jacobgold
19 hours ago
I completely understood the idea of Starlink and expected that it would be successful and useful, which it is. I've worked in data centers for decades now, and I am incredibly skeptical of the "data centers in space" sales pitch. It seems like an actual scam.
Data centers submerged in the ocean or placed in the desert seem much more promising. But I have only an enthusiast's understanding of rockets and physics, so I'm genuinely open-minded to the possibility.
Is there anyone credible who thinks this is a plausible pathway for SpaceX to make huge amounts of profit?
chris_money202
18 hours ago
Repairability and depreciation are the main problems. A earth data center can be repaired, depreciated, and recycled at EoL recovering some of the costs. SpaceX datacenters are a total write off from the moment they are launched.
vlovich123
18 hours ago
The Microsoft design of filling an airtight submersible structure with argon and dropping it to the bottom of the ocean floor is the alternative design - you’re not looking to do repairs but amortize the low cost of failures across the value you extract.
The biggest issue with space is not repairability but heat - when you’re in a vacuum the only way to disperse heat is through black body radiation and that’s horribly slow compared with normal mechanisms. It means you need giant physical structures whose sole job is to accept heat from the processing core and radiate it away and have so much more material that you can radiate it at the speed you generate. It’s a huge unsolved physics problem which is why everyone is skeptical.
nkrisc
17 hours ago
It’s not an unsolved physics problem. Every satellite in space has to deal with it and even the ISS deals with it by having massive radiator arrays that face perpendicular to the sun.
The problem with data centers in space is one of materials science and engineering: how to make radiators large enough and effective enough to cool it while also being economically feasible, both in terms of construction and getting them up there in the first place.
We can make a space data center right now. It would just be terrible and expensive.
vlovich123
9 hours ago
The maximum heat rejection capacity of the ISS is 126Kw.
Musk’s proposal is to put 1 rack per satellite drawing 150kw using 110 m^2 of radiators (1/4th that of the ISS). The only way to do that is by running the satellite at 71-100C which is a problem for the chips to actually run.
So the open questions are: * can they actually dump the heat and can they have the racks running so hot for so long * is it economical to in one year replace all the capacity you launched 5 years ago (you save up to 0.5B in electricity costs over that time frame but that doesn’t seem like a lot for having to replace that much capacity buildup)? And given they’re running racks way hotter than has been validated on earth, will those chips end up lasting 5 years (including space radiation).
Pretending like it’s a solved problem is neat but I’m not saying sure it’ll be so easy.
roryirvine
5 hours ago
Those temperatures aren't necessarily a problem for the chips (there are some minor design changes needed, so it's more a question of having enough volume to justify doing it). The real issue is that this is yet another thing you could do better on earth.
In other words, run fully lights-out datacentres that no humans will access during normal operation - this allows you create more extreme temperature gradients and to replace the atmosphere with CO2 (or even He2), both of which will make your cooling solution much more efficient as well as increasing rack density and perhaps even taking the place of a fire suppression system.
The reason that no-one's actually doing that at scale is that it's currently significantly more expensive than traditional datacentre designs. And yet, that's still much less expensive than boosting racks into space and then letting them burn up in the atmosphere five years later.
krcz
2 hours ago
Wouldn't it be possible to use heat pumps, making radiators 100C or hotter while running GPUs much below that?
Eddy_Viscosity2
2 hours ago
That's how space heat radiators already work. Which, by the way, add significant costs to both energy and weight for space-based data center. The problem is once you 'pump' the heat out is what happens next. With out conductive or convective heat transfer, all that is left is radiation of that heat. Which is the slow.
phs318u
3 hours ago
It’s as solved as FSD.
Eddy_Viscosity2
2 hours ago
> It’s not an unsolved physics problem. Every satellite in space has to deal with it and even the ISS deals with it by having massive radiator arrays that face perpendicular to the sun.
The problem is not solved for something of this scale, I think its solvable, but no has done anything at the size these would have to be. And if the physics and engineering can be made to work, they are unlikely to be solved AND ALSO be economical.
It's classic type problem where the choices are:
- economical
- in-space
- big
Now pick two.
