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Data centers in space makes no sense

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Re: Data centers in space makes no sense

#551
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…

It has been worked out. Just look at how big are ISS radiators and that they dissipate around 100kW then calculate cost of sending all that to space. And by that I mean it would be even more expensive that some of the estimates flying around

While personally I think it's another AI cash grab and he just wants to find some more customers for spacex, other thing is "you can't copyright infringe in space" so it might be perfect place to load that terabytes of stolen copyrighted material to train data sets, if some country suddenly decides corporation stealing copyright content is not okay any more

Re: Data centers in space makes no sense

#552
post #48
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…

I assume the idea is to have the entire constellation be the data center in question. Laser back haul transceiver bandwidth is in the same order of magnitude of rack-to-rack bandwidths [1][2]. I could see each sat being a rack and the entire mesh being a cluster. [1] https://hackaday.com/2024/02/05/starlinks-inter-satellite-la... (and this is two years ago!) [2] https://resources.nvidia.com/en-us-accelerated-networki…

For AI training, latency is one of the limiting factors, which needs to be kept in the nanoseconds. And a light-nanosecond is famously almost exactly 1 foot.

That's why Lumen/Starcloud's designs all assume it'll be a space station with all containers connected to one central networking spine.

Re: Data centers in space makes no sense

#553

The really crazy thing is you don't need to know more then basic (non Hollywood) physics to know how dump this is 1. every gram you need to send to space is costly, a issue you don't have at ground level 2. cooling is a catastrophe, sure space is cold, but also a vacuum, so the cooling rate is roughly the infrared radiation rate. This means if you are not careful with the surface of a satellite it can end up being ve…

I don't know if data centers in space make sense or not, but I'm really not liking these comments that say something is "too expensive" or "too hard" without actually crunching the numbers to verify if it actually is. It's like you point out a number of completely obvious problems with the scheme and immediately, without any detailed analysis or expertise (I know this, because surely you can't have expertise in all of the problems you cited) in the said problems, claim that they are completely impossible for anyone to ever solve.

> 1. every gram you need to send to space is costly, a issue you don't have at ground level

This is a one time cost. Maybe the running costs are cheap enough to offset this.

> 2. cooling is a catastrophe, sure space is cold, but also a vacuum, so the cooling rate is roughly the infrared radiation rate. This means if you are not careful with the surface of a satellite it can end up being very slowly cooked by sunlight alone not including running any higher heat producing component (as it absorbs more heat from sunlight then it emits, there is a reason satellites are mostly white, silver or reflective gold in color). Sure better surface materials fix that, but not to a point where you would want to run any heavy compute on it.

I would assume the people designing this are "very careful" with everything they put in the data center. If achieving the cooling is only very hard and requires careful material engineering, then it can be worked out and they will get it done. If it is impossible, then this will not happen, but I'm a physicist myself and I can't tell without a very involved analysis whether it is impossible or not to get enough cooling power for this in space, considering all, possibly ingenious ways to engineer the surfaces of the data center to dissipate a maximum amount of heat.

> 3. zero repair-ability, most long running satellites have a lot of redundancy. Also at least if you are bulk buying Nvidea GPGPUs on single digit Million Euro basis it's not rare that 30% have some level of defect. Not necessary "fully broken" but "performs less good then it should/compared to other units" kind of broken.

I suppose they could make something like the International Space Station, which would get regular traffic back-and-forth exchanging and servicing hardware as needed.

> 4. radiation/solar wind protections are a huge problem. Heck even if you run things on earth it's a problem as long as your operations scale is large enough. In space things are magnitudes worse.

Again, it's not a question whether this is "problematic"; everything about putting data centers in space is. The question is whether, with huge amount of work and resources, they can engineer a solution to overcome this. If they can, it's again a one time cost for the data center that might be offset by the running costs of the facility.

> 5. every rocket lunch causes atmospheric damage, so does every satellite evaporating on re-entry. That wasn't that relevant in the past, but might become a problem just for keeping stuff like Starlink running. We don't need to make it worse by putting datacenters into space.

> 6. Kessler Syndrom is real and could seriously hurt humanity as a whole, no reason to make it much more likely by putting things into space which don't need to go there.

These are collective problems for the whole of humanity and will not concern an individual actor such as Elon Musk who wants to send more satellites into space.

Re: Data centers in space makes no sense

#554
post #531

Earlier quoted context omitted.

