Comment by eldenring
14 hours ago
Solar in space is a very different energy source in terms of required infrastructure. You don't need batteries, the efficiency is much higher, cooling scales with surface area (radiative cooling doesn't work as well through an atmosphere vs. vacuum), no weather/day cycles. Its a very elegant idea if someone can get it working.
Only if you also disregard all the negatives.
The panels suffer radiation damage they don't suffer on Earth. If this is e.g. the same altitude orbits as Starlink, then the satellites they're attached to burn up after around tenth of their ground-rated lifetimes. If they're a little higher, then they're in the Van Allen belts and have a much higher radiation dose. If they're a lot higher, the energy cost to launch is way more.
If you could build any of this on the moon, that would be great; right now, I've heard of no detailed plans to do more with moon rock than use it as aggregate for something else, which means everyone is about as far from making either a PV or compute factory out of moon rock as the residents of North Sentinel Island are.
OK, perhaps that's a little unfair, we do actually know what the moon is made of and they don't, but it's a really big research project just to figure out how to make anything there right now, let alone making a factory that could make them cost-competitive with launching from Earth despite the huge cost of launching from Earth.
> The panels suffer radiation damage they don't suffer on Earth.
I don't think this is true, Starlink satellites have an orbital lifetime of 5-7 years, and GPUs themselves are much more sensitive than solar panels for rad damage. I'd guess the limiting factor is GPU lifetime, so as long as your energy savings outpace the slightly faster gpu depreciation (maybe from 5 -> 3 years) plus cost of launch, it would be economical.
I've said this elsewhere, but based on my envelope math, the cost of launch is the main bottleneck and I think considerably more difficult to solve than any of the other negatives. Even shielding from radiation is a weight issue. Unfortunately all the comments here on HN are focused on the wrong, irrelevant issues like talking about convection in space.
> I don't think this is true, Starlink satellites have an orbital lifetime of 5-7 years,
That's better than I thought, but still means their PV is only lasting order-of 20% of their ground lifespans, so the integrated lifetime energy output per unit mass of PV isn't meaningfully improved by locating them in space, even if they were launched by an efficient electromagnetic system rather than by a rocket.