Solar-Based Space Power

Hello! I hope you are all doing as well as possible right now. Since many of us are stuck inside for the time being, I’m going to try to revive this blog a bit.

For this first post, let’s talk about space-based solar power. The idea is a popular one; it is exciting (outer space!) and has some logic to it (there are no clouds, nights, seasons, or land-use-constraints in space!). Sadly, though, if you look into the topic – for example, if you read this very well-thought-out piece from Do The Math –  you see that even with extremely optimistic assumptions, it seems unlikely that sending energy from solar panels located in space to earth will become economically worthwhile any time soon, if ever.

And yet, perhaps these analyses are missing something. From what I can see — with the huge, twin caveats that I haven’t looked too deeply into the subject, and that I understand almost nothing about the physics involved in it — recent discussions about space-based wireless power transmission have been limited almost entirely to the idea of generating power in space and sending it to earth in order to provide civilians with clean, reliable energy. There might, however, be alternative uses and methods for wirelessly-transmitting energy via space. For example:

  •  sending space-based solar power to military outposts, in order to provide soldiers with power that is not reliant on vulnerable supply lines, is not bulky to haul around from place to place, and is not intermittent. This is how I first heard about the topic of space-based solar power: George Friedman discusses it in his book The Next 100 Years.
  • the same purpose as above, except that instead of the military outpost receiving power that is generated from space-based solar panels, it would instead receive power that is generated conventionally on earth, then ‘triangulated’: sent up to space, then back down to a different location on earth. Such a system could perhaps also work in tandem with space-based solar panels. Over time, for example, more panels could be launched, so that as the years go by the system would use more power generated in space and less power generated on earth.
  • If the system was located as an array of satellites in Low Earth Orbit (500-2000 km),  rather than much further away in Geosynchronous orbit (40,000 km), having the system use power generated by earth-based sources might allow it to provide power 24/7, as would otherwise not be possible for a Low Earth Orbit system because Low Earth Orbit satellites’ ability to receive sunlight is often blocked by the earth
  • Because wars are themselves intermittent, a space-energy system built for military purposes might be able to double as a civilian system during times when military demand is low. It might be able to help provide power to remote areas in the wake of a natural disaster, for example, which might useful if the disaster (forest fires, perhaps?) is also limiting the remote area’s ability to receive power from other sources, such as from sunlight or  airdrops of fuel or batteries.
  • If the system was built as an array of satellites in Low Earth Orbit, rather than in Geosynchronous orbit, then each satellite in the array would only pass over a given military outpost or region on earth for a very short amount of time.  Most of each satellite’s orbit in such a system might be freed up for non-military uses as result.
  • There is also the question of how to provide satellites with energy, so that satellites themselves can be powered, both for military and non-military reasons. Militarily, for example, if satellites were to be physically attacked, it might perhaps be the case that their ability to protect themselves from any incoming projectiles or debris (the debris perhaps deliberately created by a rival military) would depend on whether or not they have more energy available to them than do the projectiles or debris, which they could then outmaneuver. Thus it might be useful for satellites to receive power wirelessly, either from earth or from other satellites. And again, once such a system is built, it might also be able to find non-military uses.  And perhaps it could also be used to power locations on earth
  • A satellite could perhaps use power generated from its solar panels to create high-energy lasers, in order to destroy any incoming projectiles or debris. A ground-based laser might similarly be used to destroy incoming projectiles or debris threatening a low-earth-orbit satellite. The same lasers might then also be used offensively, to attack rival satellites, or to attack rival targets on earth. They might also be used to provide power from earth to a satellite, or from one satellite to another. This could perhaps be useful if the satellites that are receiving the power are following orbits that spend little to no time in sunlight. It might also be useful if the satellites receiving power are intended to be as small in size as possible (perhaps in order to provide a smaller target for debris or projectiles to hit) and so cannot have big solar panels or batteries or fuel tanks.

Obviously, I have absolutely no idea what I’m talking about here. So I’m asking, is there anything to these ideas? Are there other similar ideas that I’ve left out? How might these factors change the math when it comes to thinking about the future economics of energy in space?

Finally, if the civilians-piggybacking-on-the-military-surplus-capacity-of-triangulating-energy-from-earth-to-space-back-to-earth idea is anything other than totally ridiculous, which power sources would be best suited for it? Would solar panel companies in the Australian Outback benefit, for example, by being able to wirelessly send their otherwise-remote, Southern Hemisphere-summer energy to military and/or civilian locations in space, or and perhaps then on to other places back on earth?

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