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I would not assume cooling has been worked out.

Space is a vacuum. i.e. The lack-of-a-thing that makes a thermos great at keeping your drink hot. A satellite is, if nothing else, a fantastic thermos. A data center in space would necessarily rely completely on cooling by radiation, unlike a terrestrial data center that can make use of convection and conduction. You can't just pipe heat out into the atmosphere or build a heat exchanger. You can't exchange heat with vacuum. You can only radiate heat into it.

Heat is going to limit the compute that can be done in a satellite data centre and radiative cooling solutions are going to massively increase weight. It makes far more sense to build data centers in the arctic.

Musk is up to something here. This could be another hyperloop (i.e. A distracting promise meant to sabotage competition). It could be a legal dodge. It could be a power grab. What it will not be is a useful source of computing power. Anyone who takes this venture seriously is probably going to be burned.

The really crazy thing is you don't need to know more then basic (non Hollywood) physics to know how dump this is

1. every gram you need to send to space is costly, a issue you don't have at ground level

2. cooling is a catastrophe, sure space is cold, but also a vacuum, so the cooling rate is roughly the infrared radiation rate. This means if you are not careful with the surface of a satellite it can end up being very slowly cooked by sunlight alone not including running any higher heat producing component (as it absorbs more heat from sunlight then it emits, there is a reason satellites are mostly white, silver or reflective gold in color). Sure better surface materials fix that, but not to a point where you would want to run any heavy compute on it.

3. zero repair-ability, most long running satellites have a lot of redundancy. Also at least if you are bulk buying Nvidea GPGPUs on single digit Million Euro basis it's not rare that 30% have some level of defect. Not necessary "fully broken" but "performs less good then it should/compared to other units" kind of broken.

4. radiation/solar wind protections are a huge problem. Heck even if you run things on earth it's a problem as long as your operations scale is large enough. In space things are magnitudes worse.

5. every rocket lunch causes atmospheric damage, so does every satellite evaporating on re-entry. That wasn't that relevant in the past, but might become a problem just for keeping stuff like Starlink running. We don't need to make it worse by putting datacenters into space.

6. Kessler Syndrom is real and could seriously hurt humanity as a whole, no reason to make it much more likely by putting things into space which don't need to go there.

Last but not least, wtf would you even want to do it?

There is zero benefit, non nada.

I was talking to someone about this the other day. I was part of a team at NASA that developed a cooling system for the ISS and this whole premise makes no sense to me.

1. Getting things to space is incredibly expensive

2. Ingress/egress are almost always a major bottleneck - how is bandwidth cheaper in space?

3. Chips must be “Rad-hard” - that is do more error correcting from ionizing radiation - there were entire teams at NASA dedicated to special hardware for this.

4. Gravity and atmospheric pressure actually do wonders for easy cooling. Heat is not dissipated in space like we are all used to and you must burn additional energy trying to move the heat generated away from source.

5. Energy production will be cheaper from earth due to mass manufacturing of necessary components in energy systems - space energy systems need novel technology where economies of scale are lost.

Would love for someone to make the case for why it actually makes total sense, because it’s really hard to see for me!

I'm convinced that >30% of this comes from ideas leaking out of fiction such as like Neuromancer, and percolating through the minds of wealthy people attracted to some of the concepts. Namely, the dream of being a hyper-wealthy dynasty, above any earthly government, controlling an extraterritorial Las Vegas Fiefdom In Space. (Which in the book, also hosted a powerful AI.)

Then they work backwards, trying to figure out some economic engine to make it happen. "Data centers" are (A) in-vogue for investment right now and (B) vaguely plausible, at least compared to having a space-casino.

The crux of it is that radiative cooling in space is dependent on exposed surface, not total surface area like a radiator or heatsink on earth - this means if you just put an existing finned heatsink in space it would radiate most of it's heat back to itself - the only net cooling you'd have is the amount that can radiate outwards without hitting itself.

For a benchmark - the IIS uses about 4500sqft (420 sqm) of radiators just to keep it's onboard equipment (~70KW) cooled. That's ~150-200 W/sqm.

That means, per GPU, you'd need about 2.5-3.0 sqm of passive radiators.

For a 1MW satellite (~8 datacenter racks of GB200/NVL72) you'd need basically half a football field of bleeding-edge solar panels (that also need to radiate their heat on the reverse side) and a similar sized cooling array of heat radiators for the electronics.

This is on the scale of 40-50 tons - about 10% of the IIS. This should fit on falcon heavy or starship - assuming the solar array and radiators can fold up to fit inside. You could, purely based on weight, launch 2 of these per starship launch.

If you consider the Opex savings (electricity, rent, facilities maintenance) and putting 2 of these on a single starship launch, I still think the ROI would be too long. You're saving about ~$1M per year in Opex but it's costing you $25M to launch it into space and likely an extra ~$50M in satellite equipment (based on starlink satellite costs) on top of the compute. Will those GPUs still be useful in 10 years? Probably not.

I don't think the math is there that justifies the free electricity - even at gigawatt scale (thousands of satellites mass-produced) and at a dramatically lower cost per satellite and per launch. Getting costs down on this would involve tightly integrating the compute and the satellite hardware which would make upgrading the compute independently from the cooling/power infrastructure in the future a significant challenge.

Data centers in space may or may not make sense (personally I'm quite skeptical) but the objections in the article certainly don't make sense.

1. The only reason there are 15,000 satellites in space is because SpaceX launched about 9,500 of them (Starlink is 65% of all satellites) on their semi-reusable Falcon 9. If fully-reusable Starship pans out, they will be launching satellites at 10x the rate of Falcon 9 at the very least.

2. You don't need to upgrade the satellites, you just launch new ones. The reason data center companies upgrade their servers is because they can't just build a new data center to hold the new chips. But satellites in space are a sunk cost, so just keep using the existing satellites while also launching new ones.

3. Falling solar panel costs decreases the power costs for both earth-based and space-based, but they're more efficient in space so the benefit would be proportionally greater there.

As I said, I'm skeptical too, but let's be skeptical for good reasons.

As the focus here is solely on the US, and the comments focus too much on the impossibility of heat dissipation, I want to include some information to broaden the perspective.

- In the EU, the ASCEND study conducted in 2024 by Thales Alenia Space found that data center in space could be possible by 2035. Data center in space could contribute to the EU's Net-Zero goal by 2050 [1]

- heat dissipation could be greatly enhanced with micro droplet technology, and thereby reducing the required radiator surface area by the factor of 5-10

- data center in space could provide advantages for processing space data, instead of sending them all to earth. - the Lonestar project proved that data storage and edge processing in space (moon, cislunar) is possible.

- A hybrid architecture could dramatically change the heat budget: + optical connections reduce heat + photonic chips (Lightmatter and Q.ANT) + processing-in-memory might reduce energy requirement by 10-50 times

I think the hybrid architecture could provide decisive advantages, especially when designed for AI inference workloads,

[1] https://ascend-horizon.eu/

Very confused by this plan. Data centers on Earth are struggling with how to get rid of waste heat. It's really, really hard to get rid of waste heat in space. That seems to be about the worst possible place to put a data center.

Surely, the question is: how big do the radiators have to be?

gemini says that the NVIDIA DGX H100 is 130kg and takes 11kW.

It says space-based radiators in the 100kW range are approx 15kg per kW. And space-based solar panels are approx 1kg per kW.

So let's says we're talking about 1 system that bundles 9 DGX H100's. That's 1.2T for the computing system, 1.5T for the radiator, 100kg for the solar panels, and let's say 2T for the propulsion, propellant, guidance, and all the other spacecraft stuff. That's a total of about 5T, and the radiator is just about 20% of the mass budget.

The power radiated is proportional to the 4th power of the temperature, so they would be incentivized to develop a heat exchanger with a high temperature working fluid.

You guys clearly didn't read the full blog post where Musk mentions lunar mining. They're going to put an ASML machine on the moon and turns regolith into chips and solar panels automatically. Literally free compute

The thing I find most notable is the lack of any concrete information on how these things are to be cooled, other than quotes like "space cooling is free".

