Yes cooling is difficult. Half the "solar panels" on the ISS aren't solar panels but heat radiation panels. That's the only way you can get rid of it and it's very inefficient so you need a huge surface.
This isn’t true. The radiators on ISS are MUCH smaller than the solar panels. I know it’s every single armchair engineer’s idea that heat rejection is this impossible problem in space, but your own example of ISS proves this is untrue. Radiators are no more of a problem than solar panels.
The radiators are significantly smaller than the PV arrays, but not by a massive ratio; looks like about 1:3.6 based on the published area numbers that I could find.
It looks like the ISS active cooling system has a maximum cooling capacity that could handle the equivalent of a single-digit number of racks (down to 1 for an AI-focused rack).
The heat load of the ISS is a handful of astronauts and some equipment and whatever it absorbs from the sun. Not an entire data center or a nuclear rocket which is where the radiator discussion comes into play.
The heat load is equal to the load from the solar panels, to first order. So actually yeah, you CAN compare the size of solar panels to the size of the radiators.
seems oddly paradoxical. ISS interior at some roughly livable temperature. Exterior is ... freakin' space! Temperature gradient seems as if it should take of it ...
... and then you realize that because it is space, there's almost nothing out there to absorb the heat ...
There's nothing paradoxical about it. There's no such thing as a temperature gradient in a vacuum, there's nothing to hold or measure temperature against. And thus a vacuum is a really good insulator. Which is why a vacuum flask, which ultimately became one of Thermos' most well known products, is used to control temperature both in and outside the lab.
Except a thermos has a really low emissivity, otherwise (if it had high emissivity), it’d be a poor insulator due to thermal radiation, the same reason why ISS’s radiators are much smaller than its solar panels.
I’d settle for at least a high school physics education. This idea seemed insane when I first heard about it a few weeks back. This analysis just makes it that much more crazy.
If YC is hell bent on lighting piles of money on fire, I can think of some more enjoyable ways.
Radiation is not actually a problem unless you're trying to do super high power nuclear electric propulsion (i.e. in your videogame). Classic armchair engineer mistake, tbh.
Radiators work great in space. Stefan-Boltzmann's law. The ISS's solar panels are MUCH smaller than the radiators. Considering datacenters on Earth have to have massive heat exchangers as well, I really think the bUt wHaT aBoUt rAdiAtOrs is an overblown gotcha, considering every satellite still has to dump heat and works just fine.
The problem is not that radiators don't work. The problem is the need for liquid cooling. The heat prduced per area in the GPU/CPU is much bigger than the cooling capacity per area of your radiator.
Even here on earth, contemporary GPU racks for AI have had to move to liquid cooling because it is the only way to extract enough heat. At 120 kW for 18x 1U servers (GB200 NVL72), the power density is waaay beyond what you can do with air even.
The last time Starcloud was doing the rounds on HN, I estimated that they need to be pumping water at a flow rate of 60 000 liters per second, if you use the numbers in their whitepaper. That's a tenth of the Sacramento river, flowing in space through a network with a million junctions and hoping nothing leaks.
The point is: the power consumption requirements (quote: considering every satellite still has to dump heat and works just fine) for satellite X is not even close to racks of hyperscaler compute.
A great interactive example of this is the game Oxygen Not Included. By the late game, you're biggest problem is your base getting too hot from the waste heat of all your industry.
If you read the Starcloud whitepaper[1], it claims that massive batteries aren't needed because the satellites would be placed in a dawn-dusk sun-synchronous orbit. Except for occasional lunar eclipses, the solar panels would be in constant sunlight.
The whitepaper also says that they're targeting use cases that don't require low latency or high availability. In short: AI model training and other big offline tasks.
For maintenance, they plan to have a modular architecture that allows upgrading and/or replacing failed/obsolete servers. If launch costs are low enough to allow for launching a datacenter into space, they'll be low enough to allow for launching replacement modules.
All satellites launched from the US are required to have a decommissioning plan and a debris assessment report. In other words: the government must be satisfied that they won't create orbital debris or create a hazard on the ground. Since these satellites would be very large, they'll almost certainly need thrusters that allow them to avoid potential collisions and deorbit in a controlled manner.
