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Data centers in space makes no sense

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Re: Data centers in space makes no sense

#161
post #31

I'm convinced that >30% of this comes from ideas leaking out of fiction such as like Neuromancer , and percolating through the minds of wealthy people attracted to some of the concepts. Namely, the dream of being a hyper-wealthy dynasty, above any earthly government, controlling an extraterritorial Las Vegas Fiefdom In Space. (Which in the book, also hosted a powerful AI.) Then they work backwards, trying to figure o…

well, don't forget, freeside's initial moneymaker was a datahaven for less-reputable banks!

Re: Data centers in space makes no sense

#162
post #115

I would not assume cooling has been worked out. 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…

Not disagreeing with you at all: that physics fact always come up. My honest question is: if it's a perfect thermos, what does, for example, the ISS do with the heat generated by computers and humans burning calories? The ISS is equipped with a mechanism to radiate excess heat into space? Or is the ISS slowly heating up but it's not a problem?

Re: Data centers in space makes no sense

#163
As a thought experiment, if humanity wanted to go all in on trying to move industrial processes and data centers off planet, would it make more sense to do so on the moon?

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.

Re: Data centers in space makes no sense

#164
post #2

AI data-centers use upwards of 100MW. The biggest solar panels in space could produce around 240KW. When they speak of AI data-centers in space what do they actually mean in realistic non theoretical terms and where are the materials for this coming from? 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 re…

This is the thing I don’t get. Everyone talking about the “how” but nobody talking about the “why”? It makes literally no sense.

Re: Data centers in space makes no sense

#165
post #112

Earlier quoted context omitted.

Well this explains why, but does not answer how to get rid of excessive heat in space.

What kind of the problem you're talking about compared to existing satellites? That is, all existing satellites generate power, and need to dissipate that power, and most of it goes to waste heat, and the satellites somehow do that successfully - what is the specific problem you're talking about, which can't be solved by the same means?

I mean you have this around the wrong way.

The reason we dont have a lot of compute in space, is because of the heat issue. We could have greater routing density on communication satellites, if we could dissipate more heat. If Starlink had solved this issue they would have like triple the capacity and could just drop everything back to the US (like their fans think they do) rather than trying to minimise the number of satellites traffic passes through before exiting back to a ground station usually in the same country as the source. In fact, conspiratorially, I think thats the problem he wants to solve. Because wet dreams of an unhindered, unregulated, space internet are completely unanswered in the engineering of Starlink.

I have actually argued this from the other side, and I reckon space data centres are sort of feasible in a thought experimental sense. I think its a solvable problem eventually. But heat is the major limiting factor and back of the napkin math stinks tbh.

IIRC the size/weight of the satellite is going to get geometrically larger as you increase the compute size due to the size of the required cooling system. Then we get into a big argument about how you bring the heat from the component to the cooling system. I think oil, but its heavy again, and several space engineering types want to slap me in the face for suggesting it. Some rube goldberg copper heatpipe network through atmosphere system seems to be preferred.

I feel like, best case, its a Tesla situation, he clears the legislative roadblocks and solves some critical engineering problem by throwing money at it, and then other, better people step in to actually do it. Also triple the time he says it will take to solve the problem.

And then, ultimately, as parts fail theres diminishing returns on the satellite. And you dont even get to take the old hardware to the secondary market, it gets dropped in the ocean or burnt up on reentry.

Re: Data centers in space makes no sense

#166
There are two very distinct kinds of AI workloads that go into data centres:

    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.

Re: Data centers in space makes no sense

#167
post #130

Earlier quoted context omitted.

Its very simple, xAI needs money to win the AI race, so best option is to attach to Elon’s moneybank (spacex) to get cash without dilution

That may be the plan, but this is also a great way for GDPR's maximum fine, based on global revenue, to bite on SpaceX's much higher revenue. And without any real room for argument.

[deleted]

Re: Data centers in space makes no sense

#168
post #115

I would not assume cooling has been worked out. 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…

The equation has a ^4 to the temperature. If you raise the temperature of your radiator by ~50 degrees you double its emission capacity. This is well within the range of specialised phase change compressors, aka fancy air conditioning pumps. Next up in the equation is surface emissivity which we’ve got a lot of experience in the automotive sector. And finally surface area, once again, getting quite good here with nan…

> Next up in the equation is surface emissivity which we’ve got a lot of experience in the automotive sector.

My car doesn't spend too much time driving in vacuum, does yours?

Re: Data centers in space makes no sense

#170
post #163

As a thought experiment, if humanity wanted to go all in on trying to move industrial processes and data centers off planet, would it make more sense to do so on the moon? 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 enou…

What if instead we moved it all to a closer rock that has even more water, even more materials to manufacture crude (and even advanced) things, even more surface, more protection from radiation, and even crazier still had significantly less launch costs?

Almost any reason why the moon is better than in orbit is a point for putting it on earth.

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