If you want to radiate away the heat, you are either limited by the Stefan-Boltzmann equation which requires extraordinarily large radiators at any reasonable operating temperature, or have to develop a "super-Planckian" radiator technology, something which while it may be theoretically possible doesn't seem to actually exist yet as a practical technology.

The only other plausible technology I can think of would be to use evaporative or sublimation-based cooling, but that would consume vast quantities of mass in the process, every bit of which would have to be delivered to space first.

Has anyone seen any published work that suggests it is actually anywhere near economically feasible to dissipate megawatts of power in space, using either these or any other technology?

As a thought experiment, if humanity wanted to go all in on trying to move industrial processes and data centers off planet, would it make more sense to do so on the moon?

The moon has:

- Some water

- Some materials that can be used to manufacture crude things (like heat sinks?)

- a ton of area to brute force the heat sink problem

- a surface to burry the data centers under to solve the radiation problem

- close enough to earth that remote controlled semi-automated robots work

I think this would only work if some powerful entity wanted to commit to a hyper-scale effort.

As far as I can tell, Data centres in space only seem viable because their advocates insist on comparing them to standard terrestrial data centres.

And nobody ever calls them out on it.

Today's data centres are optimised for reliability, redundancy, density, repairability, connectivity and latency. Most of advertised savings come not from placing the data centre in space, but the fact that advocates have argued away the need for absolutely everything that modern data centres are designed to supply, except for the compute.

If they can really build a space data centre satellite for as cheap as they claim, why launch it? Just drive it out into the middle of the desert and dump it there. It can access the internet via starlink, and already has solar panels for power and radiators for cooling. IMO, If it can cool itself in direct sunlight in space, it can cool itself in the desert.

The main thing that space gains you over setting up the same satellite in the desert is ~23 hours of power, vs the ~12 hours of power on the ground. And you suddenly gain the ability to repair the satellite. The cost of the launch would have to be extremely cheap before the extra 11ish hours of runtime per day outweighed the cost of a launch; Just build twice as many "ground satellites".

And that's with a space optimised design. We can gain even more cost savings by designing proper distributed datacenter elements. You don't need lightweight materials, just use steel. You can get rid of the large radiators and become more reliant on air cooling. You can built each element bigger, because you don't have to fit the rocket dimensions. You could even add a wind turbine, so your daily runtime isn't dependant on daylight hours. Might even be worth getting rid of solar and optimising for wind power instead.

An actual ground optimised design should be able to deliver the same functionality as the space data centre, for much cheaper costs. And it's this ground optimised distributed design that space data centres should be compared to, not today's datacenter which are hyper-optimised for pre-AI use cases.

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Space data centres are nothing more than a cool Sci-Fi solution looking for a problem. There have been mumblings for years, but they were never viable (even bitcoin mining was a bit too latency sensitive). Space data centre advocates have been handed a massive win with this recent AI boom, it's the perfect problem for their favourite solution to solve.

But because it's a solution looking for a problem, they are completely blind to other solutions that might be an even better fit.

As long as we're pointing out things that don't make sense: A long time ago in the United States we decided to run electricity _everywhere_, even farmhouses in the middle of nowhere. The solution to broadband in the United States is somehow, inexplicably "Let's use satellites" rather than increase tower coverage or run hard lines. It is a _terrible_ solution to this problem based on the cost alone.

This sentence proves the author has no ability for logical thinking: Data centers in space only make sense if they are cost effective relative to normal data centers.

I too don't think it's currently a sensible solution. But the author completely unable to make a proper case. For instance, just to refute that one claim, there are many reasons to do it in space even at an cost.

Space-based data centers provide an off-world backup that is immune to Earth-specific disasters like earthquakes, floods, fires, or grid collapses. Servers in orbit are physically isolated from terrestrial threats, making them safe from riots, local warfare, or physical break-ins.

Moving infrastructure to space solves local community disputes by removing the strain on residential power grids and freeing up land for housing or nature. Space data centers do not deplete Earth’s freshwater supply for cooling, unlike terrestrial centers which consume billions of gallons annually.

Solar panels in orbit can access high-intensity sunlight 24 hours a day without interference from clouds, night, or the atmosphere.

Data stored in space can exist outside of national borders, protecting it from seizure, censorship, or the legal jurisdiction of unstable governments. Data transmission can be faster in space because light travels roughly 30% faster in a vacuum than it does through fiber optic cables.

Processing data directly in orbit is necessary for satellites and future space stations to avoid the delay and cost of beaming raw data back to Earth

To Steelman the topic, Musk’s whole alleged mission is to make humans a multi-planet species that can survive an earth killing event.

To that end, a small data center space isn’t about unit-economics, it’s a bigger mission. So the question we should consider is what can we put into space the further that mission. Can we put a meaningful sum of human knowledge out there for preservation? It sounds like “yes,” even if we can’t train ChatGPT models out there yet.

AI data-centers use upwards of 100MW. The biggest solar panels in space could produce around 240KW. When they speak of AI data-centers in space what do they actually mean in realistic non theoretical terms and where are the materials for this coming from?

If the AI data-center used only 10MW then each could have two redundant SMR's assuming the cooling challenges have been worked out but then we could have nuclear reactor disposal and collision issues.

It seems like every argument in favor of doing this is: "yeah sure but what if X was Y% cheaper?"

And some of us are reading these things and trying to be polite.

But at some point patience runs thin and the only response that breaks through the irrationality is some variation of "what if unicorns and centaurs had teamed up with Sauron?"

The limit of the ratio of useful:useless "what if's" approaches zero.

The Kessler syndrome is mentioned, satellites colliding, causing a cascade of follow-up collisions. This gets brought up a lot, but people have a poor intuition on how large the orbit space is. Think of it this way: It's obviously larger that Earth's surface, and placing, say, a million objects on Earth still leaves a lot of space between them (there are thousands as many humans). Yes, satellites move in certain orbits, not in random places, but space is large, and humans are bad with imagining large numbers and things. The illustrations with fat dots on tiny earth images are misleading too IMO.

Apart of that, I do agree that space data centers are probably just a marketing stunt at this point, although some things could obviously be done to increase their chances, like more lightweight designs on GPUs, something that was never a big topic before.

One way to work around the heat dissipation issues in space (and also on earth) is to move to computing systems that operate entirely at cryogenic temperatures to take advantage of superconducting circuitry.

I've heard stories that over a decade ago teams inside hyperscalars had calculated that running completely cryogenically cooled data centers would be vastly cheaper than what we do now due to savings on resistive losses and the cost of eliminating waste heat. You don't have to get rid of heat that you don't generate in the first place.

The issue is that at the moment there are very few IC components and processes that have been engineered to run at cryogenic temperatures. Replicating the entirety of the existing data center stack for cryogenic temps is nowhere near reality.

That said, once you have cryogenic superconducting integrated circuits you could colocate your data centers and your propellant/oxidizer depots. Not exactly "data centers off in deep space" since propoxd tend to be the highest traffic areas.

They're gonna propose something dumb like ejecting coolant out into space as a disposable heatsink and then they're gonna spend a bunch of money trying to build a proof-of-concept but it will never go anywhere because it's really some kinda money laundering scheme or whatever the Hyperloop nonsense was.

As others point out this is a bad idea.

Asside from the other excellent comments on power consumption, cooling and radiation. One point I didn't see being made in the comments much is maintenance costs.

Now I don't find myself in the facility of a data center often in daily life, however I do know that medium to big data centers require 24/7 hardware replacement. I believe this is what those 5 guys with the bikes and scooters are doing in every data center. That would be very difficult, near impossible in space (with the current space fairing infrastructure).

How about we just make a giant heatsink that reaches into space instead. Then we can cool the whole planet. Coming up with crazy ideas is cheap, but the logistics are obviously impractical.

I think what many people miss is that energy became far less location dependent if you put compute next to its generation. The latency for token generation is not so important. So the ratios between energy consumed, bandwidth and latency would in theory favour building dark token factories in remote but optimal locations. But i guess construction and logistics are an issue.

It possibly makes sense if you're preparing for war, harder to hit, harder to physically break into, beyond the range of nuclear EMP, and accessible from anywhere on earth.

