And just like that Elon Musk shifted the overton window away from "unthinkable" on yet another topic.

  It's physically impossible
  It's technically impossible
  It won't be profitable          <= You are here
  It's bad for the environment
  It needs to be nationalized

This is just a joke, obviously, but the debate over on ArsTechnica about Falcon 9 going away is all about how it needs to be nationalized.

I think one of the reasons for putting these in space is to move them beyond the borders of any national control.

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.

Did anyone at and point say it's technically impossible? There's been computers in space since the 60s after all.

It's just far out research experiment like another commented quoted from the text: https://news.ycombinator.com/item?id=49834746

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.

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.

How are they solving the heat dissipation issues?

That's the neat part: you don't (ergo, this is yet another marketing crap)

just like reusable rockets sending astronauts to the space station and internet in the sky. imagine if they delivered on those bs marketing claims?

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.

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.

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.

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.

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.

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.

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: 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?

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.

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.

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.

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.

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.

Other satellites have also used heat pumps, such as SES-17 in geostationary orbit https://www.esa.int/Applications/Connectivity_and_Secure_Com...

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.

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.

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.

Almost no rocks, but they're going 10 to 30 km/s

Wouldn't this be solved like similar problems on earth by making small structures with large surface areas?

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)

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?

It’s obvious that radiation isn’t the limiting factor, since, as you note, there’s no reason a satellite shouldn’t be able to radiate at least as fast as it gets power from the sun. I don’t know how this became a meme.

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.

This has all been covered over and over again. It’s actually not that big of a deal

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.

...but they are already building it.

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.

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).

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.

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.

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.

Okay, so you admit it is possible. Cooling is not the problem. We're making progress.

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.

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!"

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?

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

It will never be cheaper to put compute into orbit. And costs for AI are dropping like a rock here on Earth.

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.

You’re right. Why am I wasting time on here?

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.

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...

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.

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.

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 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.

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.

Okay, so you agree the cooling problem has a solution.

Now the argument is, what, you can't launch that many satellites?

The argument is that launching and operating those satellites is more expensive than just using the same silicon on the ground.

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.

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 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.

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.

The article mentions that:

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.

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.”

Can't they harness the heat to generate more electricity?

lowkey insane that it will end up cheaper to shoot your datacenter into space than get it past the county board permitting process.

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.

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?

Presumably the plan is to deorbit all failing or obsolete systems. It’s phenomenally wasteful.

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.

A foreign nation shooting down a US satellite would be an act of war, regardless of whether it's a Google or CIA satellite.

but 'accidentally' bumping it with space debris would be an 'accident'.

Well, then American will "accidentally" shoot down their satellites. Nobody wants any of that.

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.

Some people, or physics?

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.

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?

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)

I don’t see how America or Google remain relevant unless SpaceX succeeds .

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.

1. https://www.reuters.com/business/finance/alphabets-spacex-be...

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

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....

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.

My layman expectation would have been much higher. It's got no atmosphere refracting anything and it's closer to the source of energy.

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.

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.

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.

Aside from practical issues, why make your datacenters so vulnerable?

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.

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

“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

Presumably that’s not a single satellite.

I wonder if the shadows from such a large area would have a climate cooling effect?

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.

How can this practically work though? As Earth goes around the Sun 90 degrees, orbit will become half-shadowed.

The earth isn't exactly round, you can use this to process your orbit exactly 360deg/year so you can always stay in the sun. https://en.wikipedia.org/wiki/Sun-synchronous_orbit

Desert land is full of that amount of area available for peanuts.

That’s 4000 acres. I see a 6000 acre ranch available in Arizona for $7m. The cost of building a 5GW DC is about 100 billion. Land including enough for all the solar and battery you need to be completely self sufficient is basically free.

That whitepaper puts the cost of a 40 MW cluster at $167m on land and $8.2m in space, inclusive of launch costs.

that sounds ridiculous. How could it be so much cheaper

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.

At planet we didn't have any radiation shielding. Why would spacex need it?

On the planet we have tremendous radiation shielding. The van allen belt and the atmosphere, to start with.

They're assuming $30/kg launch costs.

how much area do you need to radiate away 40 MW, assuming you want to keep your GPUs at a toasty 90 celcius. Every space datacenter fan/promoter enthuses about the free solar power, but forget to mention how the heat will be dissipated.

Starcloud seems like a whole lot of hand waving and BS. This is a good video that goes over their problems:

https://www.youtube.com/watch?v=_qpdUNMt2yg

What happens to all the precious metals that go up with these data centers? At least with a land based data center we have a vague hope of recycling the raw materials at some point in the future.

Google has a bridge to sell you

Why isn’t building data centers in Greenland being talked about?

- Unlimited geothermal energy.

- Cold climate for heat dissipation

- tons of land

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.

You still need hundreds of tonnes of rocket fuel no matter what, though.

Back of the napkin math says a bare minimum of ~2000kg of solid fuel in three stages to “get to” GEO using a 3-stage rocket, to deliver 1kg of “something.” You’d need a gravity assist highly elliptical orbit which is a touch harder to pull off (but probably not harder than getting 2000kg of ammonium perchlorate). Plus building the actual rocket, guidance computer, etc.

Not trivial but not impossible. If you’ve got a few hundred million people with nothing better to do, I’m sure a few dozen/hundred could pull it off.

Businesses run anywhere real money can be made. Middle east is the most volatile place. Yet, the businesses are perfectly okay building infrastructure to extract, refine and ship oil from there.