What in particular is wrong/misleading in the Starcloud whitepaper, then? https://starcloudinc.github.io/wp.pdf

In Table 1, the cost of cooling of a terrestrial data centre is listed as $7M. The cost of cooling in space is assigned a value of $0 with the claim: "More efficient cooling architecture taking advantage of higher ΔT in space" My bold claim: The cost of cooling will not be $0. The cost of launching that cooling into space will also not be $0. The cost of maintaining that mechanically complex cooling in space will not…

That row specifically says "chiller energy cost" which is 0

Re: Data centers in space makes no sense

#555
post #546
post #379

Data centers in space may or may not make sense (personally I'm quite skeptical) but the objections in the article certainly don't make sense. 1. The only reason there are 15,000 satellites in space is because SpaceX launched about 9,500 of them (Starlink is 65% of all satellites) on their semi-reusable Falcon 9. If fully-reusable Starship pans out, they will be launching satellites at 10x the rate of Falcon 9 at the…

A few additional items to rebut the lack of info in this Article: - SpaceX just requested a license to launch up to a million satellites. - the satellites already have some incredible anti collision software, which I believe Elon has now open sourced. - the cost to launch 1 kg to space has dropped by a factor of 10 in the past few years and is currently less than $1000. It's perfectly reasonable to estimate that over…

Elon has open sourced them, or the people at SpaceX who actually know or understand something did?

Re: Data centers in space makes no sense

#556

Earlier quoted context omitted.

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…

What about sourcing and the cost of energy? Solar Panels more efficient, no bad weather, and 100% in sunlight (depending on orbit) in space. Not that it makes up for the items you listed, but it may not be true that everything is more difficult in space.

just take cost of getting kg in space and compare it to how much solar panel will generate

Current satellites get around 150W/kg from solar panels. Cost of launching 1kg to space is ~$2000. So we're at $13.3(3)/Watt. We need to double it because same amount need to be dissipated so let's round it to $27

One NVidia GB200 rack is ~120kW. To just power it, you need to send $3 240 000 worth of payload into space. Then you need to send additional $3 106 000 (rack of them is 1553kg) worth of servers. Plus some extra for piping

Re: Data centers in space makes no sense

#557

Earlier quoted context omitted.

Resistive heating is a tremendously inefficient way to generate heat. Sometimes it's worth it if you get something useful in exchange (such as full spectrum light in the winter). But it's not all upsides. Heat pumps are magic . They're something like 300% efficient. Each watt generates 3 watts of useful heat.

I share your enthusiasm about heat pumps, but I wonder what the efficiency of using waste heat is. Couldn't it be competitive with heat pumps? As it's a waste product, isn't it reasonable to also expect it to be more than 100% efficient?

Much more than 100% since the only energy you need to put in is for pumping the hot water around.

Re: Data centers in space makes no sense

#558

Earlier quoted context omitted.

The story here is even simpler. SpaceX is going public this year. Elon made a monumentally shitty investment in Twitter and then poured a stupid amount of money into xAI at the peak of the cycle. By having SpaceX buy xAI, he gets to swap worthless shares in that company for more SpaceX liquidity. Simple as that.

Really seems silly to think that the guy with $800 billion is spending most of his time maximizing his money.

Welcome to billionares. If they weren't obsessed with "number go up" over any other consideration, they wouldn't be billionares.

Re: Data centers in space makes no sense

#559
post #310
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…

Simply put no, 50MW is not the typical hyperscaler cloud size. It's not even the typical single datacenter size. A single AI rack consumes 60kW, and there is apparently a single DC that alone consumes 650MW. When Microsoft puts in a DC, the machines are done in units of a "stamp", ie a couple racks together. These aren't scaled by dollar or sqft, but by the MW. And on top of that... That's a bunch of satellites not e…

For another reference, the Nvidia-OpenAI deal is reportedly 10GW worth of DC.

Re: Data centers in space makes no sense

#560
Let's do some napkin math on it

Current satellites get around 150W/kg from solar panels. Cost of launching 1kg to space is ~$2000, so we're at $13.3(3)/Watt, that just power, let's assume that cooling will cost us same per kg, the same amount need to be dissipated so let's round it to $27

One NVidia GB200 rack is ~120kW. To just power it, you need to send $3 240 000 worth of payload into space. Then you need to send additional $3 106 000 (rack of them is 1553kg) worth of servers. Plus some extra for piping. We're already at $6.3 mil a pop for just hauling it up to orbit, with no cost of solar cells included

I'd imagine comparable hardware for just some solar + batteries on ground is around $200k. I dunno where the repeated 5x cost number comes from. I suspect whoever pushed it was just lying

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