There are two very distinct kinds of AI workloads that go into data centres:

    1. Inference
    2. Training

Inference just might be doable in space because it is "embarrassingly parallel" and can be deployed as a swarm of thousands of satellites, each carrying the equivalent of a single compute node with 8x GPUs. The inputs and outputs are just text, which is low bandwidth. The model parameters only need to be uploaded a few times a year, if that. Not much storage is required , just a bit of flash for the model, caching, logging, and the like. This is very similar to a Starlink satellites, just with bigger solar panels and some additional radiative cooling. Realistically, a spacecraft like this would use inference-optimised chips, not power-hungry general purpose NVIDIA GPUs, LPDDR5 instead of HBM, etc...

Training is a whole other ballgame. It is parallelisable, sure, but only through heroic efforts involving fantastically expensive network switches with petabits of aggregated bandwidth. It also needs more general-purpose GPUs, access to petabytes of data, etc. The name of the game here is to bring a hundred thousand or more GPUs into close proximity and connect them with a terabit or more per GPU to exchange data. This cannot be put into orbit with any near-future technologies! It would be a giant satellite with square kilometers of solar and cooling panels. It would certainly get hit sooner or later by space debris, not to mention the hazard it poses to other satellites.

The problem with putting inference-only into space is that training still needs to go somewhere, and current AI data centres are pulling double-duty: they're usable for both training and inference, or any mix of the two. The greatest challenge is that a training bleeding edge model needs the biggest possible clusters (approaching a million GPUs!) in one place, and that is the problem -- few places in the world can provide the ~gigawatt of power to light up something that big. Again, the problem here is that training workloads can't be spread out.

Space solves the "wrong" problem! We can distribute inference to thousands of datacentre locations here on Earth, each needs just hundreds of kilowatts. That's no problem.

It's the giaaaant clusters everyone is trying to build that are the problem.

I'm sorry I really don't understand this. I have a computer. I put it in a warehouse. You have a computer, you shoot it into space. What problem have you solved?

Is this all an effort to utilize more efficient solar panels? Are solar panels really the limiting factor for data centres?

We really need to stop letting Musk and others just put what ever they want in space we are getting close to the Kessler limit and that could be very very bad if it happens. They have some ideas but this is already and issue, China had an issue after a launch were debris hit the capsule breaking it forcing them to send a second capsule.

https://climatecosmos.com/sustainability/how-close-are-we-to...

It's a scam for investors.

The self-driving car worked too well. Tesla is promising that for over a decade now, and still can't deliver. They came much closer to the goal, but are still very far away from it. Shareholders don't seem to care.

Admiral Grace Hopper is famous for using a length of wire to explain to others what a nanosecond was.

https://www.pbs.org/newshour/world/pentagon-embraces-musks-g...

Data centers in space make absolute sense when you want as close to real time analysis on all sorts of information. Would you rather have it make the round trip, via satellite to the states? Or are you going to build these things on the ground near a battlefield?

Musk is selling a vision for a MASSIVE government contract to provide a service that no one else could hope to achieve. This is one of those projects where he can run up the budget and operating costs like Boeing, Northrup etc, because it has massive military applications.

By combining ai with space, in addition to any other plays that he might be playing around legal or financial areas, he's positioning (marketing) spaceX for the bandwagon that everyone else might jump into to deploy a space datacentre. He's providing the medium (spacex rockets) to realise this potentially unfeasible idea. He makes additional money that way - to then create a new type of money-making fuel after that. HN audience might be calculative - but the rest of the population is far less so.

This might also be a new vehicle to mask any space warfare technology deployments.

There are plenty of legit concerns here about e.g. the launch externalities which are actually greater than the launch costs themselves, i.e. climate impact to future generations.

However one flaw in this critique is that is only looks at the cost of ground-based solar panels and not their overall scalability. That is, manufacturing cost is far from the only factor. There is also the need for real estate in areas with good sun exposure that also have sufficient fresh water supply for cleaning.

When we really consider the challenges of deploying orders of magnitude more terrestrial solar, it really requires a more detailed and specific critique of the orbital vision. Positive includes near continuous solar exposure (in certain orbits) and no water requirements.

Much has been said of cooling but remember, there is a lot of literal space between the satellites for radiative cooling fins. It is envisioned they would network via optical links, and each mini satellite would be roughly on the order of a desktop GPU (not a whole data center rack). The vision is predicated on leveraging a ton of space for lots of mini satellites on the order of a Dell desktop tower. The terrestrial areas that are really cold are also not that great for solar exposure.

Personally I don't know how it will play out but the core concern I have about making these kinds of absolutist predictions is they make weak assumptions about the sustainable scalability of terrestrial power. And that is definitely the case here in that it only looks at the manufacturing cost of solar.

I get it. This is a scam. The discussion is not about what you think it is. (EDIT: Or not, I don't care.)

BUT the fact that we are even arguing about whether or not we should be putting data centers into space is so incredibly absurd to someone who watched the Challenger explode and assumed that space wouldn't be ventured into again in my lifetime.

People don't realize how much the priors have changed. Take a minute to appreciate that. We are living in a world where people are debating if it makes sense to spend a bazillion dollars to put a hard disk into orbit.

I wonder if the Klingons are good at cyber warfare.

The author seems to have confused a few things.

* They assume 1 satalite = 1 GPU. This is quite funny, actually. A single H200 floating in space with a solar panel and an antenna. In reality, a satellite would pack as many chips as the heat/power allows. A Starlink-sized satellite should be able to hold 40 or so chips. There's no reason why a larger satellitte couldn't hold, say, 1024. * They mention training, but sampling is what makes sense here. Training is a different beast, and requires high reliability, high bandwidth, low latency, and a lot of IO. Space would not be ideal for this. I'd expect training to remain terrestrial and just do sampling in space. (FWIW, sampling will be most of the compute allocation). * Also, no one upgrades GPUs in datacenters, they just add new nodes and leave the old ones there. Google still has their P100 nodes running. Not being able to fix them, though, is a significant concern.

This being a forum full of engineers, it is not surprising that everyone concentrates on the technical challenges thereof. But that may be a distraction.

I suspect that Musk wants to build space data centers in order to mitigate political and societal problems, which may yet prove more intractable than cooling in space.

The current expansion of terrestrial data centers has already caused a huge backlash. Their adversaries may well try to regulate them out of existence, at least locally. If an important jurisdiction like California or Germany subjects building of new data centers to regulations similar to building, say, a new nuclear power station, they will achieve a de-facto stop on further development there even without banning them outright.

Space, while not entirely lawless, is much harder to regulate this way. Local authorities have no power over it, nor do governments of nations without space capabilities. Big authorities of big nations (the FAA etc.) do, but they will likely be more friendly to already established launch businesses like SpaceX, not least because of the geopolitical dimensions of having a vibrant space sector.

From Musk's POV, this may be worth the additional cost and technical troubles.

It makes sense if you want low-latency compute accessible to other things in space making use of it: Pharmaceutical research, manufacturing. These are large, non speculative areas of likely growth in the space industry. Manufacturing especially will require lots of inference compute with the AI systems currently under development for industrial robotics.

If you're looking at this and saying "Lol, no, we don't need data centers in space just to power more GPT sycophancy and some health insurance company's RAG workflows." Then you're right, so just move on from that usage and consider the things we'd like to do in space, and especially the things we're already doing but want to do more of.

I know, my gut was telling me this is ridiculous, premature at best even through the lens of expanding space industry. But then with respect to the need for data centers-- had I even thought about it a year ago, my gut would have laughed if someone had said "Buy Wester Digital, HDD's are a growth stock".

This is written by someone that is not in aerospace that thinks terrestrially.

Engineering is always a question of tradeoffs.

Launch costs are dropping, and we’re still using inefficient rockets. Space elevators & space trains, among others, can drop this much more, the launch costs are still dropping, even using rockets, maybe we’ll never get to elevators & trains the costs will drop so low!

Radiation shielding is not required for VLEO or LEO, and phenomenally more capable aerospace processors are near - hi Microchip Inc! There are many other radiation solutions coming, no doubt with nuclear power.

Satellites can be upgraded at scale, though for many things, it does not make $ sense to upgrade them, but fuel , reaction wheels, solar panels, among other things do make $ sense to replace.