If real money can be made, there is no need of datacenters in space. Offer some country some money and they'll let you build whatever you want. The whole idea is entirely unprofitable thats why they are making up things that won't work economically. Keep giving us money indefinitely, we'll keep spending, money can be made after a few decades of spending ... trust us.

Note that you didn't mention any such country, and for good reason - there is none.

You'd need a dictatorship where people's voices don't matter, but then there's no right of ownership either.

You'd need a dictatorship where people's voices don't matter, but then there's no right of ownership either.

And there are plenty of those countries. As well as countries that aren't dictatorships. Every leader everywhere is available for sale. In democracies, usually for a small sum. Dictatorships ask for a percentage of profit.

Everyone knows how the current administration got to power: https://edition.cnn.com/2025/02/01/politics/elon-musk-2024-e...

Trump will gladly allow datacenters to be built on federal lands. Just like he allows Oil/Coal and bans Wind and Solar. The only reason there is new story of Space Datacenters is because even if they are given everything by the Govt, it simply won't work.

If you see a datacenter in orbit, it means something went wrong on Earth: https://systemsthinkingcollection.substack.com/p/space-datac...

People believe all kinds of fiction and garbage, like going to Mars. (Why Terraform Mars When We Can Fix The Earth? https://www.youtube.com/shorts/8mhib97--n4)

The same argument holds for AI DCs. If you can build profitable AI datacenters in space, why can't you build profitable AI datacenters on Earth? The only reason is you can't build profitable AI datacenters on earth. Just give us a few more trillions and wait a decade or two, we promise ...

This idea that space is a way to get out of the reach of NIMBYs is so dumb.

a: now you’re in everyone’s back yard, since satellites in orbit can be seen by the naked eye at twilight zipping across the sky, so now the whole earth hates you

b: you are still launching from earth, which is a pretty significant target if you’re worried about ecoterrorism.

I'm curious why a space data center has to orbit Earth. Why not a solar orbit? Batched work can be done anywhere if you can tolerate the latency.

It can go further if you want it to be even more expensive, sure.

b: you are still launching from earth, which is a pretty significant target if you’re worried about ecoterrorism.

This so much. Good luck destroying a DC on earth without a very strong force. On the other hand, destroying a rocket on its launchpad just take one FPV drone.

Note that you didn't mention any such country, and for good reason - there is none.

All flavors of Govt (authoritarian/democratic) are bending over backwards to build new DCs.

In Ulanqab, China buildout of data centers 1000x size of Colossus: https://x.com/RnaudBertrand/status/2099319829589295197

India, a country which has neither power nor water or any measurable infrastructure is giving massive subsidies to hyperscalers to build AI DCs. They get free land (very very costly), nearly free energy, guaranteed supply of water and so on ...

Examples of one authoritarian govt and one democratic govt. And there are 180+ other countries.

just to add a few more reasons not mentioned on X why they chose this place:

Cooling is a major factor. Ulanqab's average temperature is about 4.3°C, enabling free air cooling nearly 10 months a year and very low PUE around 1.1.

Even more decisive is cheap, abundant power—largely wind and solar plus coal—at roughly half the price of eastern China. Add vast open land, dedicated low-latency fiber to Beijing (~2-5 ms),

The real point is power limitations, putting stuff in space in the right orbit lets you turn solar power into reliable base load.

Why stop somewhere in between? You can go straight to the Sun and directly tap into near infinite source of energy. No need of solar panels, direct access to thermonuclear energy, too cheap to meter. The economics already works out, zero capex, zero opex for the next ~4 billion years. Just needs a few small problems to be worked out, like a pipe to transfer energy.

I guess we'll see if their idea warrants your ludicrous comparison soon. Google is putting out a lot of real resources to test theirs out, so presumably it wasn't obviously insane to them when they ran the numbers.

I do not presume that. Plenty of projects that happen don't actually make economic sense.

That's usually in hindsight? And I said it wasn't obviously insane to them, not that it would pencil out in the end.

Can also just be an asymmetric bet - relatively small outlay with low chance of working, but massive upside if it does, such that it's still positive expected value.

But mostly, I think all these armchair quarterbacks should not have very strong opinions about something that they almost certainly don't know much about compared to the people who build these. The person I responded to cited a random blog that ran some numbers, and includes such gems as "In space, a broken fan or a fried motherboard is a crisis." Just... lol

The problem with space is that you need to radiate all that waste heat.

There is no evidence that AI will increase unemployment.

This is what AI was fucking promoted as being for! The utopia where machines do all our work and we receive universal basic income to enjoy our freedoms.

Taking away work was exactly the premise it was sold under.

This is what AI was fucking promoted as being for! The utopia where machines do all our work and we receive universal basic income to enjoy our freedoms.

No one promised any utopia of any sort. The only promise was that AI would put people out of work. The rest is just some naive Star Trek bullshit that was never on the table.

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).

So are container ships in international waters. Put them there.

Curious what specific problem this solves that can't be done terrestrially. Bandwidth and latency from orbit sound gnarly.

It truely amazes me how much smarter sceptical posters on hackernews are vs google, spacex , china and the whole space industry.

Really, even google saying they are considering doing some thing like this?

Maybe you only discount the idea because “Elon”?

What no one seems to be asking is what privacy and legal laws still apply for a datacenter in orbit?

They're effectively outside the sovereignty of any country. Further, it would be extremely impractical for any government's law enforcement to raid the datacenter and confiscate the servers.