side for radiating heat?
jupp0r 5 hours ago [-]
Wouldn't this be solved like similar problems on earth by making small structures with large surface areas?
foota 5 hours ago [-]
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)
echoangle 2 hours ago [-]
You can use heatpumps to increase radiator temperature but then you need a heatpump and need to power it. But the principle is sound.
4 hours ago [-]
ww520 5 hours ago [-]
Don’t you get 4 faces to radiate away, assuming a long rectangular tube.
JackSlateur 7 hours ago [-]
It would be a shame if a rock came out of nowhere and hit that many square kilometers stucture
Luckily, there are almost no rock in space.
tantalor 5 hours ago [-]
Almost no rocks, but they're going 10 to 30 km/s
hyperhello 4 hours ago [-]
I assume the kilometer-size array would not be series-wired.
tessierashpool 7 hours ago [-]
there are two arguments for it.
one is marketing.
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.
nolok 7 hours ago [-]
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".
Ifkaluva 7 hours ago [-]
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.”
xnx 9 hours ago [-]
No solution, but that is the crux of the problem. They probably need to make a radiator that 1000x smaller and lighter.
> 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.
htrp 1 hours ago [-]
> 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.
Is it at least a 1:1 usage / cooling cycle?
725686 4 hours ago [-]
Can't they harness the heat to generate more electricity?
sterlind 4 hours ago [-]
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.)
iamgopal 3 hours ago [-]
How far are we from optical computing ?
dyauspitr 3 hours ago [-]
This is my only question.
tills13 4 hours ago [-]
Don't worry, they'll just ask Grok.
gmerc 8 hours ago [-]
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.
jryle70 54 minutes ago [-]
It's a scam when Elon does it.
It's Golden Dome when Google does it.
I guess it's something along the same line when Jeff Bezos does it. He does indeed plan it.
What is China's motive? why do they also need to pretend they want space data centers? [0], [1]
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.
JackSlateur 9 hours ago [-]
That's the neat part: you don't (ergo, this is yet another marketing crap)
scottyah 2 hours ago [-]
just like reusable rockets sending astronauts to the space station and internet in the sky. imagine if they delivered on those bs marketing claims?
Eisenstein 38 minutes ago [-]
I don't recall the scientific community declaring those things to have been BS when they were announced.
ElijahLynn 7 hours ago [-]
[flagged]
0cf8612b2e1e 7 hours ago [-]
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.
ChickeNES 7 hours ago [-]
> 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?
0cf8612b2e1e 7 hours ago [-]
We can wait for their profitability numbers, assuming it happens.
Regardless, those claim to have a maximum draw of 250kw. That’s one to two terrestrial data rack. Cute.
delusional 7 hours ago [-]
That guy is baffled we're not all driving around in cybertrucks talking to mecha-hitler. Why would i care?
GMoromisato 8 hours ago [-]
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.
0cf8612b2e1e 8 hours ago [-]
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.
GMoromisato 7 hours ago [-]
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.
motionlessveloc 5 hours ago [-]
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.
GMoromisato 5 hours ago [-]
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.
GMoromisato 2 hours ago [-]
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!"
sobellian 1 hours ago [-]
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."
cyberax 5 hours ago [-]
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!
Sorry. But this idea is fundamentally unworkable.
GMoromisato 5 hours ago [-]
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.
cyberax 4 hours ago [-]
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.
GMoromisato 2 hours ago [-]
Okay, so you admit it is possible. Cooling is not the problem. We're making progress.
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.
cyberax 1 hours ago [-]
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.
mzajc 8 hours ago [-]
> This is one of the easiest problems to solve. /../ All you need is a cheap way to launch mass to orbit.
So... not easy? I don't suppose we're at a point where you could reasonably send a large-enough radiator for a multi-gigawatt cluster into space?
m4rtink 7 hours ago [-]
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
GMoromisato 7 hours ago [-]
The plan is to launch thousands of 250 kW satellite. Doesn't sound insane at all.
GMoromisato 7 hours ago [-]
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.
devmor 7 hours ago [-]
> 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...
GMoromisato 6 hours ago [-]
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.
devmor 6 hours ago [-]
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.
GMoromisato 6 hours ago [-]
My point is you don't need fancy/expensive materials for your radiator. Anodized aluminum is at 0.8. With inexpensive coatings you can get to 0.9.
If your argument against space datacenters is "radiator materials are too expensive" then I just think that's not a very good argument.
devmor 3 hours ago [-]
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.