Latency was technically solved in 1995 & 2001 with the first laser comms missions NASDA’s ETS-VI kiku-6 and ESA’s Artemis , and Laser crossbars for comms are common. A full laser TDRS no RF is not yet extant but soon. Earth to deepspace was just demonstrated by ESA.

Cooling can be significantly improved due to lower launch costs, heat piping, RTGs, TEGs, and thermoradiative cells, not to mention sunside solar and darkside inline radiators

Furthermore, it is very likely that as neuromorphics with superior SWaP emerge, we could see very different models of space based computation.

Economic tradeoffs should drive many of these decisions as I’m not discussing the other applications of datacenter in space

Data centers in space make no sense because cooling things in space is insanely hard!

Yeah, space is cold, but also you don't have access to large thermal masses with which to exchange heat, so the fact that space is cold does not help much.

In space the only option for cooling is large radiators. If you had a data center in space you'd need enormous radiators -- much larger than the data center itself.

(On Earth we can exchange heat with the environment, and the environment includes convection and the water cycle and ultimately can expel excess heat via high altitude condensation of water vapor where most of the heat released escapes to space. As well clouds can both block insolation as well as keep heat below trapped, but altogether between high altitude condensation and blocking insolation this is the mechanism by which Earth keeps its temperature as a random walk around the average that we enjoy.)

Until someone actually launches a prototype, this is not happening. The economy of just doing everything on the ground is underestimated. And the technology simply is still not ready. LEO sats randomly falling down is a daily occurrence. I would love to see the Excel spreadsheet these investors are drooling over. It probably has less than 6 tabs.

Back when I worked at AWS, I wrote a one page “press release” about this concept where the value add was the weight/power reduction of customer sats that could offload on board processing to the “Cloud above the Clouds”. There is a bottleneck with the down/uplink ground stations to do the on the ground processing.

The biggest problem folks had was even with equipment with 99.9% reliability something breaks every day due the huge raw number of devices involved. And most network equipment is not any where close to being radiation hardened.

I had some fun with it with Bezo’s fist bumping folks because SpaceX was cleaning BlueOrigin clock.

I talked to one of their lawyers and didn’t hear anything afterwards. I left AWS and a couple of years later Amazon announced AWS ground station. I wonder how much my paper contributed to green lighting that project.

A month and a half ago: https://news.ycombinator.com/item?id=46286645

My dark theory is that the goal is to run an AI overlord in space such that it is difficult to counter it from Earth.

If you assume that these people aren't completely stupid, then there is some reason why they want this workload running at great physical distance from all the people down on Earth. It's probably not to protect people on Earth. After all they'll happily deorbit satellites and other junk from orbit and let it rain down on us. And they will happily destroy the environment with all those rocket launches too. Therefore it must be to protect the workload from us.

What is a workload that is something that people would probably want to destroy, and which would also provide enough value to offset the expense to launch and run in space? The only thing that might make sense is a military AI platform. Think something that observes Earth, launches missiles, and controls terrestrial drone armies remotely, with relatively low latency.

It gets built and launched thanks to endless military budget, and once it is up there, running such an AI from space means that effectively the only people who can take it out are nation state level foes who can launch rockets into low earth orbit. And this thing is a satellite, probably part of a network that is watching the Earth all the time. Start building something that looks like a rocket launch site, and the AI will see, then you get hit by a missile or taken out by a drone first before you get a chance to attack the platform.

It sounds like sci-fi, but in the future, if we let it happen, there could absolutely be nearly invulnerable autonomous AI platforms in space overseeing everything, and making decisions, and issuing commands. Of course there could still be a massive solar flare event, or a Kessler syndrome event that releases us all from AI enforced servitude. Anyway, it's a not so fun thought experiment, and let's hope this stays sci-fi, so we can just enjoy a fun Hollywood film about this rather than experiencing it firsthand.

Closest thing to a usecase I can think of are all military in nature. There's an argument that AI in space only begins to make any sense if the data source you are processing is also originating in space, and you need (for reasons) to run models on it in space before downlinking the results.

Maybe there's a very latency sensitive need to send realtime targeting information to a tomahawk missile in flight? But it's also too bandwidth, compute or cost intensive to send a firehose of raw spy-satellite data to a disposable one-way attack munition?

The data centers in space are actually for the spy satellites to use. That's all I got for practical applications.

Starship payload: 100,000 kg (100 tons). Looks like they talked about 150 tons and even 250 tons. My understanding is that they can be adding more engines to get more thrust.

https://www.nextbigfuture.com/2022/02/spacex-reusable-rocket... -- looks like target price for Starship launch would be $3--$5m according to the author.

Wouldn't the /kg price to SpaceX be:

3000000/100000 = $30/kg -- 5000000/100000 = $50/kg?

If they recover everything and produce fuel at scale, wouldn't it drop the cost even more.

What many people quote here are commercial rates, I think. SpaceX won't pay those prices.

Can someone check my math

Elon has used the greater fool theory for so long that they no longer exist on earth (at least fools with money who aren't also using the greater fool theory). It makes perfect sense he would focus on space because if he does find aliens it'll be an entirely new investor pool for him, and he desperately needs that now.

The bull case IMO is that you can just produce very standardized ai satellites, load them into Starship, blast them off and have them work. And that the cost of that versus permitting etc will be less than trying to do it on land. I kind of believe it could get there. We could build nuclear reactors next to giant facilities but...we can't really seem to do it in the US? China seems to be able to do it.

PS. I think the authors argument that millions of satellites might run into each other is silly. There are like 1.5 B cars.

I was listening to a podcast featuring Gavin Baker and he went on and on about models being defined in generations, and we will be moving from Blackwell generation to Rubin generation soon and it will be awesome. This is not something I know a lot about and he sounds like an expert I could learn so much from.

Then he talked about datacenters in space and this is something I have some appreciation for, and I immediately knew he couldnt have done much Physics, and sure enough, I was right.

There are "experts" out there who basically have no idea what they are talking about, "it is absolute zero in space in the shadow!", as though radiative cooling is that effective.

And that's not even talking about part failures. How do we replace failed parts in space? This is a scam, but everybody is afraid to openly challenge eloquent "experts" who are confidently wrong.

I always thought that in the case of a rouge AI breakout that we could just cut the power or network. This makes both impossible. The sick genius of SkyNet was having the most defensible infrastructure when it became clear that whoever controls the biggest robot army can take out enemy data centers and control the world. Now I hope that shooting down LEO satellites is cheap and DIY-able.

I think it’s all farce and technically unsound, but I also think that grok-5-elononly is a helluva drug. It’s really got him ready to rally investors behind “spreading the light of consciousness to the universe”. Oh to see the chat logs of their (Elon and his machine girlfriend)’s machinations.

I think the thing I often see missed in these discussions is the cost and time burden imposed by regulation. It's nearly impossible to build power plants in the US today. Launching satellites while hard, solves this problem.

Even if it's more expensive, Spacex will be able to deploy hardware when no one else can because all the gas turbines and existing power plants have been exhausted and the lead time to build new ones is 5+ years out because of the bureaucratic overhead.

> Data centers in space only make sense if they are cost effective relative to normal data centers.

Author made a fatal mistake. By flying enough hardware in space, you can simply blot out the sun and steal their solar capacity. Drink their milkshake with a long straw!

Data Centers in space make no sense due to radiation.

You cannot do two things at the same time:

1. Make electronics small. 2. Make electronics radiation resistant.

It’s a numbers game. The denser things are packed, the higher the probability that a random high energy particle or ray will damage something.

20 years ago NASA was buying old chips, because those were less susceptible, modern “radiation hardened by design” chips are better than those, but still slower than those for planetary use.

I loved when we would have an HPC server crash and we would analyze the issue and the vendor would respond, "probably a neutrino strike". I can't imagine this being more complex, given all the constraints of being in an orbit. The hardware depreciation, and the need to eliminate charge buildup and excess heat. Placing servers in the Arctic seems a better solution, at least the cooling issue is resolved.

This whole thing is Musk just trying to keep the hype train going. Musk has learned one neat trick from all of his (quite admirable) success with Tesla and SpaceX: hype is more profitable than actually doing stuff that generates value now.

