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Solar panels in space are more efficient, but on the ground we have dead dinosaurs we can burn. The efficiency gain is also more than offset by the fact that yo

Solar panels in space are more efficient, but on the ground we have dead dinosaurs we can burn. The efficiency gain is also more than offset by the fact that you can't replace a worn out panel. A few years into the life of your satellite its power production drops.

duskwuff 9mo ago
> Solar panels in space are more efficient... ... if you completely ignore the difficulty of getting them up there. I'd be interested to see a comparison between the amount of energy required to get a solar panel into space, and the amount of energy it produces during its lifetime there. I wouldn't be surprised if it were a net negative; getting mass into orbit requires a tremendous amount of energy, and putting it there with a rocket is not an efficient process.
- obidee2 9mo ago
  My sketchy napkin math gives an order of magnitude of a few months of panel output to get it in space. 5kg, 500W panel (don’t exactly know what the ratio is for a panel plus protection and frame for space, might be a few times better than this) Say it produces about 350kWh per month before losses. Mass to LEO is something like 10x the weight in fuel alone, so that’s going to be maybe 500kWh. Plus cryogenics etc. So not actually that bad
serallak 9mo ago
If they plan to put this things in a low orbit their useful life before reentry is low anyway. A quick search gave me a lifespan of around 5 years for a starlink satellite. If you put in orbit a steady stream of new satellites every year maintenance is not an issue, you just stop using worn out or broken ones.
- kibwen 9mo ago
  Terrestrial data centers save money and recoup costs by salvaging and recycling components, so what you're saying here is that space-based datacenters are even less competitive than we previously estimated.
ericd 9mo ago
No idea how quickly they wear out in space with 24x7 irradiance and space temps, but on the earth, they’re at something like 80% capacity after 25 years. So seems like you could control how long they have via overpanelling?

duskwuff 9mo ago

> Solar panels in space are more efficient... ... if you completely ignore the difficulty of getting them up there. I'd be interested to see a comparison between the amount of energy required to get a solar panel into space, and the amount of energy it produces during its lifetime there. I wouldn't be surprised if it were a net negative; getting mass into orbit requires a tremendous amount of energy, and putting it there with a rocket is not an efficient process.

obidee2 9mo ago
My sketchy napkin math gives an order of magnitude of a few months of panel output to get it in space. 5kg, 500W panel (don’t exactly know what the ratio is for a panel plus protection and frame for space, might be a few times better than this) Say it produces about 350kWh per month before losses. Mass to LEO is something like 10x the weight in fuel alone, so that’s going to be maybe 500kWh. Plus cryogenics etc. So not actually that bad

serallak 9mo ago

If they plan to put this things in a low orbit their useful life before reentry is low anyway. A quick search gave me a lifespan of around 5 years for a starlink satellite. If you put in orbit a steady stream of new satellites every year maintenance is not an issue, you just stop using worn out or broken ones.

kibwen 9mo ago
Terrestrial data centers save money and recoup costs by salvaging and recycling components, so what you're saying here is that space-based datacenters are even less competitive than we previously estimated.

ericd 9mo ago

No idea how quickly they wear out in space with 24x7 irradiance and space temps, but on the earth, they’re at something like 80% capacity after 25 years. So seems like you could control how long they have via overpanelling?