Whether or not their business is viable depends on the future cost of launches and the future cost of batteries. If batteries get really cheap, it will be economically feasible to have an off-the-grid datacenter on the ground. There's not much point in launching a datacenter into space if you can power it on the ground 24/7 with solar + batteries. If cost to orbit per kg plummets and the price of batteries remains high, they'll have a chance. If not, they're sunk.
I think they'll most likely fail, but their business could be very lucrative if they succeed. I wouldn't invest, but I can see why some people would.
> For maintenance, they plan to have a modular architecture that allows upgrading and/or replacing failed/obsolete servers. If launch costs are low enough to allow for launching a datacenter into space, they'll be low enough to allow for launching replacement modules.
This is hiding so, so much complexity behind a simple hand wavy “modular”. I have trained large models on thousands of GPUs, hardware failure happen all the time. Last example in date: an infiniband interface flapping which ultimately had to be physically replaced.
What do you do if your DC is in space? Do you just jettison the entire multi million $ DGX pod that contains the faulty 300$ interface before sending a new one? Do you have an army of astronauts + Dragons to do this manually? Do we hope we have achieve super intelligence by then and have robots that can do this for us ?
Waving the “Modular” magic key word doesn’t really cut it for me.
> Whether or not their business is viable depends on the future cost of launches and the future cost of batteries. If batteries get really cheap, it will be economically feasible to have an off-the-grid datacenter on the ground. There's not much point in launching a datacenter into space if you can power it on the ground 24/7 with solar + batteries.
Something tells me that the price of batteries is already cheap enough for terrestrial data centers to make more economic sense than launching a datacenter - which will also need batteries - into space.
The cheapest batteries today are around $100/kWh. Optimistically assuming 12 hours of sunlight per day, a 40MW datacenter would need 480MWh of batteries to cover the dark period, costing $50 million. Realistically you'd need at least 16 hours worth of batteries to cover winter months when the night is longer, raising your battery costs to $65 million. You'd also need ≈5x more solar panels than in space, and these panels would be more expensive due to shielding from weather. 120MW of ground-based solar panels would cost around $100 million.
Assuming the $165M of panels and batteries last for a decade, and there are no maintenance costs, they'll provide 3,504,000MWh over that time for an energy cost of 4.7 cents per kWh. This is competitive with grid power in some places. It also has the advantage of not needing backup generators. But maintenance costs do exist, and it makes more financial sense to buy power as you use it rather than pay upfront.
> Optimistically assuming 12 hours of sunlight per day, a 40MW datacenter would need 480MWh of batteries to cover the dark period, costing $50 million.
A 40MW data center doesn't run constantly at 40MW. That's its load rating. Like any industrial facility, actual peak loads are probably around 80% and average loads are lower.
Also, why do you assume that the data center has to be off-grid? That's a constraint of a space-based datacenter, not a ground based datacenter.
Datacenters with storage can complement grid power.
> The cheapest batteries today are around $100/kWh.
If we are comparing ground based data centers to hypothetical space based ones, then consider that grid scale iron air batteries are coming soon at $20/kWh.
You quoted me saying, "There's not much point in launching a datacenter into space if you can power it on the ground 24/7 with solar + batteries." and suggested, "...that the price of batteries is already cheap enough for terrestrial data centers to make more economic sense than launching a datacenter." So I replied with some napkin calculations estimating the cost of powering a datacenter 24/7 with current solar + batteries. You could assume those solar panels and batteries are on the grid, allowing excess capacity to be sold to others, but then you need another $20 million for backup generators.
I assumed the battery + solar setup would need to provide 40MW because while datacenters usually do run below capacity, you'd also want some extra capacity to account for cooling systems, battery/panel degradation, and the fact that for some tasks (such as AI training), you actually do get close to 100% capacity for long periods of time. Feel free to cut my numbers by 20%, but I don't think that would change the bottom line: off-grid datacenters could be cost competitive in some regions, but the upfront costs don't make them worthwhile right now. If battery costs go down (as I hope they will), that will likely change.