There is also the unsolved problem that the radiators would be absolutely massive in area. Making damage from flying objects, meteorites, space jump, close to 100% likely over any reasonable life span. Repairs would be expensive AF. Again economics is the driver of why this is dumb.
croes
16 hours ago
Nobody said space data centers are impossible, it’s just wasteful and ineffective.
cucumber3732842
16 hours ago
Right, but nobody's sure just how wasteful. And at these scales small factors make or break things. That's why it's hard to predict who's bullshitting. A fairly small unforeseen factor here and there adds up to wild financial success or failure over the course of an entire project.
xienze
17 hours ago
I think it's not necessarily about being the cheapest option, but a more politically acceptable one. I don't think you're going to get people protesting a data center in space considering it won't be next to their house, won't use water, and won't lead to increased electricity rates. I could see companies paying a premium to keep the political heat associated with traditional data centers off their backs.
kibwen
17 hours ago
The physics problem regarding radiator arrays isn't unsolved, but it's not a problem that scales up gracefully. Small-scale radiators could get by via passive cooling, but large-scale radiators need active cooling, and now you need fluid, pipes, and pumps that all represent additional launch mass and points of failure (and the pumps are generating heat of their own, so now you need more radiators...).
aeternum
15 hours ago
Thermal dissipation scales quartically with T, that's about as graceful as you can get from a physics POV, very few things scale at that rate.
COTs GPUs throttle at about 90-100C but that's because they have plastic parts and solder that melts. Those are relatively easy to eliminate.
We haven't tried much to scale up operating temp.
rcxdude
14 hours ago
Apple tried the damnedest at that during their intel era. Silicon gets exponentially leakier at higher temperatures, and that will outpace quadratic growth easily.
(Electronics that works at 200C do exist, but they're not gonna meet a modern smartphone's specs, let alone a datacenter)
AnthonyMouse
16 hours ago
Doesn't active cooling provide counterbalancing options to improve efficiency though? For example, use multi-stage heat pumps with different refrigerants so that you can make the hot side very hot and thereby need less mass for radiators.
nkrisc
15 hours ago
So what’s the unsolved physics problem? Everything you’re describing are engineering challenges.
chris_money202
15 hours ago
Right, a heat exchange is reusable though on earth and can be recycled across multiple SKUs and thus depreciates longer. In space similar to how you can’t repair you also can’t swap.
bakies
17 hours ago
It's so, so cheap to buy tap water and dump it on the heat exchange.
munk-a
17 hours ago
With well considered engineering it doesn't even need to be tap water. If you have a closed loop thermal conductor that interacts with the components themselves you can then use really trashy contaminated water that just needs to be clean enough not to actively erode the heat transfer mechanism. We have setups like this all the time that use condensed air via cooling towers or salt water immersed heat sinks to discharge energy - it's more expensive than tap water but it isn't technically complex. So if it ever becomes unpalatable (likely due to politics) to use tap water there are some readily available alternatives.
The big win of being in space is just a worse alternative to using an intermediary heat transfer medium.
jacobgold
18 hours ago
That's actually not a concern I'd have, because hardware that has been sufficiently tested and burned in tends not to fail for a very long time.
I've done builds that ran for 5+ years with virtually no physical attention, just continual degradation as hardware is taken out of service. There's also not much money to recover from 5+ year-old hardware.
I used to run AI inference GPU servers in road vehicles, which is probably an even harsher environment than a single rocket launch, and the vibration problems are real but solvable.
nijave
17 hours ago
GPUs depreciate super fast. It might last 5-7 years but it's already outdated at 2-3
Also space has more radiation
asadotzler
17 hours ago
5 years is a Starlink's typical lifetime. Data center satellite lifetimes will probably be shorter. Demise sooner, replace more often. GPUs get more energy efficient every year and leaving the slower, hungrier chips up there much longer than 3 years seems wasteful given the cheap cost of launch.
I think this could be done at an interesting scale even on Falcon 9 alone. If Starship does even 20% of its early design goals, it'll beat Falcon 9 and we could see orbital servers being demised and replaced every 3 years, maybe even 2, for ones with abnormally high failure rates.
Now, whether or not this will all make money in the end has a lot to do with what's going on down here on terra firma and how long it takes to get useful capacity into orbit.
