Data centers in space makes no sense
201 points - yesterday at 7:37 PM
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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.
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.
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.
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.
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.)
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.
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.
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.
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.
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.
And hardware that is happy in high-radiation environments is not going to be fast.
what am I missing here?
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!
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.
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.
- 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
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.
As an alleged human, I'd like to preserve my option to interfere.
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?
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.
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.
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
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.
- 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.
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.
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.)
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
Just do the basic thermal heat transfer math.
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.
(If you can't xcancel it yourself your hacker card is revoked.)
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.
"That Musk guy is so naive to think you can put data centers in space, what a doof".
Similar comments were probably made regarding electric cars, reusable rockets, buying Twitter, and so on.
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.