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Data centers in space makes no sense

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Re: Data centers in space makes no sense

#271

Post by gowld »

threecheese wrote: post #256
Terr_ wrote: 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…

Stole Grok from Heinlein. At least it’s a good heuristic for people-I-don’t-have-to-take-seriously.

More likely, stole grok from nerds who learned grok from Heinlein.

Re: Data centers in space makes no sense

#272

Post by sfink »

OrvalWintermute wrote: post #217

This is written by someone that is not in aerospace that thinks terrestrially. Engineering is always a question of tradeoffs. Launch costs are dropping, and we’re still using inefficient rockets. Space elevators & space trains, among others, can drop this much more, the launch costs are still dropping, even using rockets, maybe we’ll never get to elevators & trains the costs will drop so low! Radiation shielding is n…

> Cooling can be significantly improved due to lower launch costs, heat piping, RTGs, TEGs, and thermoradiative cells, not to mention sunside solar and darkside inline radiators

You're saying they're going to steal the night? We'll see the sun in the day, radiative cooling for surveillance AI in the time formerly known as night?

I'll confess that the numbers aren't nearly as bad as I'd thought. Apparently, you can dissipate 1MW at 100°C with a 17m diameter sphere at night. So it's like the size of a small house. It doesn't even glow. On the other hand, you need a lot of temperature differential to move the heat out fast enough, which means your TPUs are going to be hellishly hot.

Though you'd probably only run it when it's in the sun and radiate in other directions, so you don't have to store the power in heavy batteries. You need a 56m diameter disk of solar panels to provide 1MW, don't forget that.

(All figures were vibe calculated with Claude and are unchecked.)

Re: Data centers in space makes no sense

#273

Post by 3eb7988a1663 »

denkmoon wrote: post #160
bagels wrote: post #134

Earlier quoted context omitted.

You can reject the heat by shedding hot mass, but only once.

Cooling by mass effect style yeeting hot chunks of metal out the back. Where will they go, nobody knows!

Depending on where they land, you can double the service you offer. AI computations coupled with rods from God.

Re: Data centers in space makes no sense

#276

Post by thinkingkong »

pokot0 wrote: post #262
beloch wrote: 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…

Can’t you heat exchange inside the satellite, and make one part of the satellite incredibly hot so that it radiates a lot and dissipates. This is just a question. I have no expertise at all with this.

You definitely _can_ the question is, can you do it by enough for a reasonable amount of money. There are a few techniques to this but at the end of the day you need to radiate away, the heat otherwise it will just keep growing. You cannot keep pumping energy into the satellite without distributing the same amount back out again.

Re: Data centers in space makes no sense

#277

Post by pas »

pokot0 wrote: post #262
beloch wrote: 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…

Can’t you heat exchange inside the satellite, and make one part of the satellite incredibly hot so that it radiates a lot and dissipates. This is just a question. I have no expertise at all with this.

Yes, but you need energy to pump heat, and that has an efficiency maximum (thx ~~Obama~~ Carnot), and radiative cooling scales with the ~4th power of the temperature, so it has to be really hot, and so it requires a lot of energy to "cool down" the already relatively cool side and use that "heat" to heat up the other side that's a thousand degree hotter.

All in all, the cooling system would likely consume more energy than the compute parts.

Re: Data centers in space makes no sense

#278

Post by parl_match »

pokot0 wrote: post #262
beloch wrote: 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…

Can’t you heat exchange inside the satellite, and make one part of the satellite incredibly hot so that it radiates a lot and dissipates. This is just a question. I have no expertise at all with this.

yes. it is how sats currently handle this. its actually exponentially effective too P = E S A T^4

requires a lot of weight (cooling fluid). requires a lot of materials science (dont want to burn out radiator). requires a lot of moving parts (sun shutters if your orbit ever faces the sun - radiator is going to be both ways).

so that sounds all well and good (wow! 4th power efficiency!) but it's still insanely expensive and if your radiator solution fucks up in any way (in famously easy to service environment space) then your entire investment is toast

now i havent run the math on cost or what elon thinks the cost is, but my extremely favorable back of hand math suggests he's full of it

Re: Data centers in space makes no sense

#279

Post by murderfs »

space_fountain wrote: post #265
gpt5 wrote: post #235

Earlier quoted context omitted.

I'm confused about the level of conversation here. Can we actually run the math on heat dissipation and feasibility? A Starlink satellite uses about 5K Watts of solar power. It needs to dissipate around that amount (+ the sun power on it) just to operate. There are around 10K starlink satellites already in orbit, which means that the Starlink constellation is already effectively equivalent to a 50 Mega-watt (in a rou…

It's like this. Everything about operating a datacenter in space is more difficult than it is to operate one on earth. 1. The capital costs are higher, you have to expend tons of energy to put it into orbit 2. The maintenance costs are higher because the lifetime of satellites is pretty low 3. Refurbishment is next to impossible 4. Networking is harder, either you are ok with a relatively small datacenter or you have…

> The maintenance costs are higher because the lifetime of satellites is pretty low

Presumably they're planning on doing in-orbit propellant transfer to reboost the satellites so that they don't have to let their GPUs crash into the ocean...

Re: Data centers in space makes no sense

#280

Post by DaedalusII »

m463 wrote: post #65
wrs wrote: post #54

Next up, the Boring Company gets imaginary contract for underground datacenters, is now valued at $500B.

there was an article recently about a company wanting to put nuclear reactors at the bottom of very deep boreholes (like km deep). I thought that was actually quite interesting/practical, because if there is a problem, you can just bury the problem. not like tmi/fukushima/chernobyl

Interesting idea. 2km deep could work. I'm not sure how cooling or maintenance would work.

Depth below surface | Typical temperature (°C) | Indicative cost to drill 1.2 m diameter hole

500 m | 15–25 | $5–10 million

1 km | 25–40 | $10–20 million

2 km | 50–70 | $25–45 million

3 km | 75–100 | $50–80 million

4 km | 100–130 | $90–140 million

5 km | 130–160 | $150–250 million

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