(It's taken 7 years to get Starlink capacity enough for serving 10M customers. Verizon FiOS did 10M in 5 years. AT&T Fiber took 4-5 years to deploy to 10M. So, space isn't a lot slower than terrestrial.)
maxerickson
12 hours ago
The efficiency of the chips only matters if the orbit is full.
If the orbit isn't full, all they are is additional compute.
croes
16 hours ago
Starlink rushed when they put the satellites in orbit, AT&T did the opposite. They did the bare minimum. So terrestrial was faster without really trying
kibwen
17 hours ago
> space isn't a lot slower than terrestrial
But it depreciates faster. That fiber run is lasting for 50 years, not 5. You need 10x the installation capacity just to keep up.
bakies
17 hours ago
uhh no I dont think the road vehicle is harsher than a rocket launch
jacobgold
13 hours ago
The rocket's payload most likely has higher peak vibration but only for a few minutes, and just one time. The road vehicle's payload is shocked by every pot hole and speed bump, for years.
tqi
18 hours ago
Isn't the problem also that because of radiation, processors in space either need to have larger feature sizes OR additional shielding / redundancy? Seems like a pretty high price to pay for slightly cheaper energy...
nijave
17 hours ago
Ars had an article that cited some HPE testing on the international space station that said regular hardware is _probably_ fine up to about 5 years
Definitely not definitive but it's plausible current hardware could survive with minimal modification
tqi
17 hours ago
hm but "fine" as in probably won't die?
my question was more whether the hardware would need extra redundancy or shielding in order to not have unacceptably high error rates
nijave
17 hours ago
There's a radiation section in the article, I'll let you draw your own conclusions
https://arstechnica.com/space/2026/07/how-hard-is-it-to-buil...
onli
18 hours ago
No. It really is a scam. Everyone with understanding of the physics involved wrote so. Heat dissipation + radiation + launch cost make it a no-go.
markasoftware
18 hours ago
Heat dissipation isn't as big a concern as it seems: the weight of the solar panels is significantly larger than that of the heatsinks you'd need per typical modern gpu
rtkwe
2 hours ago
It's not just the weight some outside groups have done the calculations and to dissipate the heat at the operating temperatures in the white paper without a heat pump to increase the radiator temp and thus efficiency requires a massive pump that would have to move nearly 69,000 kg of coolant per second continuously without fail.
olyjohn
18 hours ago
The cooling is not an issue for their current designs. Look at their AI1 Satellite specs. They clearly have the cooling figured out. The thing is that it's not a datacenter, it's a single rack. A single rack that weighs multiple tons.
You can figure out the weight of the thing based on the total power output, and "power to weight ratio" from SpaceX's own diagrams. Then look up how much it costs to launch per ton, and even look up what they are projecting it will cost with Starship. Even if they get costs down, it's still astronomical. I just can't figure out who would pay that much money to put a rack into space. There's no way the power savings are worth it. Unless you have some niche where you need your workload in space, I can't see the value at all.
nickff
18 hours ago
SPCX is valued as an AI company; any and all issues you have with AI company valuations apply to to SPCX.
I too agree that SPCX’s space business is real and valuable, but it’s (almost completely) irrelevant here.
dragontamer
18 hours ago
Because SpaceX bought xAI/Twitter.
All of the losses are from the xAI/Twitter side of the house. And Elon Musk needs a flimsy story so that no one sues him. It doesnt have to be a believable story, it just needs to be enough so that no lawyer cares to bring a case in Texas vs SpaceX and Elon for breach of fiduciary duty.
The story did its job. Elon offloaded the money losing Twitter/xAI out of his personal wealth and onto the public through SpaceX. Done and done. SpaceX is now an AI company (or contains one) and needs to perform as such.
-------
It's literally the same story as Tesla/Solar City. Make up bullshit about solar panel synergy with EVs and buy out his cousins failing company. Make it TSLA shareholders problem for figuring out how to make a profit from the failing company, it's no longer Kimball Musks concern since the buyout
tmp10423288442
17 hours ago
The ocean is worse than space from every perspective but cooling, radiation shielding, and cost/ease of installation. But that just highlights how bad of an idea space-based data centers are at this time.
metalliqaz
17 hours ago
> from every perspective but cooling, radiation shielding, and cost/ease of installation.
Oh is that all? Those are major data center concerns.
