Particularly I wonder how you would shed all that heat in a vacuum? I keep seeing arguments that the cold of space would make data centers easier to cool, but this totally contradicts my observation that all the spacecraft I’ve read about have dedicated systems to shed excess heat produced by electronic systems, as opposed to, say, having dedicated heating systems for life support and never having to worry about electronic systems generating excess heat because the cold of space just takes care of it? E.g. Apollo as I understand it mostly relied on the waste heat of systems dedicated to other functions, the Apollo 13 crew only had to worry about cold because they eliminated virtually all sources of waste heat simultaneously to conserve electricity. I think Apollo’s only dedicated systems for cabin temperature control were actually cooling systems. And this totally wouldn’t apply in the data center scenario.
Yes, I’ve worked on spacecraft and you have to put about as much effort into dissipating your energy as collecting it. The benefits I’ve heard claimed for space based compute are minor at best, and the economic downsides of cooling are show-stopping before even considering the (many) other negatives. Electronics also have to run much hotter than otherwise if your only cooling method is radiation. I’m honestly struggling to understand why some people that I normally consider reasonable and realistic are giving it much consideration.
It’s not that complex in principle: you use really big radiators.
If you look at https://www.starcloud.com/’s front page video, you see exactly that. What might look like just a big solar array is actually also a big radiator.
AFAICT it’s one of those things that works in principle but not in practice. In theory you can make really cheap space solar and radiator arrays, and with full reuse launch can approach the cost of propellant. In practice, we’re not even close to that, and any short term bet on it is just going to fail.
Skimming Starcloud’s whitepaper: They say the radiators are “held at 20 C” without mentioning at all how they’d actually do that. For effective heat distribution you need fluid and small tubes, which are very prone to micrometeorite impacts, which means you need a lot more shielding mass. If you don’t have effective heat distribution your chips get too hot.
We have lots of examples of radiators in space (because it’s approximately the only thing that works), and AFAIK micrometeor impacts haven’t been a dealbreaker when you slightly overprovision capacity and have structural redundancy. I don’t expect you’d want to spend too much on shielding, personally.
Not trying to claim Starcloud has a fully coherent plan, ofc.
Seems relevant post AGI/ASI (human labor is totally obsolete and AIs have massively increased energy output) maybe around the same point as when you’re starting to build stuff like Dyson swarms or other massive space based projects. But yeah, IMO probably irrelevant in the current regime (for next >30 years without AGI/ASI) and current human work in this direction probably doesn’t transfer.
I think the case in favor of space-based datacenters is that energy efficiency of space-based solar looks better: you can have perfect sun 100% of the time and you don’t have an atmosphere in the way. But, this probably isn’t a big enough factor to matter in realistic regimes without insane amounts of automation etc.
One argument is that energy costs 0.1 cents per kWh versus 5 cents on Earth. For now launch costs dominate this but in the future this balance might change.
I wish that article included any justification for that argument and I was unable to find any elsewhere by Chris Stott. Space energy today is certainly far more expensive than earth energy, probably 1000x.
Even as launch costs approach 0, things that can operate in space are more expensive than not. Vastly more difficult maintenance and cooling, radiation hardening, latency… I don’t see how even 7x cheaper energy per area (current solar is ~200 W/m^2 avg, space maximum is 1360 W/m^2) can make up for those things. (edit: this accounts for weather + night + atmosphere effects, see below comment)
In addition to hitting higher energy from a given area, you also can get the same energy 100% of the time (without issues with night or clouds). But yeah, I agree, and I don’t see how you get 50x efficiency even if transport to space (and assembly/maintenance in space) were free.
I agree that even with free launch and no maintenance costs, you still don’t get 50x. But it’s closer than it looks.
On Earth, to get reliable self-contained solar power we need batteries that cost a lot more than the solar panels. A steady 1 kW load needs on the order of 15 kW peak-rated solar panels plus around 50 kW-hr battery capacity. Even that doesn’t get 99% uptime, but enough for many purposes and it is probably adequate when connected to a continent-spanning grid with other power sources.
The same load in orbit would need about 1.5 kW peak rated panels and less than 1 kW-hr of battery capacity for uptime dependent only upon reliability of equipment. The equipment does need to be designed for space, but doesn’t need to be sturdy against wind, rain, and hailstones. It would have increased cooling costs, but transporting heat (e.g. via coolant loop) into a radiator edge-on to the Sun will be highly effective (on the order of 1000 W/m^2 for a radiator averaging 35 C).
This is what I was talking about, I should have been more clear. Year-average daily ground irradiance in the US seems to be about 4-5 kWh/m^2 (this includes night + weather + atmosphere effects, does not include panel efficiency) ~= 200 W/m^2. In space (assuming sun-synchronous or non-LEO, which are both more expensive than LEO) you get 1361 W/m^2. So about 7x. In the Sahara Desert it’s ~300 W/m^2 so ground-solar worst case is 4-5x.
There is a recent intense interest in space-based datacenters.
I see almost no economic benefits to this in the next, say, 3 decades and see it as almost a recession indicator in itself.
However, it could allow the datacenter owners significantly less (software) scrutiny from regulators.