Tesla's valuation has been nuts for a while. The music was going to stop playing at some point, so something something robotaxis, something something androids, something something AI. Keep the investors duped while you can move money around and leverage it to stay relevant.

Cars are out, social media as well (especially X), but Space is still in, and even more so AI. So let's move the cost center with world domination potential (AI) over to the one company that's making money and has a still has a cash-out potential via an IPO.

I'm just so tired of it all. I actually think 'boutique' businesses (companies that generate real value to real users and are profitable now) are the only thing that can save our economy medium-term, but investors and the government are having none of it. And the result is that these bait-and-switch scams will continue.

One major point I haven’t seen mentioned is maintenance.

Nvidia GPUs, particularly H100s, have a failure rate orders of magnitudes higher than traditional CPU-only hardware. I myself have accidentally melted an H100 during a large-scale training run.

While it’s trivial to replace a broken GPU in the ground, it seems to be infeasible in space during the life of the satellite. Getting a human or robot “fixer” spacecraft to it would likely cost more than the $30K GPU itself.

I wonder if the author was making similar arguments against solar power 20 years ago. The case for both isn't one of immediate ecenomic advantage, though that may come with sufficient development like solar has had. If you take it as a given that compute demand continues scaling, at some point we will need to shift power generation off Earth, and it's a lot easier to move computed data streams instead of terrawatts of power.

Yet I do think there's a narrow use case where space compute might make sense (for instance, niche workloads colocated with space sensors), but that's very different from "frontier AI training"

Just like an idea of using an oil-powered carriage instead of a good'ol horsie was in 1910.

Listen, I totally agree, the tech makes absolutely no sense. It does not. But the fact that someone is willing to spend money on figuring this out is pretty good. The worst thing is going to happen, we'll have a cheaper space travel. And let the guys to have the first hit at it, wasting money on an enormous amount of research needed.

Ain't my money being spent.

As long as we don't have to use Russian rockets to send the US payload to the orbit, I'm cool with it.

It’s less about putting compute in space as occupying that space before anyone else does. For any reason: spying, space warfare, network and communication.

First mover advantage, and all.

> Ground-based solar panels have been getting more cost effective for decades and show no sign of slowing down.

I'm no expert on solar but I thought there was some upper limit on how much power ground-based solar panels can generate per area based on how much energy gets through the atmosphere all the way to ground - and that panel efficiency was approaching that limit.

However, I don't doubt ground-based panels can continue to improve in cost and other metrics and thus exert competitive pressure on space-based solutions.

It doesn't make any sense to me either, but there are lots of things like that where the other thing is harder. As an example, a thing people say online a lot is something like "Why do the techbros build self-driving cars instead of just putting it on rails for efficiency and then they could call it a TRAIN?"

The answer to that is that coordination problems are really hard. Much harder even than what are currently unsolved engineering problems. In fact, SpaceX can only launch from California because they have DOD coverage for their launches. Otherwise the California Coastal Commission et al. would have blocked them entirely. Perhaps the innovation for affordable space Internet is combining it with mixed-use technology.

The truth is that in America today self-driving cars (regulated by a state board run by bureaucrats) are easier to build than trains (regulated by every property owner on the train route). Mark Zuckerberg tried to spend some money evaluating a train across the Bay and had to give up. But Robotaxi service is live in San Francisco.

So if there is an angle that makes sense to me it's that they anticipate engineering challenges beatable in a way where regulatory challenges are not.

Computing hardware that isn't rad-hard is going to have a bad time without a handy atmosphere for shielding.

And hardware that is happy in high-radiation environments is not going to be fast.

It makes a misleading argument about the price of solar panels falling. The cost of solar power installations has been flat for a decade because it's dominated by other costs.

Also why talk about training not inference? That needs data centers too and could be what they're intending to do.

So this post is clearly not an effort to objectively work out the feasibility but just a biased list of excuses to support the author's unsubstantiated opinion.

> Kessler syndrome: a cascading explosion of debris crippling our access to space

I'm taking the parts of this write-up I don't have expertise with a grain of salt after seeig this.

Kessler cascades are real. Particularly at high altitudes. They're less of a problem in LEO. And in no case can they "[cripple] our access to space." (At current technology levels. To cripple access to space you need to vaporise material fractions of the Earth's crust into orbit.)

Current analysis shows space-based compute costs roughly 3x more per watt than terrestrial equivalents, requiring launch costs to fall below $200/kg before achieving economic parity—a threshold unlikely before the mid-2030s even with Starship’s full reusability.

While technically not impossible, the space data center vision appears primarily designed to support SpaceX’s anticipated mid-2026 IPO and justify a $1.5 trillion valuation rather than solve near-term compute constraints.

What data centers in space enable is protection for the compute of near-superintelligent AIs from the interference of humans.

As an alleged human, I'd like to preserve my option to interfere.

ViT (Vision Transformer) fine-tuned on a Starcloud satellite in space (using the Flower framework) -- to the best of our knowledge, this is a world first: https://flower.ai/blog/2026-02-02-flower-labs-and-starcloud-...

Assuming that we place an iron ball (ideal sphere-shaped and thermal conductivity) on the SSO (solar synchronous orbit), how hot can the object be?

Given the solar constant 1361 W/m^2, you can calculate the temperature range based on the emissivity and absorptivity. With the right shape and “color”, the equilibrium temperature can be cooler than most people thought.

I suppose that a space data center powered 100% by solar is no different than this iron ball in principle.

"Data centers in space only make sense if they are cost effective"

The author forgot to add that this is only true from the perspective of their own bias.

To someone else it might make a lot of sense, e.g. someone who expects militant resistance to the "data centers" from the general public or some other actor that is highly unlikely to achieve space capabilities.

The article kind of ended all of a sudden without much of a conclusion… but as most people by now have realised once they heard of the merging of Musk and Musk, it sounds more likely just a way of shifting money to pay himself rather than to actually build anything he says.

I’d even bet that when they do IPO, there will be ZERO mention of “space data centres” in the prospectus!

AST Spacemobile is successfully deploying cell towers in space; to compete with Elons Starlink. Not to mention ASTS is collaborating with American Tower, Google, ATT, Verizon, Nokia, and other big dogs for this venture. Now a DC is magnitudes different then a cell tower/satellite but hey .. if the RoI is there, it can be done

Consider: If you genuinely believe that the only important goal is to make life multiplanetary, (and note I'm not defending this position here, just asserting it as an explanation of behavior)

then anything that drives money towards your work on that goal is worth pursuing particularly if you think time is short.

Clearly the desire to have data centers in space is so that AI can control humans remotely without having to worry about backlash and potential dismantling.

Besides this, it's concerning how much stuff we're sending to space. One day we'll have to start worrying about satellite parts falling on us.

Heat energy shedding is often talked about as an Achilles Heal of orbital computation.

But heat radiation rates are proportional to temperature to the 4th power!!!!

That is a magical law. The quality of heat pumps used to concentrate heat, will drive the economics and structure of heat dissipation.

Seldom do we get constraints that favorable to work with.

I'm not sure datacenters in space have to make suense to everyone, or from the perspective of earth.

Taking a creative step back, perhaps datacenters in space support something with Mars?

As much as that might not seem realistic, I also have to counterbalance it with operationalizing and commercializing SpaceX, Starlink and Tesla relatively quickly when so much stays at the R&D stage for so long.

I have my personal reasons to hate Elon. But the article is full of fluff and lacks imagination, typical of the "the world is static and will never change" mindset.

What they are trying to do is an a very ambitious engineering challenge in several highly integrated domains, from spaceships to robotics, gpu, server design , ai. Typical stakes are high margins are high.

Project also pushes boundaries of what human can do the same way starlink did. 20 years ago starlink scale was also an "impossible" thing. Is it possible now to push one gpu and serve it from space? Yes, can you do it at scale? Big question.

Obstacles :

Price per kg to orbit. They aim to go from $150 to $10 per kg. Can they deliver? Big question, but having something that demands so many starship, like GPU heavy tasks, will help them achieve this goal. Benefits? No rent, no cooling issues, cheap sun-powered electricity 24 hours a day, unlike anywhere else on Earth.

