Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Economics of Orbital vs. Terrestrial Data Centers

andrewmccalip.com

Post reply on HN
Print view View original

251–260 of 282 posts

Re: Economics of Orbital vs. Terrestrial Data Centers

#251

Post by adrian_b »

DoctorOetker wrote: post #235
PeterHolzwarth wrote: post #132

Earlier quoted context omitted.

"space is cold" I've always enjoyed thinking about this. Temperature is a characteristic of matter. There is vanishingly little matter in space. Due to that, one could perhaps say that space, in a way of looking at it, has no temperature. This helps give some insight into what you mention of the difficulties in dealing with heat in space - radiative cooling is all you get. I once read that, while the image we have in…

Assuming merely attitude control, sure only radiative cooling is available, but its very easy to design for arbitrary cooling rates assuming any given operating temperature: Budget the solar panel area as a function of the maximum computational load. The rest of the satellite must be within the shade of the solar panel, so it basically only sees cold space, so we need a convex body shape, to insure that every surface…

Making the pyramid arbitrarily long and sharp will arbitrarily diminish the heat conductance through the pyramid, so the farther from the pyramid base, the colder it will be and the less it will radiate.

So no, you cannot increase too much the height of the pyramid, there will be some optimum value at which the pyramid will certainly not be sharp. The optimum height will depend on how much of the pyramid is solid and which is the heat conductance of the material. Circulating liquid through the pyramid will also have limited benefits, as the power required for that will generate additional heat that must be dissipated.

A practical radiation panel will be covered with cones or some other such shapes in order to increase its radiating surface, but the ratio in which the surface can be increased in comparison with a flat panel is limited.

Re: Economics of Orbital vs. Terrestrial Data Centers

#252

Post by adrian_b »

yetihehe wrote: post #244
DoctorOetker wrote: post #235

Earlier quoted context omitted.

Assuming merely attitude control, sure only radiative cooling is available, but its very easy to design for arbitrary cooling rates assuming any given operating temperature: Budget the solar panel area as a function of the maximum computational load. The rest of the satellite must be within the shade of the solar panel, so it basically only sees cold space, so we need a convex body shape, to insure that every surface…

> The rest of the satellite must be within the shade of the solar panel, Problem is with solar panels themselves. When you get 1.3kW of energy per square meter and use 325w of that for electricity (25% efficiency) that means you have to get rid of almost 1kW of energy for each meter of your panel. You can do it radiatively with back surface of panels, but your panels might reach equilibrium at over 120°C, which means…

When the cost of the solar panels does not matter you can reach an efficiency close to 50% (with multi-junction solar cells) and the panels will also be able to work at higher temperatures.

Nevertheless, the problem described by you remains, the panels must dissipate an amount of heat at least equal with the amount of useful power that is generated. Therefore they cannot have other heat radiators on their backside, except those for their own heat.

Re: Economics of Orbital vs. Terrestrial Data Centers

#253

Post by jdhwosnhw »

kristianbrigman wrote: post #237
yabones wrote: post #51

Earlier quoted context omitted.

Yeah, I don't see a way to get around the fact that space is a fabulous insulator. That's precisely how expensive insulated drink containers work so well. If it was just about cooling and power availability, you'd think people would be running giant solar+compute barges in international waters, but nobody is doing that. Even the "seasteading" guys from last decade. These proposals, if serious, are just to avoid plann…

But heat = energy, right? So maybe we don’t really want to radiate it, but redirect it back into the system in a usable way and reduce how much we need to take in? (From the sun etc)

Useful, extractable energy comes from a temperature differential, not just temperature itself. Once your system is at temperature equilibrium, you cant extract energy anymore and must shed that temperature as heat

Re: Economics of Orbital vs. Terrestrial Data Centers

#254

Post by fulafel »

yetihehe wrote: post #245
fulafel wrote: post #233

Earlier quoted context omitted.

Related: what color is space?

It's "Cosmic latte". https://en.wikipedia.org/wiki/Cosmic_latte

I saw that too but wonder if it's different for the sparse matter in the interstellar medium, excluding the visible objects.