Don't forget the biggest one: an ocean-based system could be pulled up and serviced without the need for a human-rated rocket. Oh, and bandwidth/latency.
The ONLY benefit of space is that it doesn't require siting a major construction in a town full of angry residents, and it has abundant solar power. But given how much it costs to get the solar panels in orbit, that power sure ain't free.
tmp10423288442
13 hours ago
The ocean poses two major threats to any construction - water pressure and corrosion.
eldenring
17 hours ago
Cooling is relatively easy, you just need radiators which are passive, and essentially reduce to a launch cost penalty. You are right that they can't be serviced, but that is missing the point of orbital data centers. The whole point is that you can build hundreds of thousands of these in a factory and launch them in a scalable manner. The power, cooling, etc. comes for "free". In the long run, as the cost of the chip, launches, etc. goes down, orbital data centers will scale better terrestrial ones.
As a side note, I don't understand why I keep seeing these wrong arguments on HN repeatedly. Like everything mentioned in this thread can easily be fact checked. Radiative cooling is solved, launch costs are going down, so power costs will pay themselves back very quickly, etc.
You can argue about specifics, like chips will get more sophisticated + power efficient and fabrication will be the true longterm bottleneck, or SMRs/fusion could reduce energy bottlenecks, but talking about cooling as if convective cooling is the only option is just nonsensical.
lifeisstillgood
16 hours ago
My back of the envelope maths:
Suns energy at ISS is about 1.4KW/m2 Solar panels about 35% efficient but let’s say 50% for fun
700w/m2, or about one H100 worth per sq metre (hey, I could run my own H100 off a roof top panel !!)
We want a small 70MW data centre - which is 100,000 times the size so 100,000 m2 or an array 316mx316m or 15 football pitches
Then as it’s energy in and energy out you need radiators on dark side of same size
The ISS is ~ 2000m2, so that’s fifty ISSes
I mean it’s physically possible. But the engineering, the space launch costs they are staggering. And the upside is … Im not sure
All the win seems to be is free sun energy, but a data centre in Texas or Nigeria just needs about twice the solar panels and some big ass batteries.
Im not costing that out but, honestly it seems like a marketing pitch or a really obscure need to put compute beyond the reach of governments.
groby_b
17 hours ago
"you just need radiators which are passive
"Just" is doing a lot of work there. SpaceX is planning to launch 100 GW of compute annually, that comes with ~ 2.5 square kilometers of radiator (assuming an optimistic 800K radiator temp and emissivity of 0.9, double sided)
Go for advanced carbon composites, you can do that with just 5,000 metrics tons or so of material. That's 34 starship launches just for the radiators. We haven't solved assembly, we haven't brought up power panels or core compute. Planned launch cadence that SpaceX hopes to reach end of this year: 12/year.
spongebobstoes
16 hours ago
radiators about the same size and weight as solar panels will do the trick
there is already a h100 in orbit
1GW of compute is a lot in 2026. comparing 100GW of annual compute to SpaceX 2026 goals does not make sense
if Starship launch cost predictions are accurate, data centers in space will happen within 10 years
croes
16 hours ago
> The numbers are brutal. Starcloud’s own white paper estimates that a two-sided radiator held around 20°C would emit only about 633 watts per square meter, over 1,000 times slower than water cooling of AI chips on Earth. So, a puny 1-megawatt orbital data centre, 1,000 times smaller than the gigawatt scale of hyperscale data centres on Earth, would need about 1,600 square meters of radiator, an area roughly the size of a hockey rink.
1GW needs a pretty big area for radiation.
And in space your data centers is hard to defend against foreign actors
spongebobstoes
16 hours ago
chips run way hotter than 20C, and radiative cooling scales to the fourth power of temperature. check the math
CamperBob2
15 hours ago
The whole point is that you can build hundreds of thousands of these in a factory and launch them in a scalable manner. The power, cooling, etc. comes for "free". In the long run, as the cost of the chip, launches, etc. goes down, orbital data centers will scale better terrestrial ones.
How is this not true for terrestrial/ocean deployment as well? It will ALWAYS be easier to shed heat on Earth than it will be in orbit. Convection, conduction, radiation... in space, you only get the last one.