Jurisdiction. Servers can't be shut down or taken away by police, etc.

Cooling. Yes, it's a vacuum, but with $10 per kg, you can deliver pipes and coolant, and since you don't have space constraints, you can build these pipes with a robot, making that datacenter extremely cheap.

3. Labor. If a robot can do primitive tasks combined with design that is fully remote, you labor costs goes almost to 0.

the output: with $10 per pg, delivering solar panels, coolant + robot for some urgent fixes. Robots even with current technology can swap a harddrive for example, especially if hardware is built to be mantained by robots not human. You don't need large construction, you invest into design, that once assembled , cost you maybe comparable amount of hardware to deliver. After that it runs for free!

The economy if this obviously beating anything exised on earth.

I was gonna say it is good for low-ping game servers, but then I remembered that the data center would literally be orbiting around the planet and ping would fluctuate by tens of milliseconds every few minutes.

I had this idea in the beginning of last year and since I wanted to somehow get into space infra started doing some calculations - the area of arrays required kinda made me scrap the whole thing. But kinda curious since this is back as a mainstream topic.

The worst thing about this isn't that it makes no sense. It's that it doesn't even _try_ to make sense.

These companies wanted to merge for financial reasons and the invented reason is nonsensical. We shouldn't even give the nonsensical reason the benefit of trying to make sense of it.

Isn't Starlink already basically a distributed datacenter in space? they have like ~9k+ satellites up there already at least according to: https://planet4589.org/space/con/star/stats.html.

what am I missing here?

I'm glad I read HN.

My take-away is - SpaceX is still an extremely good stock to hold. However, the stupid money will buy the stock at IPO on the promise of space datacentres.

When SpaceX inevitably u-turns on this plan and the stock plummets temporarily, THAT will be a good time to buy in.

It's fun to debate this and all, but the reality is that datacenters in space are going to happen, and soon - maybe even this year. If we've come this far, then there's already a viable plan that we just don't know about yet.

How much of this is because putting data centers in space is WAY harder for any terrestrial government to get their hands on and seize or block?

They make no sense otherwise.

The only other thing I can think of is the whole thing is just a scheme to get investment and they’re never going to actually go through with it.

At this point I kind of think the former is more likely.

I guess the xAI/SpaceX thing is mainly a financial move and they made up an interesting story to give it some context

I'd be curious to know simply how large the thermal radiator necessary to keep a typical GPU server cooled would be. Do they completely dwarf the server size? Can you do something with some esoteric material that is not particularly load-bearing but holds up well in space to get around some of these challenges?

Electric cars make no sense.

Reusable rockets make no sense.

Autonomous cars make no sense.

Data centers in space make no sense. <--- You are here.

Humanoid robots make no sense.

Data centers in space make sense because its nigh impossible to build things terrestrially. NIMBYism is so out of control the largest solar array in the US in the middle of the mojave got cancelled because it would interfere with the view.

"Just change the law" ok sure we'll get right on it.

Thinking of power infra. Even solar. Doesn't that last 20 or 30 years at least? With some maintenance, but before full overhaul. So in space you would probably decommission it at same time right? Wouldn't that be additional cost?

He's going to do a DOGE (memecoin not government agency) equivalent over phones new satellite links to his SpaceX sats outside anyone national jurisdiction. Worth the possibility of taking over being the world's global currency unconnected from any/all government.

With all that great tech to land and reuse rockets, they still need to be propelled into space using... kerosene. That's right. 1 million satellites launched into orbit using kerosene.

Does not feel like a vibe.

I bet they can already weaponize their satellites to prevent the launch of other satellites.

Putting data centers in space keeps them out of reach of humans with crowbars and hammers, which may have been a vulnerability for those robots Tesla is building.

No, but protecting x/xAI from bankruptcy by linking it to the most promising company in Musk's portfolio does. You just need a justification.

This is while they try to find a solution to earn money with it.

What is this website?

The website insists that you let it record your voice in order to show you the dangers of AI. Is it trolling the visitor? https://civai.org/talk

Feels like this is about as unserious as flamethrowers, the Boring Company, and Hyperloop.

We're living in the Age of Distraction… amusing ourselves to death (as usual).

If someone had the tech to cool stuff in space, that is required for this to happen, they’d have tons of easier and more lucrative opportunities right now on Earth to become the new richest person.

Where is the tech?

Space - no. Moon - yes

Space is cold but has little mass. Either heat can radiated or transfered. To transfer heat, mass which easily absorbs heat is required. The moon might be suitable for that.

Google, Spacex, several startups are all doing this. The best people in their fields think it might be viable. I'm skeptical as well, but you do wonder if maybe they are right and how exciting that would be.

Surprised nobody here linked https://andrewmccalip.com/space-datacenters.

Cool! If there are people working on something, despite others saying "it makes no sense" I assume it's a hard and interesting enough problem.

Data centers in space make sense when you want it to cost 200x more than on land, be unavailable for repairs and upgrades, and be either high latency or be out of commission during periods of darkness.

Reasonably sure this has less to do with putting data centres in space and more to do with getting them less auditable (see the other news about X getting raided about Grok)

> Data centers in space only make sense if they are cost effective relative to normal data centers.

This statement is actually completely false. The bottleneck is not cost of building data centers, but the energy accessible on the planet. How much we're willing to pay for increasing that is currently very unclear, but it's far more than the current cost of building a terrestrial data center.

As Jensen Huang famously touted their performance per watt, saying "Our customers won't buy our competitor's chips even if they were free."

Can't wait for competitors destroying the other guys installation because just like international waters, there is no police or border there.

Of course it makes sense.

The regulatory framework is getting more and more difficult for data centers.

The options are move to countries with less of an uphill regulatory burden (UAE?), but this comes with other issues.

Space it is.

I don't get the point at all of these. You:

- have very non-deterministic latency

- are located outside of a country that can protect you (ie China could disrupt your space data center)

- have to pay millions of dollars to swap out hardware

Is there any insight into how Starlink solved cooling? One 'expert' insisted that there is no reason to expect that data center satellites would generate any more heat than starlinks.

It's not supposed to make sense. It's supposed to be cool and signal that demand for the stock will not go down.

Given xAI's gross disregard for environmental regulations in building Colossus, the reason for building datacenters in space seems obvious: there's no EPA in space.

The bigger issue: datacenters in space are disposable. All the extremely recyclable aluminum, silica - you extract it, manufacture it and instead of recycling it when it’s done you incinerate it in the atmosphere and scatter the ashes far and wide across the earth, the harder to recapture later.

You do this when the most fragile part in the system fails. Solar panels good for 25 years but the SSDs burn out after 2? Incinerate the lot!

This kind of thinking is late capitalist brain rot. This kind of waste should be a crime.

Elon announced this so he could troll the comments on HN and get all of this incredibly valuable armchair expertise in solving his problems.

I feel like he has no intention of implementing this. It's all just justification for it to not hit up against an regulatory objections to combining the companies.

It makes sense if you want to avoid tax. You can put artificial costs and deduct them. Nobody is going to go to space and check.

It's not supposed to make sense when you're screening for supporters who will believe anything you say.

Remember what the Luddites actually did? They sabotaged the machines that were disrupting their livelihoods. If AI is as disruptive to large numbers of workers as some people think it will be, keep in mind it's a lot easier to destroy a GPU that's stored on earth than one in space.

Anyone planning expenditures as large as a modern data center thinks about all kinds of risks (earthquakes, climate, power, etc), and so perhaps there is a premium for GPUs that are out of the reach of your median angry unemployed guy.

(yes, this is nuts, but I can easily imagine some fever-dream pitch meeting where Musk is talking about it)

That's the point. Nonsensical ideas (like humans on mars) drive valuations higher. There is not even a point to argue about practical matters.

I agree with the author and the bit about xAI and investors makes sense. But why does a company like Google invest in this ridiculous idea?

How do you protect a datacenter in space from evil nation states that have an appetite for your GPU cards?

Ground-based data centers will always be cheaper. There is no advantage in space that makes it worth spending more.

heat dissipation is one thing - another is the recycling - anything he shoots into the orbit will essentially be disposable, single use DCs. Once they fail, it will be just a dangerous junk waiting to be deorbited. And all the precious materials which normally get recycled will be lost....

