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Cooling in Space

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Re: Cooling in Space

#41

Post by Gh0stRAT »

pavlov wrote: post #23
tristanj wrote: post #11

Earlier quoted context omitted.

SemiAnalysis' report on orbital data centers estimated 4x terrestrial costs in 2026, then parity around ~2040. https://newsletter.semianalysis.com/p/to-boldly-go-the-case-...

Based on very specific assumptions: “…the world in which AI demand is so overwhelming as to exceed the already formidable datacenter capacity additions” — but also this same world is one where GPU chip supply is abundant, there just isn’t enough data centers to put them in. This does not seem like the likeliest scenario to me.

Agreed, how could we not have datacenter capacity for the GPUs when Meta has shown that you can go from a bare field to an operational datacenter in about 3 months by using tents instead of buildings?

Re: Cooling in Space

#42

Post by gnfargbl »

JoelJacobson wrote: post #28
kryptiskt wrote: post #10

Allow me to propose a modest alternative to space data centers, namely mountaintop data centers. This would consist of a container full of servers and GPUs and what else goes into a data center, a wind turbine for power and a communication module (say laser or microwave) for communicating with a base station with a fiber connection. This would be lifted on top of a mountain by a helicopter and bolted in place. Coolin…

I think we can't rule out the explanation that all the ideas of space data centers could be connected to a desire by some of finding additional applications for rockets that can transport stuff to space.

I think we can't rule out the explanation that all the ideas of space data centers could have been connected solely to a desire to pump SpaceX's IPO.

Re: Cooling in Space

#43

Post by jdw64 »

_puk wrote: post #37
jdw64 wrote: post #22

Earlier quoted context omitted.

If that's the case, wouldn't it be better to just put it in the desert? Realistically, if noise from calculations is the problem, placing it in a remote area would be more economical.

It's a play on "in space no-one can hear you scream", not a literal "compute is so noisy we need to go to space" The jurisdiction issue is the bigger one. Deserts don't solve this; International waters, possibly do, but then you've got other issues.

Is that so? How embarrassing. I'm not a native English speaker, so I didn't understand the metaphor.

Re: Cooling in Space

#44

Post by zarzavat »

noisy_boy wrote: post #26
kryptiskt wrote: post #10

Allow me to propose a modest alternative to space data centers, namely mountaintop data centers. This would consist of a container full of servers and GPUs and what else goes into a data center, a wind turbine for power and a communication module (say laser or microwave) for communicating with a base station with a fiber connection. This would be lifted on top of a mountain by a helicopter and bolted in place. Coolin…

What about the rough weather and difficulty of maintenance, especially in rough weather?

Maintenance for a mountaintop data center only requires a team of skilled mountaineers. In space you'd need astronauts. It's at least an order of magnitude cheaper, perhaps two or three.

Re: Cooling in Space

#45

Post by andriesm »

If I had a dollar for everytime someone told me they have an advanced physics degree and can unequivocally gaurantee me that it will never be physically feasible to cool GPU's in space.... How soon those people have disappeared!

Re: Cooling in Space

#46

Post by mkl »

BadBadJellyBean wrote: post #18
jdw64 wrote: post #17

What I don't understand about building a space data center is that you need radiators to release heat. Otherwise, it will become a space thermos. What's even more incomprehensible is that you would need specialized equipment for space radiation, and GPUs are consumables. To make that profitable, you would need pricing that is many times higher than the cost of a regular data center. I don't understand why there are p…

I have the feeling that the only reason that might actually be done is to escape from any kind of jurisdiction. In space no one can hear you compute.

The Outer Space Treaty [1] says "A State Party to the Treaty on whose registry an object launched into outer space is carried shall retain jurisdiction and control over such object", so no escaping jurisdiction.

[1] https://en.wikipedia.org/wiki/Outer_Space_Treaty, https://en.wikisource.org/wiki/Outer_Space_Treaty_of_1967#Ar...

Re: Cooling in Space

#47

Post by notahacker »

BadBadJellyBean wrote: post #18
jdw64 wrote: post #17

What I don't understand about building a space data center is that you need radiators to release heat. Otherwise, it will become a space thermos. What's even more incomprehensible is that you would need specialized equipment for space radiation, and GPUs are consumables. To make that profitable, you would need pricing that is many times higher than the cost of a regular data center. I don't understand why there are p…

I have the feeling that the only reason that might actually be done is to escape from any kind of jurisdiction. In space no one can hear you compute.

You don't get that with the current plans which require them to have FCC licences and be constantly replacing them by launching from the United States though...

Re: Cooling in Space

#48

Post by regularfry »

Don't we also have to worry about heating of the solar panels themselves? 150W/m^2 isn't the incident power, it's the output power. Incident is something like ten times that. Some of that's going to be reflected, but not all of it.

Re: Cooling in Space

#49

Post by adrian_b »

XorNot wrote: post #14
echoangle wrote: post #6

I still don’t see what the advantage is. Of course it’s physically possible to build a datacenter in space, but I can’t imagine land prices being that high that the same data center on earth wouldn’t be cheaper. Even just due to launch costs and the more sophisticated equipment needed for space.

The real issue is that the power situation in LEO is still actually terrible! Your solar is a little more performant, but you're plunged into hard shade every 45 minutes.

There exist the so-called Sun-synchronous orbits, which exploit the precession effect caused by the fact that the Earth is not a sphere, to pass over the same point of the Earth at the same local hour. On a small subset of these Sun-synchronous orbits the Sun is always visible from the satellite (i.e. on the subset of orbits whose plane is approximately perpendicular on the radius that connects the Sun to the Earth). Without the precession effect, a satellite that sees the Sun for an entire day would lose this property after a few days, because of the rotation of the Earth around the Sun, which alters the direction in space of the radius from the Sun to the Earth.

However, the number of slots that are available in Sun-synchronous orbits with permanent view of the Sun is limited, and many potential users want them. So those who desire to build datacenters would have to compete for such orbital slots. There are much less such slots than for geosynchronous orbits. Other countries would certainly be outraged if USA occupied all the available slots with datacenters.

Improved control of the satellites for collision avoidance could allow smaller slots, but maneuvering heavy datacenters would require a lot of fuel, so they might require periodic refueling, greatly increasing the costs.

Re: Cooling in Space

#50

Post by vessenes »

mcapodici wrote: post #19

Seems reasonable that the area needed would be less than the solar panels. Since it sould be more efficient to dump heat than collect energy from light.

It seems to me that there’s a lot of math in the middle of this that just doesn’t matter that much: every photon hitting every part of the array is going to add energy. Whatever percent we transform into data doesn’t matter — all the energy from all those photons minus energy used for station keeping needs to be radiated away. I guess if some is used for station keeping so much the better.

I was hoping to read about what exactly these ‘heat pump radiators’ look like, but I guess ultimately they’re going to be lasers or flashlights or some such thing.

A relativity course question I recall from my youth asked how long an astronaut stranded 1km from a ship would need to point the flashlight away to return to the ship based on the mass of the photons leaving the light — spoiler - this can work in time to save an astronaut’s life — double spoiler: if you’re really accurate, it’s better to throw the flashlight if you’re in a hurry.

As I write this I realize my physics model is super weak, because I’m not sure what percent of the energy used to make a photon turns into the photon’s mass (and therefore is pushing against the laser), and what is in light and therefore just, you know, carries on for billions of years until it hits something else.

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