An orbital datacenter would not need significant batteries because it would be placed in a dawn-dusk sun-synchronous orbit. The panels would only be occluded during solar eclipses, which in low earth orbit last a few seconds. Starcloud is betting that launch costs will plummet but battery costs will not, and that they'll be able to cheaply solve space-specific issues related to cooling, maintenance, and reliability.
If you look at my other comments in this thread, you'll see I predict they will fail. A lot of people are coming to the same conclusion, but for mistaken reasons (eg: thinking that space-based datacenters would need as many batteries as ones on the ground). I'm just trying to correct that.
> If you look at my other comments in this thread, you'll see I predict they will fail.
Yep, we agree on that.
> off-grid datacenters could be cost competitive in some regions, but the upfront costs don't make them worthwhile right now.
I still don't understand why the alternative to space based datacenters being proposed is off-grid datacenters.
Why not compare it to grid-connected datacenters with enough behind the meter generation and storage to avoid peak grid prices? After all the ultimate comparison metric is cost (and ideally C02 emissions)
Hydrogen fuel cell vehicles are a little different because there are safety, economic, and physical constraints that mean they will always be worse than battery electric or gas cars. I and many others correctly predicted this.[1] For hydrogen to succeed, batteries would have to get more expensive and/or have worse energy density than they did in 2015.
Satellite data centers seem unlikely to me, but at least their feasibility doesn't require that existing stuff get more expensive/worse. Starcloud is a bet that three things will happen in the next decade:
- SpaceX Starship will succeed and drastically reduce launch costs.
- Batteries will not get 10x cheaper.
- There will be valuable applications for high latency, high performance compute (eg: AI training).
If any one of these things does not happen, Starcloud is doomed (or will have to pivot). If they all happen, Starcloud has a chance at success.
International space law (starting with the Outer Space Treaty of 1967) says that nations are responsible for all spacecraft they launch, no matter whether the government or a non-governmental group launches them. So a server farm launched by a Danish company is governed by Danish law just the same as if they were on the ground- and exposed to the same ability to put someone into jail if they don't comply with a legal warrant etc.
This is true even if your company moves the actual launching to, say, a platform in international waters- you (either a corporation or an individual) are still regulated by your home country, and that country is responsible for your actions and has full enforcement rights over you. There is no area beyond legal control, space is not a magic "free from the government" area.
They don't need to do that if they go after your ground station operators.
To escape the law you need to hide or protect something on earth (your ground station(s), downlinks). If you can hide or protect that infrastructure on earth, why bother putting the computers in space?
I'm not sure how you maintain hidden ground stations while providing a commercial service that justifies many $MM in capital and requires state support to get launch permission.
> I'm not sure how you maintain hidden ground stations while providing a commercial service that justifies many $MM in capital and requires state support to get launch permission.
Who said that Starcloud's business model is about commercial services? At https://news.ycombinator.com/item?id=44397026 I rather speculate that Starcloud's business model is about getting big money defense contracts.
What if you’re a stateless person? (Not an easy status to acquire these days, but any US citizen can just renounce their citizenship without getting a new one, for example.)
nations are responsible for all spacecraft they launch, no matter whether the government or a non-governmental group launches them.
Nations come and go. In my lifetime, the world map has changed dozens of times. Incorporate in a country that doesn't look like it's going to be around very long. More than likely, the people running it will be happy to take your money.
Those kinds of countries don't tend to be the kinds of countries with active space programs.
And more critically - they have successor states.
The Russian Federation is treated as the successor to the USSR in most cases (much to the chagrin of the rest of the CIS) and Serbia is treated as the successor to Yugoslavia (much to the chagrin of the rest)
That is not how international law works, you don't get to say "we are a new country and therefore not bound by treaties that earlier forms did."
This principle was established when Nazis were convicted for war crimes at Nuremburg for violating treaties that their predecessor state the Weimar Republic signed, even after the Nazi's repudiated those treaties and claimed they were signed by an illegitimate state, and that they were a new Reich, not like the Wiemar Republic.
Basically if territory changes hand to an existing state that state will obviously still have obligations, and if a new state is formed, then generally it is assumed to still carry the obligations of the previous state. There is no "one weird trick" to avoid international law. I assure you that the diplomats and lawyers 80 years ago thought of these possibilities. They saw what resulted from the Soviet and Nazi mutual POW slaughters, and set up international law so no one could ignore it.