So take the same unattended hardware you were going to launch into orbit, and put it on a container ship instead. You'll be better off in every way. If it makes you feel better, lie and tell everyone that you launched it into space. Building orbit-capable data centers might make sense, but actually launching them never will.
croes
16 hours ago
> Radiative cooling is solved,
By that logic, climate change is also solved, just built a giant radiator.
metalliqaz
17 hours ago
> Radiative cooling is solved.
This is emphatically not true at any scale in which this scheme makes sense. Be careful with including too many Musk boosters in your information diet.
Mawr
15 hours ago
> and essentially reduce to a launch cost penalty.
Are you arguing that all this is technically possible or something? The whole point is that the costs would dwarf the gains.
> You are right that they can't be serviced, but that is missing the point of orbital data centers.
Pointing out a downside of something isn't ever "missing the point".
> The whole point is that you can build hundreds of thousands of these in a factory
In an Earth-based factory, right? Am I to understand that we can't build hundreds of thousands of regular Earth-based datacenters in a factory?
> and launch them in a scalable manner.
Wanna bet that launching something to space will always be a few orders of magnitude more expensive than shipping it somewhere across the planet?
> The power, cooling, etc. comes for "free".
Unlike on Earth, where you pay for sunshine? Or is cooling "free" in space but not on Earth? Lol?
> In the long run, as the cost of the chip, launches, etc. goes down, orbital data centers will scale better terrestrial ones.
The costs of the chips will get lower in space than on Earth?
The costs of launches will, again, become cheaper than terrestial transport?
> As a side note, I don't understand why I keep seeing these wrong arguments on HN repeatedly. Like everything mentioned in this thread can easily be fact checked. Radiative cooling is solved, launch costs are going down, so power costs will pay themselves back very quickly, etc.
The question isn't whether this is physically possible, but why you'd want to do it instead of an Earth-based datacenter. It's all downsides basically.
tim333
5 hours ago
Paul Graham has been positive about the YC startup doing data centers in space https://x.com/paulg/status/2009686627506065779
For the idea to make sense I think you have to project forward some years to launches being cheaper and compute demand outrunning the energy grid.
johneth
5 hours ago
What makes you think Paul Graham knows what he's talking about re: space, data centers, and the logistics of lifting data centers into space and the ongoing maintenance of them. I don't understand the deification his thoughts receive around here.
paxys
14 hours ago
For something to be a viable product it has to solve a problem. What problems are data centers in space solving? I can't think of a single one.
techgnosis
14 hours ago
No noise pollution or actual pollution from gas turbines. No using water in the desert. No angry communities.
paxys
13 hours ago
None of these are problems if you put data centers far away from population. No one does that right now because it's a lot more expensive to set up and maintain, because you have to set up all the infrastructure from scratch. You know what's 10000x more expensive than that? Setting up the infrastructure in space.
tootie
13 hours ago
Like much new technology, it evades regulations. Hyperscalers are getting crushed by popular backlash and resource constraints. And like typically nerds they'd rather dream up a massively overengineered solution rather than face their responsibility as human beings.
doctoboggan
18 hours ago
> Is there anyone credible who thinks this is a plausible pathway for SpaceX to make huge amounts of profit?
Scott Manly (who I think is credible) has a video where he goes over the logistics of SpaceX's space based data centers. He seems to think its an idea worth pursuing, but its important to note that his expertise is space tech, and not business strategy.
jacobgold
18 hours ago
Yeah, I have no doubt that it's possible to put GPU servers in space. The Starlink satellites are servers in space. The question is whether it's even remotely profitable to do this for AI training/inference servers.
bakies
17 hours ago
The same way that xAI has compute on the ground and there's such demand that the compute exists so it will be sold. I think SpaceX can conceivably sell the space compute easily. This goes with the business strategy of Elon which is just sell services to himself. He sells rocket launches to himself with the excuse of creating a space datacenter. The same way he sells cybertrucks to spacex because the public won't buy them. I'm pretty confident it's definitely cheaper to put the compute in Texas, but might be viable enough to sell himself rocket launches and make his company worth more to leverage for more ventures. I'm not a business person I don't really get how it's all so valuable if the only demand is itself.
nijave
17 hours ago
Training, no. Latency is too high.
Inference the latency becomes trivial.