After the hyperloop fiasco I don't understand why anyone gives Musk any credibility at all

you know you're looking at some hard analysis when they use the number "gazillion". can I get that one in scientific notation?

This only makes sense if it somehow helps to evade some kind of regulation. I'm not quite sure which though.

A more reasonable project would be repurposing portions of the ISS for a data center and using that as a POC for larger scale stations.

I don’t know, it probably would have been useful if Cyberdyne Systems had developed its AI in space?

where do you put things, so that no one will be able to warrant thier way into access?

entirely out of jurisdiction, where it is prohibitively expensive to travel, and impractical for any physical seizure.

you dont need to compute, just store it and P2P amongst satellites.

essentially an orbital NAS.

You might want some compute in space that you know is very hard to physically interfere with.

But general purpose compute no

> Training and serving frontier AI at scale takes hundreds of thousands of GPUs. xAI’s Colossus cluster reportedly has 200,000 GPUs. OpenAI has plans for millions of them. Competing in this market would require launching hundreds of thousands, if not millions, of satellites into space

No? You'd only need one with lots of gpus on the ship at the same time

What is the real-world advantage of putting datacenters in space?

Data centers in space make perfect sense, in exactly the same way as a jetpack made perfect sense. It is an excellent vehicle to ride out some juicy government contracts for as long as you can keep the grift going.

https://pluralistic.net/2024/05/17/fake-it-until-you-dont-ma...

What jurisdiction does a data center in space fall under, anyway? The one of the nation that launched it?

I just purchased a sandwich I made from myself in a deal that values me a $1tn. I plan to make toasties in space.

This blog post has some sliders you can tweak to see if you can make the numbers make sense: https://andrewmccalip.com/space-datacenters

"So here's what I did. I built a simple model that reduces the debate to one parameter: cost per watt of usable power for compute. The infographic below lets you change the assumptions directly. If you disagree with the inputs, great. Move the sliders. But at least we'll be arguing over numbers that map to reality.

The model is deliberately boring. No secret sauce. Just publicly available numbers and first-principles physics: solar flux, cell efficiency, radiator performance, launch cost, hardware mass, and a terrestrial benchmark that represents the real alternative: a tilt-wall datacenter sitting on top of cheap power. "

"Here's the headline result: it's not obviously stupid, and it's not a sure thing. It's actually more reasonable than my intuition thought! If you run the numbers honestly, the physics doesn't immediately kill it, but the economics are savage. It only gets within striking distance under aggressive assumptions, and the list of organizations positioned to even try that is basically one."

What if they diverted a decent sized asteroid into earth orbit and put the data center onto that? Could it be put into a sun-synchronous orbit, cover one side with solar cells, and use the backside of the asteroid itself for cooling?

What if you just took some ketamine and tried again? Does it make sense?

Whatever it is it’s not driven by sense or even feasibility of data centers in space.

To me it looks like the next Musk’s grift. Remember Mars? Have you heard about it recently? He threw it to the Internet and everyone got excited for a minute. Then nerds did quick math and it didn’t make any sense. And so everyone forgot about Mars. This is the same. Hype everyone up for a week or two to inflate stock before the merger/purchase/IPO/whatever. That is all.

This is when you know we reached peak AI. Data centers in space talk.

This makes the same amount of sense as colonising Mars.

I thought chips need to be radiation-hardened to work in space.

I’m surprised everyone is worried about heat dissipation.

Datacenters in space is ambiguous enough to mean on lunar soil which provides plenty of heat dissipation using geothermal heat pumps.

Similarly mass to orbit is also less problematic if silicon factories (including the refineries) are built on lunar soil as well.

Two reasons why it makes sense (really really good reasons):

1) Water scarcity and energy scarcity here on earth

2) It will drive down launch costs and promotes investment in orbital facilities and launch capabilities.

those two reasons alone are enough.

Data centers on earth don't make sense either.

Data centers in space have one advantage: FBIs can't physically raid them.

Keep talking like that and people will colonize space

Three counterpoints:

1) Kessler syndrome is a contingency.

2) This is a logistics issue, not a physical impossibility.

3) Those are different tradeoffs (solar in space). There is not really an argument there.

All in all this is extremely weak reasoning, which is quite the contrast with the definitive title.

I throw this to the "nerds need to feel smarter than Elon" pile of articles. :)

Let's do some napkin math on it

Current satellites get around 150W/kg from solar panels. Cost of launching 1kg to space is ~$2000, so we're at $13.3(3)/Watt, that just power, let's assume that cooling will cost us same per kg, the same amount need to be dissipated so let's round it to $27

One NVidia GB200 rack is ~120kW. To just power it, you need to send $3 240 000 worth of payload into space. Then you need to send additional $3 106 000 (rack of them is 1553kg) worth of servers. Plus some extra for piping. We're already at $6.3 mil a pop for just hauling it up to orbit, with no cost of solar cells included

I'd imagine comparable hardware for just some solar + batteries on ground is around $200k. I dunno where the repeated 5x cost number comes from. I suspect whoever pushed it was just lying

But it's absolutely amazing hype and memevestors love it.

it probably wouldn’t be a bad idea to have some backups in space. It could imagine this being a premium AWS offering. A storage class for S3. Put one on the moon too. True cold storage ha!

It sounds cool and gets investors.

I mean everything he does is so honest, rational and well thought out in detail, right?

How's that full-self driving promised for decades working out?

How's the destruction of USAID working out (oh you wouldn't know a million dead now)

We already have a data-center in space, sort-of, here's how many radiation panels it has to deploy for just the heat produced from the small number of low-power computers

* https://i.sstatic.net/cpIBo.jpg

(ISS, all those white panels are thermal heat radiators)

It seems quite telling we are even discussing this.

No no, let Musk cook. This definitely won't be SpaceX's Cybertruck moment, where they completely throw away their first-mover advantage by wasting five years chasing after the egotistical boondoggle of a delusional megalomaniac.

A thought experiment. Imagine that you had some magic way of getting all the electricity you wanted at the south pole, you had good internet connectivity, and the various treaties about the place weren't an issue for you. Would you want to build a data center there?

Seems like a pretty obvious "no" to me. Loudoun County is a much better choice, just to pick one alternative. Antarctica is an awfully inhospitable place and running a data center there would be a nightmare.

And yet it's way better than space. It's much easier to get to. Cooling is about a thousand times easier. The radiation environment is much more forgiving.

This whole concept is baffling to me.

(Incidentally, a similar thought experiment is useful when talking about colonizing Mars. Think about colonizing the south pole. Mars is a harsher environment in just about every way, so take the difficulties of colonizing the south pole and multiply them.)

Like there isn’t enough stuff floating up there already.

If we won't stop what he is doing with grok and ai-generated CSAM, he will be completely free from oversight up there.

"Let him cook" makes so much sense here.

Eager Space [Orbital Data Centers Yes or No](https://www.youtube.com/watch?v=JAcR7kqOb3o) Goes into great detail with extensive calculations (for a YT video at least). TLDR: Cost to orbit needs to be under $200/kg before it makes sense.

I mean, we just need to reach L2 Lagrange point. It is definitely easier than going for Mars. Right?

I am willing to bet the whole xAI/SpaceX merger is simply a ploy by Musk to evade releasing accurate historical information about SpaceX's finances. How much did it actually cost SpaceX to launch a kilogram of payload into space each year? How much is NASA actually donating them, per each year?

I mean, I still remember promises of $1000-per-kg for space launches, and how e.g. Gigafactory will produce half of the world battery supply, and other non-scientific fiction peddled by Musk. Remember when SpaceX suggested in 2019 that the US Army could use its Starship rockets to transport troops and supplies across the planet in minutes? I do. By the way, have they finished testing Starship yet, is it ready?

Next up, the Boring Company gets imaginary contract for underground datacenters, is now valued at $500B.

But data centers in the sea...

Data centers on earth alone don't make sense if we want to expand further into the galaxy.

The top comment: "Musk is up to something here."

It never fails here. Ya'll are soooo determined to assume ulterior motivations. He has always been direct about his motivations, whether it's about politics or business decisions.

