Comment by pveierland
7 hours ago
As problems go, radiation and cooling seem to have relatively low dimensionality compared to the other problems. It seems to be mostly a question of optimizing within the dimensions of dissipation / structure / deployment / service / cost / weight. When all is said and done, the cooling solution will end up being a module that can deal with some power dissipation, cost X amount, weight Y amount, have structural interface Z. This seems like something a relatively low number of engineers can iterate on largely isolated from other concerns. SpaceX does have 5000+ of them.
Comparing this to scaling the production of compute where they try to work outside the bounds of ASML (~40k employees) and TSMC (~80k+ employees), and where there is a huge number of degrees of freedom in many, many layers of the stack that have complicated interactions.
With radiation and cooling, SpaceX also has plenty of experience with both already given that they've had to solve this on existing satellites. Overall, Terafab just seems like a far harder challenge, and where I'd be more wary on timelines.
Radiators are raised because it's a known constraint and we know that Stefan Boltzmann implies a lot of radiator mass to be launched even at 100% cooling efficiency and there are also theoretical limits to launch efficiency which Starship is rapidly approaching.
Nobody is saying orbital datacentres can't be cooled, they're saying people arguing launching the mass of the required radiators into space is a better, more cost-effective cooling solution than pumping local water because "space is cold" are talking nonsense. Potential solutions don't look like trying to get 5000 engineers to invent radiators which defy the laws of physics, they probably look like amortising the costs over multiple decades of operation and ideally assembling the radiator portion of the datacentre from mass that's already in orbit, but that's not a near term profit pitch....
I read the comment that I replied to as these challenges being a large prohibitor to this development, and I pointed out that these seem like challenges that can be dealt with mostly in isolation from other challenges and in particular not require a large number of engineers to deal with.
Of course the major exercise becomes about total cost efficiency, but I think a large attraction is that once you've solved space deployment sufficiently, you don't need to keep dealing with local circumstances and power production adaptations to every new site you're dealing with on Earth, as it's more about producing a set of modules you can keep launching without individual adaptation - not about "space being cold".
The point is that they're absolutely not in isolation from other challenges because designing something to radiate heat at maximum possible radiative cooling efficiency is not considered to be a problem, solving the unit economics of launching the required radiator tonnage and burning 100 tonnes of rocket fuel to per tonne launched that's the problem. Cutting edge stuff like in-space refuelling and modular in-space reassembly and patient capital are crucial to making those work because the radiators aren't getting beyond 100% radiative cooling efficiency however well designed they are.
Optimizing for local circumstances is a benefit to doing things on earth: if having a production line and the ability to plug into wherever energy happens to be cheapest was better we'd all be sticking inference chips in shipping containers and not worrying about HVACs being relatively inefficient at cooling.
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I don't think anyone is saying that it's impossible to build a datacenter in space. Of course you can do that if you really want to.
But to make sense, it needs to be cheaper than on earth, and that seems unrealistic.
Space is cold. Space is also an excellent thermal insulator - there's a reason why Thermos bottles use vacuum for insulation...
Isn't the question more an economic one: Is it cheaper to put some solar cells into the desert and to buy some batteries, or to launch things into space (plus the premium for radiation hardening and ensuring it survives long enough because you cannot service it).
Given the current trajectory of battery and solar prices I just don't that space-based systems are cheaper in any way.
Of course there is a long-term aspect should we climb the ladder in the Kardashev scale: Once we used all solar radiation reaching earth we must move to space to grow. But that is decades if not centuries away.
you are ignoring the scale factor, approvals for this much infrastructure is really hard and slow