First here is a picture of one of the ideas
That's an idea from Japan, see
How Japan Plans to Build an Orbital Solar Farm
Then there's the SPS-Alpha
NASA - SPS-ALPHA: The First Practical Solar Power Satellite via Arbitrarily Large PHased Array
You can probably find many more links here
Space-based solar power
(caution - Wikipedia is a secondary source of course, be sure to check out the primary sources if really interested in some particular project).
These modern plans generally seem to be based around a microwave phased array.
Lots of smaller microwave generators - and they all have to target a single spot on the ground - and controlled usually by a guiding beam back from the ground station.
And not targetted by mechanical movements - but by phase differences in the radiation.
That's very safe because if anything goes wrong - then the mirrors just end up not focused anywhere.
They can't accidentally focus on some other spot.
Also - is designed so that even if you walk right through the receiving station - the microwaves you receive doing so are not harmful to human health.
Though you'd probably put the receiving station into a desert, and workers wear protective clothing just in case.
The main thing here I wonder about is, about the timescale, will we be able to do this by 2025 as some of the optimistic projections have it - or will it be quite a bit later (e.g. 2050).
But wouldn't be surprised if we do at some point. It is an obvious thing to do once construction in space becomes easier and less expensive.
It was also the original motivation for the Stanford Torus, they planned to finance it by using the 10,000 inhabitants mainly to build solar satellites in space and beam the power back to Earth - using mainly materials sourced from the Moon to build their habitat sent to them using a mass driver. No t sure about the satellites themselves where they planned to source the materials.
They thought it would pay itself back through sale of electricity within a few decades.
If they had gone ahead and built it, and it had worked, we might already be using solar satellites for much of our power.
Not at all saying this is imminent.
Right now, ground spaced solar is surely the way to go - short of some major breakthrough.
But - still can do research into the space based microwaves - which is what Japan is doing and NASA to some extent. So - maybe 10 years from now, maybe 30 years from now - maybe that research will come to some fruition.
In the future, seems at least possible that space based solar may be part of the mix. Mainly because it is uninterruptable.
Depends.
Or indeed - on a smaller scale - for supplying power to interplanetary and interstellar probes (idea has been suggested, I can't remember where I saw it, with high power density, easy to focus based on pilot beam that the craft could send back to Earth - would be most of the way towards what you need).
I think it is well worth studying and see where it goes. Could be anything from world changing to a minor application in some area of space science.
It's quite controversial at present for near future. But quite a few in Japan at least seem to think it is the next big thing.
I wish them good luck with it and will be interested to learn how it develops!
As for issues of cost - it seems a very expensive way to get solar power at present but that could change if
That's an idea from Japan, see
How Japan Plans to Build an Orbital Solar Farm
Then there's the SPS-Alpha
NASA - SPS-ALPHA: The First Practical Solar Power Satellite via Arbitrarily Large PHased Array
You can probably find many more links here
Space-based solar power
(caution - Wikipedia is a secondary source of course, be sure to check out the primary sources if really interested in some particular project).
These modern plans generally seem to be based around a microwave phased array.
Lots of smaller microwave generators - and they all have to target a single spot on the ground - and controlled usually by a guiding beam back from the ground station.
And not targetted by mechanical movements - but by phase differences in the radiation.
That's very safe because if anything goes wrong - then the mirrors just end up not focused anywhere.
They can't accidentally focus on some other spot.
Also - is designed so that even if you walk right through the receiving station - the microwaves you receive doing so are not harmful to human health.
Though you'd probably put the receiving station into a desert, and workers wear protective clothing just in case.
The main thing here I wonder about is, about the timescale, will we be able to do this by 2025 as some of the optimistic projections have it - or will it be quite a bit later (e.g. 2050).
But wouldn't be surprised if we do at some point. It is an obvious thing to do once construction in space becomes easier and less expensive.
It was also the original motivation for the Stanford Torus, they planned to finance it by using the 10,000 inhabitants mainly to build solar satellites in space and beam the power back to Earth - using mainly materials sourced from the Moon to build their habitat sent to them using a mass driver. No t sure about the satellites themselves where they planned to source the materials.
They thought it would pay itself back through sale of electricity within a few decades.
If they had gone ahead and built it, and it had worked, we might already be using solar satellites for much of our power.
MORE ABOUT IT - IN RESPONSE TO STEVE BLUMENKRANZ'S ANSWER
- They are in geostationary orbit so have a single groundstation - not ground station hopping. E.g. Japan can build a solar power array hovering above Japan.
- The problem of safety is fixed with phased array microwaves. No chance of mis-pointing - as they rely on a pilot beam and without it are not focused anywhere.
- With microwaves can have substantial power transmission with safe levels of radiation - only 10 times the recommended limit for humans in a work place. Workers in the plant can wear protective clothing to shield from microwaves (just as we are shielded from the microwaves inside a microwave oven by Faraday cage type shielding) - and outside - then it tails off rapidly to normal work place permitted levels for microwaves.
- You would be in no danger even if you walked right through it. E.g. if someone visited the plant and forgot to wear the protective clothing. Those 10 times levels are for prolonged exposure in the workspace
Not at all saying this is imminent.
Right now, ground spaced solar is surely the way to go - short of some major breakthrough.
But - still can do research into the space based microwaves - which is what Japan is doing and NASA to some extent. So - maybe 10 years from now, maybe 30 years from now - maybe that research will come to some fruition.
In the future, seems at least possible that space based solar may be part of the mix. Mainly because it is uninterruptable.
Depends.
- Excellent battery storage at low cost or other ways of preserving power from daytime to night time (including liquid salt) -
- Easy long range transport of power - and peaceful world so people are not bothered about living say in Poland or whatever and depending on electricity generated in the Sahara desert and transmitted to them by long range power transmission through many different intermediate countries.
- Could mean that solar power stations in deserts such as Sahara etc produce all our power and we don't need anything else.
Or indeed - on a smaller scale - for supplying power to interplanetary and interstellar probes (idea has been suggested, I can't remember where I saw it, with high power density, easy to focus based on pilot beam that the craft could send back to Earth - would be most of the way towards what you need).
I think it is well worth studying and see where it goes. Could be anything from world changing to a minor application in some area of space science.
It's quite controversial at present for near future. But quite a few in Japan at least seem to think it is the next big thing.
I wish them good luck with it and will be interested to learn how it develops!
As for issues of cost - it seems a very expensive way to get solar power at present but that could change if
- Launch costs go down to a few dollars per ton (some ways this could happen though probably not for another few decades)
- Or space mining takes off in a big way so the bulk of the materials are supplied from space - that includes mining by humans in space as in the Stanford Torus idea - and also - much more capable autonomous or semi-autonomous robots mining in space.
- Or - a bit of a way out idea - but one suggestion is - self replicating solar panels - or - more or less self replicating. Even if you have to ship computer chips and other lightweight components from the Earth - if you could get a big chunk of an NEO, return it to GSO and then have solar powered robots, autonomous, mine it to create solar panels - that could be a game changer.
Of course 3D printing would also be a game changer on Earth which might make the whole thing obsolete. I think space enthusiasts who get carried away with possibilities of 3D printers often forget this.
About the Author
Robert Walker
Writer of articles on Mars and Space issues - Software Developer of Tune Smithy, Bounce Metronome etc.Studied at Wolfson College, Oxford
Lives in Isle of Mull
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