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1. alangi+u6[view] [source] 2026-02-02 22:13:48
>>g-mork+(OP)
Either this is a straight up con, or Musk found a glitch in physics. It's extremely difficult to keep things cold in space.
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2. Doctor+Ca[view] [source] 2026-02-02 22:29:03
>>alangi+u6
what makes you believe this?

radiators can be made as long as desirable within the shade of the solar panels, hence the designer can pracitically set arbitrarily low temperatures above the background temperature of the universe.

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3. eldenr+Ub[view] [source] 2026-02-02 22:33:14
>>Doctor+Ca
these same comments pop up every time someone brings up satellite data-centers where people just assume the only way of dissipating heat is through convection with the environment.
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4. wat100+Md[view] [source] 2026-02-02 22:39:18
>>eldenr+Ub
No, we just "assume" (i.e. know) that radiation in a vacuum is a really bad way of dissipating heat, to the point that we use vacuum as a very effective insulator on earth.

Yes, you can overcome this with enough radiator area. Which costs money, and adds weight and space, which costs more money.

Nobody is saying the idea of data centers in space is impossible. It's obviously very possible. But it doesn't make even the slightest bit of economic sense. Everything gets way, way harder and there's no upside.

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5. eldenr+Nf[view] [source] 2026-02-02 22:47:19
>>wat100+Md
The radiators would be lighter compared to the solar panels, and slightly smaller surface area so you can line them back to back

I don't think dissipating heat would be an issue at all. The cost of launch I think is the main bottleneck, but cooling would just be a small overhead on the cost of energy. Not a fundamental problem.

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6. wat100+9p[view] [source] 2026-02-02 23:25:02
>>eldenr+Nf
The pertinent thing is that it’s not an advantage. It may be doable but it’s not easier than cooling a computer in a building.
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7. Doctor+bT[view] [source] 2026-02-03 02:23:04
>>wat100+9p
The distinction is that you don't need to compete for land area, that you don't cause local environmental damage by heating say a river or a lake, that you don't compete with meatbags for energy and heat dissipation rights.

Without eventually moving compute to space we are going to have compute infringe on the space, energy, heat dissipation rights of meatbags. Why welcome that?!?

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8. defros+pU[view] [source] 2026-02-03 02:31:58
>>Doctor+bT
How efficient is thermal radiation through a vacuum again?

Sure, it occurs, but what does the Stefan–Boltzmann law tell us about GPU clusters in space?

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9. Doctor+9V[view] [source] 2026-02-03 02:37:13
>>defros+pU
> How efficient is thermal radiation through a vacuum again?

I provided the calculation for the pyramidal shape: if the base of a pyramid were a square solar panel with side length L, then for a target temperature of 300K (a typical back of envelope substitute for "room temperature") the height of the pyramid would have to be about 3 times the side length of the square base. Quite reasonable.

> Sure, it occurs, but what does the Stefan–Boltzmann law tell us about GPU clusters in space?

The Stefan-Boltzmann law tells us that whatever prevents us from putting GPU clusters in space, it's not the difficulty in shedding heat by thermal radiation that is supposedly stopping us.

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10. defros+EV[view] [source] 2026-02-03 02:40:55
>>Doctor+9V
Is it the required size of the wings for radiative cooling then?
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11. Doctor+IX[view] [source] 2026-02-03 02:58:28
>>defros+EV
Just picture a square based pyramid, like a pyramid from egypt, thats the rough shape. Lets pretend the bottom is square. For thermodynamic analysis, we can just pretend the scale is irrelevant, it could be 4 cm x 4 cm base or 4 km x 4 km base. Now stretch the pyramid so the height of the tip is 3 times the length of the sides of the square base, so 12 cm or 12 km in the random examples above.

If the base were a solar panel aimed perpendicular to sun, then the tip is facing away and all side triangles faces of the pyramid are in the shade.

I voluntarily give up heat dissipation area on 2 of the 4 triangular sides (just to make calculations easier, if we make them thermally reflective -emissivity 0-, we can't shed heat, but also don't absorb heat coming from lukewarm Earth).

The remaining 2 triangular sides will be large enough that the temperature of the triangular panels is kept below 300 K.

The panels also serve as the cold heat baths, i.e. the thermal sinks for the compute on board.

Not sure what you mean with wings, I intentionally chose a convex shape like a pyramid so that no part of the surface of the pyramid can see another part of the surface, so no self-obstruction for shedding heat etc...

If this doesn't answer your question, feel free to ask a new question so I understand what your actual question is.

The electrical power available for compute will be approximately 20% (efficiency of solar panels) times the area of the square base L ^ 2 times 1360 W / m ^ 2 .

The electrical power thus scales quadratically with the chosen side length, and thus linearly with the area of the square base.

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12. queenk+zW1[view] [source] 2026-02-03 11:33:31
>>Doctor+IX
So how big are you proposing the solar panel be to be able to provide 1GW to the GPUs? Nearly a square kilometer? With an additional 3 square kilometers of radiators?

Yeah doesn't sound particularly feasible, sorry. Glad you know all the math though!

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13. Doctor+262[view] [source] 2026-02-03 12:33:32
>>queenk+zW1
I made an example calculation at >>46867402

For a 230 kW cluster: 16 x DGX (8x)B200; we arrived at a 30m x 30m solar PV area, and a 90 meter distance from the center of the solar array to the tip of the pyramid.

1 GW = 4348 x 230 kW

sqrt(4348)= ~66

so launch 4348 of the systems described in the calculation I linked, or if you insist on housing them next to each other:

the base length becomes 30 m x 66 = 1980 m = ~ 2 km. the distance from center of square solar array to the tip of the pyramid became 6 km...

any of these systems would need to be shipped and collected in orbit and then assembled together.

a very megalomaniac endeavor indeed.

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14. gilbet+8q2[view] [source] 2026-02-03 14:35:59
>>Doctor+262
Musk wants to put up 500-1000 TW per year. Even 1 TW would be 4.348 million of your systems. Even one of your clusters is at the edge of what we've built, and you talk about snapping 4000 of them together as if they were legos.

To run just one cluster (which would be generally a useless endeavor given it is just a few dozen GPUs) would be equivalent to the best we've ever done, and you wonder why you're being downvoted? Your calculations, which are correct from a scientific (but not engineering) standpoint, don't support the argument that it is possible, but rather show how hard it is. I can put the same cluster in my living room and dissipate the heat just fine, but you require a billion dollar system to do it in space.

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15. Doctor+726[view] [source] 2026-02-04 13:05:40
>>gilbet+8q2
I really don't recommend you continuously dissipate 230 kW in your living room, your insurer would certainly like to be informed of such a thing.
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16. direwo+a46[view] [source] 2026-02-04 13:18:25
>>Doctor+726
It's only illegal if you get caught. Your insurer only needs to know if your house burns down. Don't burn your house down while this is set up in your living room.
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