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Comment by IvyMike | Hacker News Reader

I don't pretend to understand the thermodynamics of all of this to do an actual calculation, but note that the ISS spends half its time in the shadow of the earth, which these satellites would not do.

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The earth is actually a pretty big heat source in space. Solar radiation is a point source, so you can orient parallel to the rays and avoid it. The earth takes up about half the sky and is unavoidable. The earth also radiates infrared, the same as your radiators, so you can't reflect it. Solar light is in the visible spectrum so you can paint your radiators to be reflective in visible wavelengths but emissive in infrared.

Low satellites are still cooler in the Earth's shadow than they would be in unshadowed orbits, but higher orbits are cooler than either. Not where you'd want to put millions of datacenters though.

Wouldn't they?

You would put these in polar orbits so they are always facing the Sun. Basically the longitude would follow the Sun (or the terminator line, whichever you prefer), and the latitude would oscillate from 90°N to 90°S and back every 24 hours.

From the linked article:

> By directly harnessing near-constant solar power

Implies they would not spend half of their time in the dark.

No. Otherwise how would you power them? We could use nuclear power methods, like we did in the Voyagers for instance. But the press release doesn’t mention that and, for a constellation of satellites around the earth, it would be a terrible idea.

NASA doesn't have enough radioactive material for its current needs, RTG is used only for missions far from Sun (and Earth).

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