That's not a new problem that no one has dealt with before. The ISS for instance has its External Active Thermal Control System (EACTS).

It's not so much a matter of whether it's an unsolvable problem but more like, how expensive is it to solve this problem, what are its limitations, and does the project still makes economic sense once you factor all that in?

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OneDeuxTriSeiGo 3 hours ago | parent | next [-]

It's worth noting that the EACTS can at maximum dissipate 70kW of waste heat. And EEACTS (the original heat exchange system) can only dissipate another 14kW.

That is together less than a single AI inference rack.

And to achieve that the EACTS needs 6 radiator ORUs each spanning 23 meters by 11 meters and with a mass of 1100 kg. So that's 1500 square meters and 6 and a half metric tons before you factor in any of the actual refrigerant, pumps, support beams, valve assemblies, rotary joints, or cold side heat exchangers all of which will probably together double the mass you need to put in orbit.

There is no situation where that makes sense.

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Manufacturing in space makes sense (all kinds of techniques are theoretically easier in zero G and hard vacuum).

Mining asteroids, etc makes sense.

Datacenters in space for people on earth? That's just stupid.

	▲	marcus_holmes 5 minutes ago \| parent [-]
		I'm a total noob on this. I get that vacuum is a really good insulator, which is why we use it to insulate our drinks bottles. So disposing of the heat is a problem. Can't we use it, though? Like, I dunno, to take a really stupid example: boil water and run a turbine with the waste heat? Convert some of it back to electricity?

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hyperbovine 3 hours ago | parent | prev [-]

The ISS consumes roughly 90kW. That’s about *one* modern AI/ML server rack. To do that they need 1000 m^2 of radiator panels (EACTS). So that’s the math: every rack needs another square kilometer of stuff put into orbit. Doesn’t make sense to me.

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dnqthao 27 minutes ago | parent | next [-]

1000m2 is not a square kilometer (1 square kilometer is 1mil m2)

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jcgrillo 3 hours ago | parent | prev [-]

And what happens every time a rack (or node) fails? Does someone go out and try to fix it? Do we just "deorbit" it? How many tons per second of crap would we be burning in the upper atmosphere now? What are the consequences of that?

How do the racks (or nodes) talk to eachother? Radios? Lasers?

What about the Kessler Syndrome?

Not a rocket scientist but 100% agree this sounds like a dead end.

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elihu 2 hours ago | parent [-]

Communication is a well-understood problem, and SpaceX already has Starlink. They might need pretty high bandwidth, but that's not necessarily much of a problem in space. Latency could be a problem, except that AI training isn't the sort of problem where you care about latency.

I'd be curious where exactly they plan to put these datacenters... In low Earth orbit they would eventually reenter, which makes them a pollution source and you'd have no solar power half the time.

Parking them at the Earth-Sun L1 point would be better for solar power, but it would be more expensive to get stuff there.

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WalterBright an hour ago | parent [-]

> you'd have no solar power half the time

Polar orbit.

	▲	woooooo an hour ago \| parent [-]
		Seasons mess that up unless you're burning fuel to make minor plane changes every day. Otherwise you have an equinox where your plane faces the sun (equivalent to an equatorial orbit) and a solstice where your plane is parallel to the sun (the ideal case).