To suspect his whole plan for datacenters in space is a ruse or something to drive up some stock price (or whatever), is... just ridiculous. You really think they person who leads SpaceX (more satellites than the rest of the world combined) and Xai (with a competitive frontier model in 2 years starting from scratch), and Tesla (more inference compute than any company on Earth) really knows less than you about the math and physics of this idea??

His immediate focus for Starship has shifted from Mars colonisation to exponential expansion of intelligence, as he thinks it's the best path to extend consciousness. Ridiculous or not, he believes that, and that's the motivation.

Like I’ve always said love him or hate him Elon Musk is a SPACE OIL SALESMAN!

You can debate this until you are blue in the face. If the costs are less they will do it. If they aren’t they won’t do it. That’s the only sense that needs to be made.

"So if this is clearly nonsense, why are serious companies and investors piling into it?"

What does "serious" mean

AI in space makes no sense because the data center will be distributed and half of the time your processors will be waiting for data (if you are lucky). When they are working, you need to cool them down. When they finally heed the call of gravity, your vibe coders can see the vapor of their work in the sky and you throw the entire unit as a loss (might be a net positive for tax purposes).

This is BS, everyone knows that this is BS, but because this is Elon, there are still people who don't call out the BS.

It might be distraction, he might be delusional, he might be asking his investors to stop asking for profit by giving them shares from SpaceX, but this is not him discovering new physics.

Another thing that doesn't make sense about them is that DCs get a lot of out of physical locality. Caches become hot as different use case spin up and down during the day near their customers.

If the nodes are spinning around the earth at orbital velocities, then all the benefits of physical locality are thrown out the window.

Counterpoint: https://x.com/CJHandmer/status/1997906033168330816

(If you can't xcancel it yourself your hacker card is revoked.)

Of course it makes sense. It's a cool story to pump up the valuation in the AI datacenter boom. This meme will keep on delivering until (if) the AI bubble bursts.

We were supposed to be on Mars right now, but I guess data centers in space are nice too. Kinda disappointed they aren't on the moon.

The whole premise misses the point, that earth is somehow in the very same space too.

Adding a global UHVDC grid to even out dips in local PV performance due to cloud cover and the diurnal cycle on spaceship earth seems to be magnitudes cheaper and scaleable than this loony pitch.

The only thing making this hard is requiring supranational collaboration.

Don't let common sense stop you from a good time.

It's lala land nonsense.

- Data centres need a lot of power = giant vast solar panels

- Data centres need a lot of cooling. That's some almighty heatsinks you're going need

- They will need to be radiation-hardened to avoid memory corruption = even more mass

- The hardware will be redundant in like 2 years tops and will need replacing to stay competitive

- Data centres are about 100x bigger (not including solar panels and heat sinks) than the biggest thing we've ever put in space

Tesla is losing market share (and rank increasingly poorly against alternatives), his robots are gonna fail, this datacentre ambition needs to break the laws of physics, grok/twitter is a fake news pedo-loving cesspit that's gonna be regulated into oblivion. Its only down from here on out.

prompt: what's the term for financial moves where you keep finding new investors to pay off the previous ones

GPT-4o mini: The term for financial moves where new investors are continually recruited to pay off previous ones is often referred to as a "Ponzi scheme." Another similar term is "pyramid scheme," where returns are paid to earlier investors from the contributions of newer investors, but with a structure that typically requires participants to recruit others to earn returns. Both schemes are unsustainable and illegal.

The French government issued a child porn warrant for the CEO and it isn't even a topic for discussion. That's what doesn't make sense to me. It's silly to talk about solar panel prices like reality matters at all to his cult of followers. It doesn't have to make sense. The less sense the better.

Data centers in space are the logical progression from the multi trillion business of m2m and edge computing. It removes all physical limits to investment.

I'd like to see data centers in the ocean, before space. Water there is near 0c and doesn't boil til 400c-500c.

When an invention has not been made before it’s usually because people are lacking an insight that the inventors have.

You can’t read a 300 word article in 1930 and know that a formula 1 engine could not be built.

A pie in the sky

hello,

as always: imho. (!)

we already had this topic before, an example for another good article regarding physical arguments against this idea would be:

"Datacenters in space are a terrible, horrible, no good idea" ~ late 2025

* https://taranis.ie/datacenters-in-space-are-a-terrible-horri...

TL;DR: It's not going to work.

idk ... maybe elon has something else in mind with this merger!?

cheers,

a..z

How else would you secure skynet against Sarah Connor?

What? A pump and dump scheme? I am shocked I tell you, shocked

*Data centers in space only make sense if they are cost effective relative to normal data centers*.

Disagree there are bunch of scenarios where Data Centers in space make sense. Like nuclear annihilation and having vaults across the globe to communicate and get back lost information because ground data centers would be wiped out by EMP from blasts.

Facts.

Just do the basic thermal heat transfer math.

I can assure this author: strapping a company that lights money on fire (today, maybe not tomorrow) to a cash flow enterprise makes the IPO harder, not easier, in the absence of credible plan. The market speculates, but it’s not being completely irrational. I’d actually be surprised if we didn’t have factories or data centers in space one day.

This sound like a Musk "idea". click. Of course.

After looking for a top level comment pointing to why instead of how, I logged in just for this as I could not find one. Extremely bullish on this move, let me try to explain.

As most engineers realize right away, it is not going to be profitable to operate a regular datacenter in space, per the article (and I agree), so something else is going on here. Almost all the discussion is about feasibility, which is not by itself going to explain the situation.

It is clearly somewhat feasible to build Starlink level infrastructure and operate it profitably. I would posit that the narrative is a funding vehicle for a more conservative, incremental objective.

The very fact that the infrastructure is in space places the datacenter on the legal and geopolitical high ground. It's hard to raid servers if they are in orbit. It's hard to disable, audit, or arm-wrestle into submission. It doesn't have to have the scale we've come to expect in 2026 to be useful. And it's for inference, not training, of course. Useful levels of inference is computationally cheap. There are implications with the financial system as well.

In combination with PLTR technology, what I see is another intelligent and strategic move by Musk to enable and be part of hegemony. He is a central player not making decisions in isolation. They are playing a game with different rules, and therefore different unit economics.

how much latency would a minecraft server in space have?

You’re missing one important point: radiated power scales with the fourth power of temperature. Could it be that xAI has a chip capable of operating at very high temperatures?

Honestly, it is funny that people even seriously discuss this. I mean, now. It is such a blatant bullshit that you'd expect this time people would say "okay, now Musk went too far, nobody would buy into this". Yeah, I wish.

Comments full of EDS. Everyone is a rocket scientist in here also.

Truth doesn't matter.

What matters is that investors and shareholders love to hear about future space data centers.

Obligatory /s.

no, no, no, the key enabler to space datacenter is complete out-of-world computer 3D printers. You print entire 130nm, hell, even 130 micrometer GPUs and DDR2 VRAMs to go with, entirely on the Moon solely from Moon dusts, and shoot the complete satellites out into Earth LEO using maglev sleds. PUEs, opex, nothing matter because the Moon factory is self contained and don't interact with Earthian economy at all. The ssh key into the factory will be the source to free money to whoever holding it.

Is that possible in our lifetime? I'd be optimistic about that. Can SpaceX pull that off? Space what? ...

Space offers some unique benefits that enable computing that’s impossible or very hard to do on earth. E.g. Super conducting computing is possible, which can be thousands times to millions times faster than current CPU while using very little energy. When the satellite moves in the shade of the earth, temperature drops significantly. It can be low enough to enable superconducting. When the satellite moves under the sun, the solar panel can start charging up the battery to power the ongoing operation.

What’s there not to like? Superconductors. Free electricity. No cooling necessary.

Put those three together and maybe it’s possible to push physics to its limits. Faster networking, maybe 4x-5x capacity per unit compared to earth. Servicing is a pain, might be cheaper to just replace the hardware when a node goes bad.

But it mainly makes sense to those who have the capability and can do it cheaply (compared to the rest). There’s only one company that I can think of and that is SpaceX. They are closing in on (or passed) 8,000 satellites. Vertical integration means their cost-base will always be less than any competitor.