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Datacenters in space aren't going to work

taranis.ie

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Re: Datacenters in space aren't going to work

#171

Post by santoshalper »

GMoromisato wrote: post #161

There are 8,000+ Starlink satellites in orbit right now. Each one has about 30 square-meters of solar panels. That's 240,000 square meters. ISS has 25,000 square meters, so SpaceX has already launched almost 10-times the solar panels of ISS. The next generation Starlink (V3) will have 250 square meters of solar panels per satellite, and they are planning on launching about 10,000 of them, so now you're at 2.5 million…

The facts you quoted just made me even more convinced that space-based datacenters will not be cost effective any time soon. If an entire generation of satellites costing many billions of dollars can't power more GPUs than a single terrestrial datacenter, how could it possibly be cost effective?

Re: Datacenters in space aren't going to work

#172

Post by shagie »

I'd be most curious to see what type of processing power they would put on such a data center.

For example, the JWST uses a RAD750 ( https://en.wikipedia.org/wiki/RAD750 ) which is based on a PowerPC 750 running at 110 MHz to 200 MHz.

Its successor is the RAD5500 ( https://en.wikipedia.org/wiki/RAD5500 )... which runs at between 66 MHz and 462 MHz.

> The RAD5545 processor employs four RAD5500 cores, achieving performance characteristics of up to 5.6 giga-operations per second (GOPS) and over 3.7 GFLOPS. Power consumption is 20 watts with all peripherals operating.

That's kind of neat... but not exactly data center performance.

Back to the older RAD750...

> The RAD750 system has a price that is comparable to the RAD6000, the latter of which as of 2002 was listed at US$200,000 (equivalent to $349,639 in 2024).

That isn't exactly price performance. Well, unless you're constrained by "it costs millions to replace it."

So... I'm not really sure what devices they'd be putting up there.

The "data centers in space" is much more a "space launch is a hot technology, AI and data centers are a hot technology... put the two together and its too the moon!" (Or at least that's what we tell the investors before we try to spend all their money)

Re: Datacenters in space aren't going to work

#173

Post by mandevil »

suriya-ganesh wrote: post #137
MadnessASAP wrote: post #133

Earlier quoted context omitted.

If they're already well versed in dodging fiscal rules, why do they need a space computer?

Physical location is difficult to dodge unfortunately. Fiscal rules are sort of man made.

The Outer Space Treaty is very very clear: anything launched into space is the responsibility of the country that launched it. Even if a private company payts for it and operates it, it's still the responsibility of the launching nation. Even if you launch from international waters, your operating company is still registered to a specific country, and the company is made up of citizens of one or more countries, and it is those countries which are responsible for the satellites. Those countries, in fact, have the responsibility to make sure that their citizens follow their laws and regulations. Unless you and your entire team are self-sustaining on that datacenter in outer space (maybe possible a century from now? Maybe not possible ever), you will be hunted down by the proper authorities and held to account for your actions. There is no magic "space is beyond the law" rules; it is just as illegal- and you are just as vulnerable to being arrested- for work done on a datacenter in space as work done on a datacenter on the ground.

Re: Datacenters in space aren't going to work

#174

Post by andrewflnr »

foobarian wrote: post #163
andrewflnr wrote: post #103

Earlier quoted context omitted.

This question is thoroughly covered in the linked article.

Pardon, but the question of "could the operational cost be smaller in space" is almost not touched at all in the article. The article mostly argues that designing thermal management systems for space applications is hard, and that the radiators required would be big, which speaks to the upfront investment cost, not ongoing opex.

Ok, sure, technically. To be fair you can't really assess the opex of technology that doesn't exist yet, but I find it hard to believe that operating brand new, huge machines that have to move fluid around (and not nice fluids either) will ever be less than it is on the surface. Better hope you never get a coolant leak. Heck, it might even be that opex=0 still isn't enough to offset the "capex". Space is already hard when you're not trying to launch record-breaking structures.

Even optimistically, capex goes up by a lot to reduce opex, which means you need a really really long breakeven time, which means a long time where nothing breaks. How many months of reduced electricity costs is wiped out if you have to send a tech to orbit?

Oh, and don't forget the radiation slowly destroying all your transistors. Does that count as opex? Can you break even before your customers start complaining about corruption?

Re: Datacenters in space aren't going to work

#175

Post by wat10000 »

foobarian wrote: post #160
tstrimple wrote: post #155

Earlier quoted context omitted.

