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Comment by LargoLasskhyfv | Hacker News Reader

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LargoLasskhyfv

So what?

I give you Space Grid ©.

[1] https://en.wikipedia.org/wiki/Space-based_solar_power

edit: I don't know why that symbol doesn't show as copyleft as intended.

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Space advocates seem to have been going off the idea of that over the past few years. I'm not sure how much of that is due to a better appreciation of the downsides, and how much is due to the very rapid improvements we've been seeing in ground-based solar.

A couple of recent (late 2019) articles from Casey Handmer:

https://caseyhandmer.wordpress.com/2019/08/20/space-based-so...

https://caseyhandmer.wordpress.com/2019/09/20/no-really-spac...

It's worth reading the comments too; there are some interesting points there, although I think the game-changing ones rely on new tech and/or well-developed lunar industry.

Yes. I'm aware of that. But while economically usable fusion remains SciFi so far, space based solar just lacks some bootstrapping. Which seems to be more attainable as time passes.

If "we" really wanted this, we could do it now because the technology is there. There is no what if like in any path to fusion.

edit: especially considering all the hype about colonizing Mars, or a Moonbase.

Space solar is a way to get the most out of expensive PV cells. But PV is no longer expensive. It's cheaper to just overbuild on Earth and transmit energy through time (storage) rather than through space (microwaves).

That seems like it could have more difficult engineering problems than a fusion reactor! Seems like a quick way to accidentally microwave a desert into a sea of glass. Hope you don't put anything remotely near the power receiver on earth.

Power density on the ground would be way lower than you're thinking.

The leading proposals, like SPS-Alpha, put a gigawatt-scale power station in geostationary orbit. Power is beamed to ground via microwave. The receiver station has to be kilometers wide, which puts the power density low enough so birds wouldn't be harmed; even that amount of focus is only doable by sending a pilot signal from the receiver, so the beam can't trivially be redirected to other targets. Despite its size, the receiver would be inexpensive, since it's mostly wire antennae.

Hey, think positive! If microwaves prove too dangerous, and they finally do manage to build a cable from the orbital power station down to earth, they have a space elevator as well!

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