GMoromisato 2 hours ago [-]
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.
teaearlgraycold 7 hours ago [-]
It will never be cheaper to put compute into orbit. And costs for AI are dropping like a rock here on Earth.
GMoromisato 6 hours ago [-]
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.
teaearlgraycold 6 hours ago [-]
You’re right. Why am I wasting time on here?
GMoromisato 1 hours ago [-]
You're smarter than me on that point. I got sucked into the argument and ended up wasting a couple of hours. I'm an idiot.
legohead 7 hours ago [-]
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.
GMoromisato 6 hours ago [-]
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.
echoangle 2 hours ago [-]
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.
GMoromisato 1 hours ago [-]
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.
dekhn 5 hours ago [-]
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").
legohead 5 hours ago [-]
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.
GMoromisato 5 hours ago [-]
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.
tensor 2 hours ago [-]
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.
GMoromisato 1 hours ago [-]
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.
cyberax 5 hours ago [-]
> For SpaceX's 175 kW satellites
That's like a quarter of a rack of modern AI hardware. Modern AI datacenters are now in the multi-GW range.
GMoromisato 5 hours ago [-]
Okay, so you agree the cooling problem has a solution.
Now the argument is, what, you can't launch that many satellites?
echoangle 2 hours ago [-]
The argument is that launching and operating those satellites is more expensive than just using the same silicon on the ground.
GMoromisato 2 hours ago [-]
How sure are you of that? How much does each satellite cost? How much will silicon on the ground cost in 2030?
How can anyone be certain of any of those numbers without (a) knowing how the technology will evolve, and (b) doing the math?
I'm just astounded that people can have such confidence.
cyberax 1 hours ago [-]
We know such thing as physics and economics. That dictate the fundamental limits.
They are showing that space-based DCs only make sense for criminal enterprises. Which probably IS what's going on here.
scottyah 2 hours ago [-]
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.
Avicebron 7 hours ago [-]
Is Kessler syndrome priced into cost? Or is that just like, someone else's problem?
GMoromisato 10 hours ago [-]
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.
m4rtink 7 hours ago [-]
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.
Y-bar 7 hours ago [-]
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.
smw 1 hours ago [-]
This guy is obviously long SpaceX
maxlin 2 hours ago [-]
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.
gmerc 8 hours ago [-]
That's the fun part, they don't need to be viable. It's just the excuse to shovel tons of money to Trump donors, by rerunning the scam that was SDI.
And they never will be because it's always going to be cheaper to build them on the ground.
asdff 5 hours ago [-]
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.
7 hours ago [-]
ilamont 7 hours ago [-]
I didn't have time to watch the videos, but in the text I didn't see anything that addresses data center operations requiring manual intervention.
Swapping out obsolete or failing TPUs. Rewiring or replacing connections. "Listening" for sounds indicating an equipment failure.
What are the proposals to address these needs?
pennomi 7 hours ago [-]
Presumably the plan is to deorbit all failing or obsolete systems. It’s phenomenally wasteful.
ForHackernews 7 hours ago [-]
that's one way to skirt e-waste recycling requirements!
tintor 3 hours ago [-]
Launch spacewalk repair crew. Manned or robotics teleoperated.
trimethylpurine 7 hours ago [-]
The most obvious solution is to discard.
sghiassy 1 hours ago [-]
Why isn’t building data centers in Greenland being talked about?
- Unlimited geothermal energy.
- Cold climate for heat dissipation
- tons of land
old-gregg 2 hours ago [-]
I just searched for "Elysium" in comments. No hits. Perhaps it's too soon.
next_xibalba 41 minutes ago [-]
I have been saying for years that the great gap for ML is that it isn't in space. Glad Google finally caught up with me.
sanj 5 hours ago [-]
Does anyone understand the math behind this bit?
> In the right orbit, a solar panel can be up to 8 times more productive than on earth....
gwbas1c 5 hours ago [-]
Because the panel is positioned such that it's is always exposed to the sun.
1: There is no night or day.
2: There are no seasons.
3: There is no weather.
Basically, the primary motivating factor of putting AI in space is abundant solar energy. Otherwise, AI in space makes little to no economic sense.
pornel 2 hours ago [-]
But solar panels are dirt cheap. Just slap 8x more of them on earth.
It's nuts that it's supposed to be easier to send them to space than to truck them to a desert.
gwbas1c 1 hours ago [-]
I didn't mention the second compelling reason for data centers in space... All that requires land!