I think you’re ignoring a huge factor in how radiative cooling actually works. I thought the initial question was fine if you hadn’t read the article but understand the downvotes due to doubling down. Think of it this way. Why do thermoses have a vacuum sealed chamber between two walls in order to insulate the contents of the bottle? Because a vacuum is a fucking terrible heat convector. Putting your data center into…

Pardon but this doesn't make sense to me. A 1 m^2 radiator in space can eliminate almost a kilowatt of heat. >vacuum is a fucking terrible heat convector Yes we're talking about radiating not convection

At what temperature?

And a kilowatt from one square meter is awful. You can do far more than that with access to an atmosphere, never mind water.

Re: Datacenters in space aren't going to work

#176

Post by Hikikomori »

foobarian wrote: post #146
noselasd wrote: post #106

Earlier quoted context omitted.

Is it an advantage though ? One of the main objections in the article is exactly that. There's no atmosphere that helps with heat loss through convection, there's nowhere to shed heat through conduction, all you have is radiation. It is a serious engineering challenge for spacecrafts to getting rid of the little heat they generate, and avoid being overheated by the sun.

I think it is an advantage, the question is just how big, and assume we look only at ongoing operation cost. - Earth temperatures are variable, and radiation only works at night - The required radiator area is much smaller for the space installation - The engineering is simple: CPU -> cooler -> liquid -> pipe -> radiator. We're assuming no constraint on capex so we can omit heat pumps

Radiators on earth mainly do it to air, there's no air in space.

Re: Datacenters in space aren't going to work

#177

Post by Hikikomori »

foobarian wrote: post #153
skywhopper wrote: post #95

Earlier quoted context omitted.

But the cooling cost wouldn’t be smaller. There’s no good way to eliminate the waste heat into space. It’s actually far far harder to radiate the waste heat into space directly than it would be to get rid of it on Earth.

I don't know about that. Look at where the power goes in a typical data center, for a 10MW DC you might spend 2MW just to blow air around. A radiating cooler in space would almost eliminate that. The problem is the initial investment is probably impractical.

Now scale the radiator size for your 8MW datacenter.

Re: Datacenters in space aren't going to work

#178

Post by wat10000 »

mbesto wrote: post #120

Datacenters in space is about circumventing nation states masked as ambitions to generate more power. Follow the rationale: 1. Nation states ultimately control three key infrastructure pieces required to run data centers (a) land (protected by sovereign armed forces) (b) internet / internet infra (c) electricity. If crypto ever became a legitimate threat, nation states could simply seize any one of or all these three…

Putting data centers on ships in international waters would be just as effective at evading government control (i.e. not very) while being orders of magnitude easier and cheaper to build and operate.

Re: Datacenters in space aren't going to work

#179

Post by wat10000 »

MadnessASAP wrote: post #142
jcranmer wrote: post #109

Earlier quoted context omitted.

Strictly speaking, the thermosphere is actually much warmer than the atmosphere we experience--on the order of 100's or even a 1000 degrees Celsius, if you're measuring by temperature (the average kinetic energy of molecules). However, since particle density is so low, the number of molecules is quite low, and so total heat content of the thermosphere is low. But since particle count is low, conduction and convection…

Technically radiation cooling is 100% efficient. And remarkably effective, you can cool an inert object to the temperature of the CMBR (4K) without doing anything at all. However it is rather slow and works best if there's no nearby planets or stars. Fun fact though, make your radiator hotter and you can dump just as much if not more energy then you would typically via convective cooling. At 1400C (just below the mel…

How much power would a square meter at 1400C shed from convection?

Re: Datacenters in space aren't going to work

#180

Post by wat10000 »

andrewflnr wrote: post #174
foobarian wrote: post #163

Earlier quoted context omitted.

Pardon, but the question of "could the operational cost be smaller in space" is almost not touched at all in the article. The article mostly argues that designing thermal management systems for space applications is hard, and that the radiators required would be big, which speaks to the upfront investment cost, not ongoing opex.

Ok, sure, technically. To be fair you can't really assess the opex of technology that doesn't exist yet, but I find it hard to believe that operating brand new, huge machines that have to move fluid around (and not nice fluids either) will ever be less than it is on the surface. Better hope you never get a coolant leak. Heck, it might even be that opex=0 still isn't enough to offset the "capex". Space is already hard…

Maintenance will be impossible or at least prohibitively expensive. Which means your only opex is ground support. But it also means your capex depreciates over whatever lifetime these things will have with zero repairs or preventive maintenance.
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