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zactato • today at 4:27 PM • 10 replies • view on HN

How are they solving the heat dissipation issues?


Replies

lopsotronic • today at 4:56 PM

For real. It's an enormous problem solved only with 1) sheer scale, and 2) Science Fiction.

Both of those are expensive as hell, by the way.

Cooling via radiation follows Stefan–Boltzmann: P = εσAT⁴. Let's assume a good surface (emissivity ~0.9) at 300 K (27 °C) at 400 W per square meter per side. A flat panel radiating from both faces into deep space gets 800 W/m, not including the losses from, say, the Sun, or from IR coming off the Earth. Now, input power. Sunlight in orbit ~1,360 W/m², assume ~22% cell efficiency, we got 300 W/m². So each 1 MW compute, 3,300 m² of solar panel and minimum 1,200–1,500 m² of radiator.

In case ya didn't know - 1 MW is tiny from a present-day-datacenter perspective. It's like 8 racks. So we're talking orbital megastructures here, many many many square kilometers, and this is with all the best case assumptions, and magic radiator panels that never see the sun, or the earth, or the moon.

This is just the basic numbers here, by the way. There's a garbage truck full of other unsolvable problems if you poke your head in there.

Aside from the "Avoid Regulations" aspect, and the "Everything That Burns Deorbiting is Depreciation" aka "The Starlink Trick", I'm not sure what the hell the draw is.

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Ifkaluva • today at 6:19 PM

From the article itself, sounds like it’s an open problem that they are experimenting with:

“ We’re working on a number of different approaches for this, including a combination of heat pipes and radiators to cool the chips. So far, our team has tested the technology in a thermal vacuum chamber that simulates both the thermal and vacuum environment in space. We’ll see how our new TPU cooling system works in space and refine our designs as we learn more.”

tills13 • today at 9:59 PM

Don't worry, they'll just ask Grok.

725686 • today at 9:02 PM

Can't they harness the heat to generate more electricity?

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xnx • today at 4:43 PM

No solution, but that is the crux of the problem. They probably need to make a radiator that 1000x smaller and lighter.

TPU: 100,000+ watts/square-meter

Radiator: ~300 watts/square-meter

https://youtu.be/ktdbUIZKeSE?t=76

kccqzy • today at 6:18 PM

The article mentions that:

> The biggest challenge was how to cool the A.I. chips, which heat up when they perform calculations and process information. Fans, which typically help dissipate the heat, do not work in space. So the Silicon Valley company instead developed a cooling system that uses layers of conductive material to expel the heat into space.

> The bottom layer is made up of Google’s A.I. chips, which sit on a green motherboard. The next layer consists of “thermal interface material,” a pale green putty that comes in sheets like Fruit Roll-Ups and connects the chips to layers of aluminum and copper, radiating heat away from the motherboard. Finally, there is a radiator panel, which projects heat into space.

> The chips can operate for about 15 minutes in space before needing to be shut down so they can cool off, said Travis Beals, Google’s senior director of product management for Project Suncatcher.

gmerc • today at 6:00 PM

We don't. This is all cover for the militarisation of space, there's no real benefit that'd be ever economical to put a DC up in space when you could build one on the ground. The whole narrative exists to allow google to tap into the Golden Dome / Space force bucket of pork that's basically SDI II.

You don't need civilian scale compute in space, but you absolutely can put miliary application up there and get filthy rich, like Elon, who doesn't care if it ever works, because he's getting paid as taxi service to shoot stuff up.

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JackSlateur • today at 4:47 PM

That's the neat part: you don't (ergo, this is yet another marketing crap)

ElijahLynn • today at 6:13 PM

I watched a video with Elon musk the other day and he was very confident saying it's already a solved problem and they already do it with Starlink to some degree. He was baffled that this debate keeps coming up.

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GMoromisato • today at 5:21 PM

Please stop with this argument. This is one of the easiest problems to solve. Heat dissipation requires a radiator, which is just a dumb hunk of metal. All you need is a cheap way to launch mass to orbit, which is exactly what SpaceX (and Chinese companies) are doing.

The only valid argument against data centers in space is the economic cost. If the per megatoken price for space datacenters is higher than terrestrial, then this won't work.

But the price for terrestrial datacenters keeps going up and technology keeps dropping the price of space-based.

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