The 'Principality of Sealand', anywhere else on the high seas or Antarctica have their issues with practicality too, but considerably less likelihood of background radiation flipping bits...
:-) I appreciate your snark and the ad campaign reference.
But if international waters isn't enough (and much cheaper) then I don't think space will either. Man's imagination for legal control knows no bounds.
You wait (maybe not, it's a long wait...), if humankind ever does get out to the stars, the legal claims of the major nations on the universe will have preceded them.
Unless the company blasts its HQ and all its employees into space, no, they are very much subject to the jurisdiction of the countries they operate in. The physical location of the data center is irrelevant.
[Mild spoilers for _Critical Mass_ by Daniel Suarez below]
> Servers outside any legal jurisdiction
Others have weighed in on the accuracy of this, with a couple pointing out that the people are still on the ground. There's a thread in _Critical Mass_ by Daniel Suarez that winds up dealing with this issue in a complex set of overlapping ways.
Pretty good stuff, I don't think the book will be as good as the prior book in the series. (I'm only about halfway through.)
I know there's the fantasy of orbital CSAM storage able to beam obscenity to any point on the ground with zero accountability, but that is not going to survive real world politics.
>Shooting down a satellite is a major step that creates a mess of space junk, angering everybody.
unless everybody is angry at satellite in which case it is a price everybody is even eager to pay.
>Plus you can just have a couple of politicians from each major power park their money on that satellite.
I've long had the idea that there are fashions in corruption and a point at which to be corrupt just becomes too gauche and most politicians go back to being honest.
This explains the highly variant history of extreme corruption in democracies.
At any rate while the idea that the cure for any government interference is to be sufficiently corrupt sounds foolproof in theory I'm not sure it actually works out.
If I was a major politician and you had my competitors park their money on your satellite it would become interesting for me to get rid of it. Indeed if you had me and my competitors on the satellite I might start thinking how do I conceal getting my money out of here and then wait for best moment to ram measure through to blow up satellite.
I'm sorry but what logic is it you're referring to here? Is it the idea that there are fashions in corruption? If so by that logic we are probably in an era of high corruption.
Is it the idea that if I were a corrupt politician and I had equally corrupt enemies I would use my knowledge of their corruption to dirty trick them? Because ... dirty tricking them and getting them to lose all their finance at one time is not quite the same as passing a law making it difficult for everyone to get more finance from hereon out.
I'm not following exactly what logic of mine you think you've defeated with observing that there are a lot of corrupt politicians nowadays?
The best argument I've heard for data centres in space startups is it's a excuse to do engineering work on components other space companies might want to buy (radiators, shielding, rad-hardened chips, data transfer, space batteries) which are too unsexy to attract the same level of FOMO investment...
Yes, and also just because a space data center isn’t useful today doesn’t mean it won’t be required tomorrow. When all the computing is between the ground and some nearby satellites, of course the tradeoffs won’t be worth it.
But what about when we’re making multi-year journeys to Mars and we need a relay network of “space data centers” talking to each other, caching content, etc?
We may as well get ahead of the problems we’ll face and solve them in a low-stakes environment now, rather than waiting to discover some novel failure scenario when we’re nearing Mars…
We'd build it then? The problems of a space data center are extremely generic and only worth solving when you actually need one. Which would never be in low earth orbit.
> what about when we’re making multi-year journeys to Mars and we need a relay network of “space data centers” talking to each other, caching content, etc?
How would this work? Planets orbit at different speeds, so you can't build a chain of relays to another planet. I can imagine these things orbiting planets, but is that worth it compared to ground-based systems?
You need less batteries in orbit than on the ground since you're only in shade for at most like 40 minutes. And it's all far more predictable.
Cooling isn't actually any more difficult than on Earth. You use large radiators and radiate to deep space. The radiators are much smaller than the solar arrays. "Oh but thermos bottles--" thermos bottles use a very low emissivity coating. Space radiators use a high emissivity coating. Literally every satellite manages to deal with heat rejection just fine, and with radiators (if needed) much smaller than the solar arrays.
Latency is potentially an issue if in a high orbit, but in LEO can be very small.