(But to be quite frank, I don't think data center is in space are going to be practical.)
mey 4 hours ago [-]
To build on the economic/practical issues.
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.
7e 4 hours ago [-]
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.
gwbas1c 1 hours ago [-]
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.
2 hours ago [-]
xnx 5 hours ago [-]
Hard to know, but there are some areas they are probably using:
* 24 hours of light vs. ~9 hours of light (e.g. winter)
* Panels perfectly perpendicular to sun 100% of the time vs. variable for fixed panels on earth
* No atmosphere
* No clouds
exe34 5 hours ago [-]
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.
Andrex 4 hours ago [-]
My layman expectation would have been much higher. It's got no atmosphere refracting anything and it's closer to the source of energy.
echoangle 2 hours ago [-]
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.
exe34 4 hours ago [-]
LEO isn't much closer to the sun, and the atmosphere probably doesn't absorb a huge amount at the wavelengths they work.
seydor 4 hours ago [-]
Aside from practical issues, why make your datacenters so vulnerable?
maxlin 2 hours ago [-]
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.
alexnewman 4 hours ago [-]
People want to put ai in space to hook them to sensors and predict . Checkout project Merlin
bar8uyr 2 hours ago [-]
Wait until they work out that earth is in space
drop_star 2 hours ago [-]
Google has a bridge to sell you
porridgeraisin 4 hours ago [-]
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.
But even in this comment stream there are tons of people saying the cooling problem is insurmountable.
zactato 9 hours ago [-]
I think one of the reasons for putting these in space is to move them beyond the borders of any national control.
GMoromisato 9 hours ago [-]
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.
m4rtink 7 hours ago [-]
Rocket Lab has launch pads in New Zealand.
ChickeNES 7 hours ago [-]
> (nor are they planning)
Not true
edot 8 hours ago [-]
Surely if this were the reason, you'd just put it in international waters?
tumdum_ 6 hours ago [-]
What does it matter where physically computers are located? If the owners can be imprisoned in US, the will cooperate with US government.
echoangle 2 hours ago [-]
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.
nova22033 5 hours ago [-]
You don't think Google has a self-interest in this? Google up how many shares of spacex are held by Alphabet.
folocitoan 2 hours ago [-]
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.
arcanemachiner 7 hours ago [-]
They should put data centers on the moon and call it Project Spaceshot.
hencq 7 hours ago [-]
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"
lastscattering 8 hours ago [-]
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likelybot 7 hours ago [-]
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ForHackernews 7 hours ago [-]
lowkey insane that it will end up cheaper to shoot your datacenter into space than get it past the county board permitting process.
airhangerf15 5 hours ago [-]
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.
onefiftymike 5 hours ago [-]
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.
I think dodging debris is challenging at that scale.
Also this is the solar cells not the radiators
https://www.youtube.com/watch?v=_qpdUNMt2yg
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.
1. https://www.reuters.com/business/finance/alphabets-spacex-be...
Didnt you answer your own question? Most would consider a 100x ROI more than sufficient for taking profits
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.
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.
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).
They run fine for a short while, but not nearly as long.
Heat accelerates all aging processes. It's how they artificially age chips in order to calculate MTBF.
For that you might need more advanced stuff like liquid droplet radiators (https://en.wikipedia.org/wiki/Liquid_droplet_radiator), heat sinks & pulsed operation. Still, it should be eventually doable.
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.
never? I doubt that.
Technology will improve over time. Eventually I bet it will become cheaper.
Have you tried building in the U.S.? Why do you think it's so expensive to build in the U.S.? It's due to regulation and red tape.
Thermodynamics says no today, no tomorrow, and no 100 years from now. That's not ever going to change.
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.
Training models takes weeks, are you really worried about a couple hours?
> Can be jammed by drone with laserpointer
Ok, you're just joking
We need > 2x more solar panels than we need radiators. Doesn't this imply radiation isn't really the limiting factor here?
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.
With those numbers, ideal carnot would be 500/(500-357) = 3.5.
Multi-stage could potentially get you to a COP of 2 or so. So 0.5MW.
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.
Other satellites have also used heat pumps, such as SES-17 in geostationary orbit https://www.esa.int/Applications/Connectivity_and_Secure_Com...
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)
Looks like some experimental pumps within this region have CoP around 30%: https://www.sciencedirect.com/science/article/abs/pii/S03605...
