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Data centers in space makes no sense

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Re: Data centers in space makes no sense

#751

Post by OscarCunningham »

drowsspa wrote: post #150
general1465 wrote: post #67

Earlier quoted context omitted.

Well the issue is that a lot of people believe that space is cold. If you will ask Google/Gemini what is a temperature of space, it will tell you: The average temperature of deep space is approximately -270.45°C or 2.73 Kelvin), which is just above absolute zero. This baseline temperature is set by the Cosmic Microwave Background (CMB) radiatio... Which is absolute nonsense, because vacuum has no temperature.

That's not how it works. Two bodies are in thermal equilibrium if there's no heat transfer between them: that's the zeroth law of thermodynamics. If you're colder than 2.73K in deep space, you will absorb the heat from the Cosmic Microwave Background. If you're hotter, you will irradiate heat away. So it does have a temperature.

Does this mean that if Earth stays a fixed distance from the sun then its equilibrium temperature is fixed? I remember people saying things like that the albedo of the ice caps affected the Earth's temperature.

Re: Data centers in space makes no sense

#752

Post by t312227 »

hello,

as always: imho. (!)

we already had this topic before, an example for another good article regarding physical arguments against this idea would be:

"Datacenters in space are a terrible, horrible, no good idea" ~ late 2025

* https://taranis.ie/datacenters-in-space-are-a-terrible-horri...

TL;DR: It's not going to work.

idk ... maybe elon has something else in mind with this merger!?

cheers,

a..z

Re: Data centers in space makes no sense

#754

Post by qoez »

> Training and serving frontier AI at scale takes hundreds of thousands of GPUs. xAI’s Colossus cluster reportedly has 200,000 GPUs. OpenAI has plans for millions of them. Competing in this market would require launching hundreds of thousands, if not millions, of satellites into space

No? You'd only need one with lots of gpus on the ship at the same time

Re: Data centers in space makes no sense

#755

Post by Ajedi32 »

FranklinJabar wrote: post #609
mike_hearn wrote: post #582

Earlier quoted context omitted.

It sounds hard but it shouldn't not make sense. 1. Solving cost of launching mass has been the entire premise of SpaceX since day one and they have the track record. 2. Ingress/egress aren't at all bottlenecks for inferencing. The bytes you get before you max out a context window are trivial, especially after compression. If you're thinking about latency, chat latencies are already quite high and there's going to be…

> There is probably plenty of scope to optimize space radiators. It was never a priority until now and is "just" an engineering problem. Well, it's a physics problem. The engineering solution is possibly not cost efficient. I'd put a lot of money that it isn't.

What makes you so sure? SpaceX already has thousands of 6 kW networking racks flying around in LEO and they dissipate their heat just fine, and are plenty cost-effective. You think they can't do any better than that with a new design specifically optimized for computing rather than networking?

Re: Data centers in space makes no sense

#756

Post by tfehring »

monooso wrote: post #661
mike_hearn wrote: post #582

Earlier quoted context omitted.

It sounds hard but it shouldn't not make sense. 1. Solving cost of launching mass has been the entire premise of SpaceX since day one and they have the track record. 2. Ingress/egress aren't at all bottlenecks for inferencing. The bytes you get before you max out a context window are trivial, especially after compression. If you're thinking about latency, chat latencies are already quite high and there's going to be…

I have no expertise is this area, so I'm not getting into whether or not this idea makes sense. That being said, this statement strikes me as missing the point: > Solving cost of launching mass has been the entire premise of SpaceX since day one and they have the track record. As I understand it, SpaceX has a good track record of putting things into space more cost effectively than other organisations that put things…

I don’t think that statement was missing the point. As you point out, what matters is the total cost of ownership of the system. The cost of launching mass into space today isn’t the only reason terrestrial data centers are more cost effective today, but it’s the main one. If you make it cheap enough to send giant solar arrays and radiators to space, the other costs of operating in space may start to look like a small price to pay to eliminate the need for inputs like land and batteries.

Re: Data centers in space makes no sense

#757

Post by vonneumannstan »

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…

Yeah the Space Data Center companies completely gloss over this fact by saying "oh yeah and we'll need radiators 10x the size of our solar panels. NBD."

Re: Data centers in space makes no sense

#758

Post by Symmetry »

Numerlor wrote: post #674
killerstorm wrote: post #663

Earlier quoted context omitted.

People did the calculation: radiative cooling requires smaller surface area than solar panels. So, basically, a solar panel itself can radiate heat. Have you done a calculation yourself?

How can the solar panel itself radiate heat when it's being heated up generating supplying power? Looking at pictures of the ISS there's radiators that look like they're there specifically to cool the solar panels. And even if viable, why would you just not cool using air down on earth? Water is used for cooling because it increases effectiveness significantly, but even a closed loop system with simple dry air heat e…

You take the amount of energy absorbed by the solar panels and subtract the amount they radiate. Most things in physics are linear systems that work like this.

Re: Data centers in space makes no sense

#759

Post by pclmulqdq »

FabHK wrote: post #515
pclmulqdq wrote: post #453

Earlier quoted context omitted.

I think you may be overestimating how quickly this happens and underestimating how much surface area that rock has. Given no atmosphere, the fact that the rock with 1/4 the radius of Earth has a temperature differential of only 300C between the hot side and the cold side, there's not a lot of radiation happening. In deep space (no incident power) you need roughly 2000 sq meters of surface area per megawatt if you wan…

First, thanks for your knowledgeable input. Second, are you saying that we basically need to have a radiator as big (approximately) as the solar panels? That is a lot, but it does sound manageable, in the sense that it approximately doubles what we require anyway for power. So, not saying that it’s easy or feasible, but saying that cooling then seems “just” as difficult as power, not insurmountably more difficult. (N…

> So, not saying that it’s easy or feasible, but saying that cooling then seems “just” as difficult as power, not insurmountably more difficult

This is with an ideal radiator and perfect pointing so it receives no incident light, so in practice you need a bigger one than this.

However, if you think launching a solar panel that is the size of 10 NYC city blocks is "manageable," then why not throw in a radiator that is about 15 city blocks in size?

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