Other things, I suspect latency is too high again.
pjscott
15 hours ago
They're going for an orbital height of 600–800 km, or about 2-3 light-milliseconds from Earth's surface. A lot of people think of satellites as being necessarily high-latency because of intuition drawn from satellites in geosynchronous orbit – but those are about 50x farther away from earth and have correspondingly longer ping times.
bakies
9 hours ago
They don't go directly to the satellite but through ground stations and then bounce around on lasers between satellites. The latency is going to be worse than fiber
FuckButtons
17 hours ago
The only barely sane rationale that I’ve heard for wanting datacenters in space is that they would give space-x low latency signal processing capacity it would need to turn Starlink into a real time Passive SAR constellation.
onion2k
18 hours ago
Richard Campbell did a great talk at NDC a month about about this - https://www.youtube.com/watch?v=eo7MEPgWGic
xtracto
16 hours ago
Too bad the things that really matter don't make "sense" (mostly people talk about economic sense when talking about this).
Increasing the temperature of the earth , and water usage are two things that using Space data centers will excel vs the alternatives. However society has just not been able to price that directly into these huge buildings.
Funny that I agree with EM idea on this, but the reasons are so far away.
leptons
18 hours ago
The only way it makes sense is if you think the massive job losses due to AI will lead to people burning down datacenters on earth. An older spec'd and unmaintainable datacenter is worth way more than one in ashes.
pphysch
18 hours ago
Datacenters in Antarctica or deep ocean also fulfill that.
WalterBright
17 hours ago
> Data centers submerged in the ocean
Sooner or later it's going to leak.
abfan1127
17 hours ago
I think corrosion is the big issue here. perhaps that is where the leak comes from.
WalterBright
17 hours ago
Water under high pressure will find any weakness. (For example, the places where the wires go in and out.)
Corrosion indeed is always a problem.
esalman
10 hours ago
> have only an enthusiast's understanding of rockets and physics, so I'm genuinely open-minded to the possibility.
I used to be open minded too but lost all sense of credibility in anything Elon Musk touches when he called nanotechnology a pseudoscience. Since then it's only been downhill. One does not have to be subject matter expert, even China is vertically landing rockets now.
deaton
17 hours ago
To me it feels like a way for Musk to justify directing AI money towards his first true love, which was space.
RIMR
18 hours ago
Let's just put it this way:
The ISS produces about 120 kilowatts of electricity.
An Nvidia Blackwell B200 GPU uses 1.2 kilowatts of electricity.
So, you would need a similar array of solar panels and radiators just to power 100 of them. You probably would need 2-3 launches for a satellite this big, and realistically, you would just make smaller satellites.
That's $4,000,000 worth of GPUs, A couple millon or more of RAM, SSDs, etc., a radiation-proof satellite housing to support all of that hardware, solar arrays, launch costs ($74M per Falcon launch), all for maintenance to be impossible and the hardware to become obsolete in a couple of years.
It's a delusion unless we invent some way to go to space for free.
LorenDB
18 hours ago
SpaceX would be launching these on Starship, which has a much lower targeted launch cost.
RIMR
17 hours ago
For reasons already outlined, I have doubts about their math. Targeting $250/kg payload costs is ambitious for a rocket that has not yet successfully reached orbit or proven cost-effective.
Even if we do somehow succeed at affordably dumping tons of GPUs into orbit, what do we do about the Kessler Syndrome?
fittingopposite
6 hours ago
From first principles, does anyone know what the minimum costs are to put a rocket into space? There must be a minimum cost given that the rocket engines have to thrust until reaching escape velocity to get you to space.
AnthonyMouse
17 hours ago
I don't really get the obsolete argument.
The thing has two main parts. One, a bunch of solar panels, shielding and radiators. This the heavy / expensive to launch part, but should last for what, decades? Two, a bunch of GPUs/servers. These become obsolete, but so what? They're not that heavy, so every few years you send up another rocket and swap them out.
asadotzler
17 hours ago
Launches are not $74M. That's retail pricing.
SpaceX's launch cost, the internal spend to put one Falcon 9 Starlink payload in orbit, with a return to launch site booster recovery, is about $15M.
If you're going to make such assertions, do the legwork to make sure your numerical claims aren't off by 500%.