So you'll need a lot of additional energy to run the pumps. Which will require additional radiator area.
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)
Luckily, there are almost no rock in space.
one is marketing.
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.
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".
“ 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.”
TPU: 100,000+ watts/square-meter
Radiator: ~300 watts/square-meter
https://youtu.be/ktdbUIZKeSE?t=76
> 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.
Is it at least a 1:1 usage / cooling cycle?
(I guess you could try to capture the radiative photons via the photoelectric effect?? but I don't think it works.)
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.
It's Golden Dome when Google does it.
I guess it's something along the same line when Jeff Bezos does it. He does indeed plan it.
What is China's motive? why do they also need to pretend they want space data centers? [0], [1]
How about Europe's? [2]
[0] - https://www.tomshardware.com/tech-industry/space/china-puts-...
[1] - https://www.reuters.com/science/china-vows-develop-space-tou...
[2] - https://ascend-horizon.eu/data-centres-in-space/
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.
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.
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?
Regardless, those claim to have a maximum draw of 250kw. That’s one to two terrestrial data rack. Cute.
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.
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.
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.
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.
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.
[1] https://www.spacex.com/spacexai/starmind
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.
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!"
> 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."
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!
Sorry. But this idea is fundamentally unworkable.
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.
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.
Now your argument is that it's unprofitable. Here's the calculator: https://andrewmccalip.com/space-datacenters
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.
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.
So... not easy? I don't suppose we're at a point where you could reasonably send a large-enough radiator for a multi-gigawatt cluster into space?
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
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.
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.
The Thermal Control section on NASA's Small Spacecraft documentation center is quite an interesting read for this subject: https://www.nasa.gov/smallsat-institute/sst-soa/thermal-cont...
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...
The equation is:
Where P and T are the dominating factors. Don't worry about emissivity.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.
If your argument against space datacenters is "radiator materials are too expensive" then I just think that's not a very good argument.
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.
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:
Where 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.
People use that argument because it takes zero thought to make and significant effort to refute.
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.
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.
What's unfeasible about that? SpaceX has already launched 10,000 Starlink satellites. Falcon 9 launches 150 times per year.
That's like a quarter of a rack of modern AI hardware. Modern AI datacenters are now in the multi-GW range.
Now the argument is, what, you can't launch that many satellites?
How can anyone be certain of any of those numbers without (a) knowing how the technology will evolve, and (b) doing the math?
I'm just astounded that people can have such confidence.
They are showing that space-based DCs only make sense for criminal enterprises. Which probably IS what's going on here.
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.
And they never will be because it's always going to be cheaper to build them on the ground.
Swapping out obsolete or failing TPUs. Rewiring or replacing connections. "Listening" for sounds indicating an equipment failure.
What are the proposals to address these needs?
- Unlimited geothermal energy.
- Cold climate for heat dissipation
- tons of land
> In the right orbit, a solar panel can be up to 8 times more productive than on earth....
1: There is no night or day.
2: There are no seasons.
3: There is no weather.
Basically, the primary motivating factor of putting AI in space is abundant solar energy. Otherwise, AI in space makes little to no economic sense.
It's nuts that it's supposed to be easier to send them to space than to truck them to a desert.
(But to be quite frank, I don't think data center is in space are going to be practical.)
The useful life of cutting edge AI server hardware will require constant rotation of equipment to potentially remain competitive with more accessible solutions.
Heat management ( https://m.youtube.com/watch?v=-w6G7VEwNq0 )
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.
* 24 hours of light vs. ~9 hours of light (e.g. winter)
* Panels perfectly perpendicular to sun 100% of the time vs. variable for fixed panels on earth
* No atmosphere
* No clouds
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.
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.
It's just far out research experiment like another commented quoted from the text: https://news.ycombinator.com/item?id=49834746
But even in this comment stream there are tons of people saying the cooling problem is insurmountable.
However, I do think avoiding local control (state/city permits) is a reason for this.
Not true
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.
https://en.wikipedia.org/wiki/General_Motors_EV1
(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.
https://en.wikipedia.org/wiki/Space_Shuttle
https://en.wikipedia.org/wiki/McDonnell_Douglas_DC-X
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.
https://en.wikipedia.org/wiki/Teledesic
https://en.wikipedia.org/wiki/Iridium_Communications
https://en.wikipedia.org/wiki/Globalstar
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:
https://tinyurl.com/5aps6aam
It’s very confusing to have a project related to space called a moonshot project.