Re: Economics of Orbital vs. Terrestrial Data Centers

#255

Post by physicles »

lifeisstillgood wrote: post #153

I am struggling with a why for this (other than “huh cool, that will get investors”). All the jurisdiction and regulation arguments and the “we could get the costs down” seem to meet the objection of “for the same investment we could do just as well or better on the ground”. The one that does not is the physics of the whole thing. I struggle to work out how exactly but being slightly time dilated compared to the grou…

I’m not one for conspiracy theories, but since SpaceX is the only launch services provider that could actually put one of these in orbit, this smells a lot like hyperloop to me — an unserious proposal that serves as a distraction and furthers Musk’s aims, and benefits anyone who can get close enough to the piles of cash that VCs will drop on this.

You know what’s easier and cheaper than putting a data center in space? Putting one literally anywhere else other than space.

Re: Economics of Orbital vs. Terrestrial Data Centers

#256

Post by jaywee »

danpalmer wrote: post #103
wmf wrote: post #87

Earlier quoted context omitted.

I think they last 2-3 years after they run out of argon fuel , so more like 7-8 years total. It looks like some Starlinks from Nov 2019 are still operational.

My understanding was that anything at ~500km needed readjustments every few months in order to not come down. Much less than 2-3 years. I'd be interested to know what the average lifespan or failure rate of Starlink has been. That's good that some are still up there 6+ years later, but I know many aren't. I'm not sure how many of those ran out of fuel, had hardware failures, or were simply obsolete, but an AFR would…

Jonathan McDowell keeps track of all the Starlink Sat orbits, including failures:

https://planet4589.org/space/con/star/stats.html

Re: Economics of Orbital vs. Terrestrial Data Centers

#257

Post by clickety_clack »

On the ground you don’t have to fling tons of sensitive electronics to orbital speeds, you can have someone pop by to check whether everything is ok if you get an alert, you have a thick atmosphere cutting down solar radiation, you can cool everything relatively cheaply, and you can run fiber and power cables directly into the building. In space ou have to design super robust and self maintaining machinery. It’s a cool marketing stunt, but I don’t get the economics behind doing it for real.

Re: Economics of Orbital vs. Terrestrial Data Centers

#258

Post by zeofig »

bee_rider wrote: post #214
zeofig wrote: post #139

Earlier quoted context omitted.

A perfect vacuum might have no temperature, but space is not a perfect vacuum, and has a well-defined temperature. More insight would be found in thinking about what temperature precisely means, and the difference between it and heat capacity.

I think your second sentence is what they were referencing. Space has a temperature. But because the matter is so sparse and there’s so little thermal mass to carry heat around as a result, we don’t have an intuitive grasp on what the temperature numbers mean.

I think otherwise.

Re: Economics of Orbital vs. Terrestrial Data Centers

#259

Post by Nevermark »

krisoft wrote: post #202
Nevermark wrote: post #131

Earlier quoted context omitted.

So just 13.3 million sq. meters of solar panels, and 6.67 million sq. meters of cooling panels for 1 GW. Or a 3.651 km squared and 2.581 km squared butterfly sattelite. I don't think your cooling area measures account for the complications introduced by scale. Heat dissipation isn't going to efficiently work its way across surfaces at that scale passively. Dissipation will scale very sub-linearly, so we need much mor…

> active fluid exchangers operating at speed spanning kilometers of real estate, to get dissipation/area anywhere back near linear/area again Could the compute be distributed instead? Instead of gathering all the power into a central location to power the GPUs there, stick the GPUs on the back of the solar panels as modules? That way even if you need active fluid exchanger it doesn’t have to span kilometers just mete…

> Could the compute be distributed instead?

For electrons that would dramatically increase latency, and lower bandwidth, slowing down compute.

Maybe dense optical connects could work?

Re: Economics of Orbital vs. Terrestrial Data Centers

#260

Post by remarkEon »

eldenring wrote: post #137
zozbot234 wrote: post #19

Will these space-based data centers run on rad-hard silicon (which is dog slow compared to anything on Earth) or just silently accept wrong results, hardware lockups and permanent failure due to the harsh space environment? Will they cool that hardware with special über-expensive high-temperature Peltiers that heat the radiators up to visible incandescence so that the heat can be shed with any efficiency? There's zil…

Google did a study with their TPU v6 > For ML accelerators to be effective in space, they must withstand the environment of low-Earth orbit. We tested Trillium, Google’s v6e Cloud TPU, in a 67MeV proton beam to test for impact from total ionizing dose (TID) and single event effects (SEEs). > > The results were promising. While the High Bandwidth Memory (HBM) subsystems were the most sensitive component, they only beg…

Do you have a link to this?
Post reply on HN