Comment by __alexs
7 hours ago
Solar cells have exactly the same power rating on earth as in space surely? What would change is their capacity factor and so energy generation.
7 hours ago
Solar cells have exactly the same power rating on earth as in space surely? What would change is their capacity factor and so energy generation.
Satellites can adjust attitude so that the panels are always normal to the incident rays for maximum energy capture. And no weather/dust.
You also don't usually use the same exact kind of panels as terrestrial solar farms. Since you are going to space, you spend the extra money to get the highest possible efficiency in terms of W/kg. Terrestrial usually optimizes for W/$ nameplate capacity LCOE, which also includes installation and other costs.
For one or a few-off expensive satellites that are intended to last 10-20 years, then yes. But in this case the satellites will be more disposable and the game plan is to launch tons of them at the lowest cost per satellite and let the sheer numbers take care of reliability concerns.
It is similar to the biological tradeoff of having a few offspring and investing heavily in their safety and growth vs having thousands off offspring and investing nothing in their safety and growth.
The atmosphere is in the way, and they get pretty dirty on earth. Also it doesn't rain or get cloudy in space
Sure but like, just use even more solar panels? You can probably buy a lot of them for the cost of a satellite.
The cost of putting them up there is a lot more than the cost of the cells
I think it's because at this scale a significant limit becomes the global production capacity for solar cells, and SpaceX is in the business of cheaper satellites and launch.
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And in geostationary, the planet hardly ever gets in the way. They get full sun 99.5% of the year.
even at 10% (say putting it on some northen pile of snow) it is still cheaper to put it on earth than launch it
I don't disagree
I'm all for efficiency, but I would think a hailstorm of space junk hits a lot harder than one of ice out on the farm.
Except it doesn't melt like regular hail so when further storms come up you could end being hit by the same hail more than once :\
Solar modules you can buy for your house usually have quoted power ratings at "max STC" or Standard Testing Conditions, which are based on insolation on Earth's surface.
https://wiki.pvmet.org/index.php?title=Standard_Test_Conditi...
So, a "400W panel" is rated to produce 400W at standard testing conditions.
I'm not sure how relevant that is to the numbers being thrown around in this thread, but thought I'd provide context.
Atmospheric derating brings insolation from about 1.367KW/m2 to about 1.0.
And then there’s that pesky night time and those annoying seasons.
It’s still not even remotely reasonable, but it’s definitely much higher in space.
> And then there’s that pesky night time and those annoying seasons.
The two options there are cluttering up the dawn dusk polar orbit more or going to high earth orbit so that you stay out of the shadow of the earth... and geostationary orbits are also in rather high demand.
Put them super super far away and focus all the energy into one very narrow death laser that we trust the tech company to be careful with.