Are there any economic arguments I’m missing? Could the regulator angle be the real unstated benefit behind them?
Particularly I wonder how you would shed all that heat in a vacuum? I keep seeing arguments that the cold of space would make data centers easier to cool, but this totally contradicts my observation that all the spacecraft I’ve read about have dedicated systems to shed excess heat produced by electronic systems, as opposed to, say, having dedicated heating systems for life support and never having to worry about electronic systems generating excess heat because the cold of space just takes care of it? E.g. Apollo as I understand it mostly relied on the waste heat of systems dedicated to other functions, the Apollo 13 crew only had to worry about cold because they eliminated virtually all sources of waste heat simultaneously to conserve electricity. I think Apollo’s only dedicated systems for cabin temperature control were actually cooling systems. And this totally wouldn’t apply in the data center scenario.
Yes, I’ve worked on spacecraft and you have to put about as much effort into dissipating your energy as collecting it. The benefits I’ve heard claimed for space based compute are minor at best, and the economic downsides of cooling are show-stopping before even considering the (many) other negatives. Electronics also have to run much hotter than otherwise if your only cooling method is radiation. I’m honestly struggling to understand why some people that I normally consider reasonable and realistic are giving it much consideration.
It’s not that complex in principle: you use really big radiators.
If you look at https://www.starcloud.com/’s front page video, you see exactly that. What might look like just a big solar array is actually also a big radiator.
AFAICT it’s one of those things that works in principle but not in practice. In theory you can make really cheap space solar and radiator arrays, and with full reuse launch can approach the cost of propellant. In practice, we’re not even close to that, and any short term bet on it is just going to fail.
Skimming Starcloud’s whitepaper: They say the radiators are “held at 20 C” without mentioning at all how they’d actually do that. For effective heat distribution you need fluid and small tubes, which are very prone to micrometeorite impacts, which means you need a lot more shielding mass. If you don’t have effective heat distribution your chips get too hot.
We have lots of examples of radiators in space (because it’s approximately the only thing that works), and AFAIK micrometeor impacts haven’t been a dealbreaker when you slightly overprovision capacity and have structural redundancy. I don’t expect you’d want to spend too much on shielding, personally.
Not trying to claim Starcloud has a fully coherent plan, ofc.
Seems relevant post AGI/ASI (human labor is totally obsolete and AIs have massively increased energy output) maybe around the same point as when you’re starting to build stuff like Dyson swarms or other massive space based projects. But yeah, IMO probably irrelevant in the current regime (for next >30 years without AGI/ASI) and current human work in this direction probably doesn’t transfer.
I think the case in favor of space-based datacenters is that energy efficiency of space-based solar looks better: you can have perfect sun 100% of the time and you don’t have an atmosphere in the way. But, this probably isn’t a big enough factor to matter in realistic regimes without insane amounts of automation etc.
I’ll be more inclined to believe it’s real when nvidia starts advertising the vibration tolerance of their GPUs.
One argument is that energy costs 0.1 cents per kWh versus 5 cents on Earth. For now launch costs dominate this but in the future this balance might change.
I wish that article included any justification for that argument and I was unable to find any elsewhere by Chris Stott. Space energy today is certainly far more expensive than earth energy, probably 1000x.
Even as launch costs approach 0, things that can operate in space are more expensive than not. Vastly more difficult maintenance and cooling, radiation hardening, latency… I don’t see how even 7x cheaper energy per area (current solar is ~200 W/m^2 avg, space maximum is 1360 W/m^2) can make up for those things. (edit: this accounts for weather + night + atmosphere effects, see below comment)
In addition to hitting higher energy from a given area, you also can get the same energy 100% of the time (without issues with night or clouds). But yeah, I agree, and I don’t see how you get 50x efficiency even if transport to space (and assembly/maintenance in space) were free.
I agree that even with free launch and no maintenance costs, you still don’t get 50x. But it’s closer than it looks.
On Earth, to get reliable self-contained solar power we need batteries that cost a lot more than the solar panels. A steady 1 kW load needs on the order of 15 kW peak-rated solar panels plus around 50 kW-hr battery capacity. Even that doesn’t get 99% uptime, but enough for many purposes and it is probably adequate when connected to a continent-spanning grid with other power sources.
The same load in orbit would need about 1.5 kW peak rated panels and less than 1 kW-hr of battery capacity for uptime dependent only upon reliability of equipment. The equipment does need to be designed for space, but doesn’t need to be sturdy against wind, rain, and hailstones. It would have increased cooling costs, but transporting heat (e.g. via coolant loop) into a radiator edge-on to the Sun will be highly effective (on the order of 1000 W/m^2 for a radiator averaging 35 C).
This is what I was talking about, I should have been more clear. Year-average daily ground irradiance in the US seems to be about 4-5 kWh/m^2 (this includes night + weather + atmosphere effects, does not include panel efficiency) ~= 200 W/m^2. In space (assuming sun-synchronous or non-LEO, which are both more expensive than LEO) you get 1361 W/m^2. So about 7x. In the Sahara Desert it’s ~300 W/m^2 so ground-solar worst case is 4-5x.