Equipment upgrades and maintenance is impossible? Literally, what is ISS, where this is done all the time?
Radiation shielding isn't free, but it's not necessarily that expensive either.
Orbital maintainence is not a serious problem with low cost launch.
The upside is effectively unlimited energy. No other place can give you terawatts of power. At that scale, this can be cheaper than terrestrially.
> The radiators are much smaller than the solar arrays.
Modern solar panels are way more efficient than the ancient ones in ISS, at least 10x. The cooling radiators are smaller than solar panels because they are stacked and therefore effectively 5x efficient.
Unless there are at least 2x performance improvements on the cooling system, the cooling system would have to be larger than solar panels in a modern deployment.
This is false. It’s pretty straightforward to prove using Stefan-Boltzmann. Radiating from both sides at 300K, a square radiator that’s 1 meter on a side emits 920W.
Additionally, you wouldn’t use cutting edge 35% triple junction cells for a space datacenter, you’d use silicon cells like Starlink and ISS use. 22% efficient with 90% full factor, given 1350W/m^2 and thus 270W/m^2, to provide enough power for that radiator you’d need a solar panel 3.4 times as big, and that’s if you were in 24/7 sunshine. If you’re in a low orbit that’s obscured almost half the time, it’s 6-7 times as big.
Why do people keep making these obviously wrong claims when a paragraph of arithmetic shows they’re wrong? Do the math.
Re: reliable energy. Even in low earth orbit, isn't sunlight plentiful? My layman's guess says it's in direct sun 80-95% of the time, with deterministic shade.
It's super reliable, provided you've got the stored energy for the reliable periods of downtime (or a sun synchronous orbit). Energy storage is a solved problem, but you need rather a lot of it for a datacentre and that's all mass which is very expensive to launch and to replace at the end of its usable lifetime. Same goes for most of the other problems brought up
Exactly this. It's not that it's a difficult problem, but it is a high mass-budget problem. Which makes it an expensive problem. Which makes it a difficult problem.
That would make communicating with bits on Earth kind of painful though; I suppose that would work for a server that serves other sun-synchronous objects, but that seems like a rather small market.
If starcloud integrated with something like starlink, using the laser inter satellite links to distribute ground comms across a network of satellites, then the datacenter maintaining a direct link to a base station is probably a non-issue for most purposes.
We’re probably thinking of it the wrong way. Instead of a single datacenter it’s more likely we build constellations and then change the way we write software.
There will probably be a lot more edge computing in the future. 20 years ago engineers scoffed at the idea of deploying code into a dozen regions (If you didn’t have a massive datacenter footprint) but now startups do it casually like it’s no big deal. Space infrastructure will probably have some parallels.
That sounds like the Guoxing Aerospace / ADA Space “Three-Body Computing Constellation”, currently at 12 satellites (out of a planned 2,800).
The Chinese project involves a larger number of less powerful inference-only nodes for edge computing, compared to Starcloud's training-capable hyperscale data centers.
> 20 years ago engineers scoffed at the idea of deploying code into a dozen regions (If you didn’t have a massive datacenter footprint) but now startups do it casually like it’s no big deal.
Are there many startups actually taking real advantage of edge computing? Smaller B2B places don't really need it, larger ones can just spin up per-region clusters.... and then for 2C stuff you're mainly looking at static asset stuff which is just CDNs?
Who's out there using edge computing to good effect?
You're making lots of assumptions. They can put like 1000 Raspberrypi's which don't need all that much cooling and relatively little energy requirements.
For your other concerns, the risks are worth it for customers because of the main reward: No laws or governments in space! Technically, the datacenter company could be found liable but not for traffic, only for take-down refusals. Physical security is the most important security. For a lot of potential clients, simply making sure human access to the device is difficult is worth data-loss,latency and reliability issues.
Reliable energy? Possible, but difficult -- need plenty of batteries
Cooling? Very difficult. Where does the heat transfer to?
Latency? Highly variable.
Equipment upgrades and maintenance? Impossible.
Radiation shielding? Not free.
Decommissioning? Potentially dangerous!
Orbital maintenance? Gotta install engines on your datacenter and keep them fueled.
There's no upside, it's only downsides as far as I can tell.