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Thread: AdAstra on Solar Power Satellites

  1. #1
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    AdAstra on Solar Power Satellites

    I've found this gem, so I thought I will share.

    Here is a special issue of the AdAstra magazine from 2008 discussing solar power satellites. 36 pages, straight from the publisher: http://www.nss.org/adastra/AdAstra-SBSP-2008.pdf

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    I love those historical quotes from skeptics and naysayers that turned out false, in-the-end.

    I didn't know that Lee DeForest was procecuted for mail fraud but, as I found out since reading this post; acquitted.

    As for the subject at-hand; I would very much like to see someone spend startup capital on such a venture. I would certainly invest in the company when they went public.

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    I don't see the real advantage of this compared to Earth based solar power. Yes, you lose some efficiency from the atmosphere, but you lost some efficiency transmitting the power ground.
    Given the costs of putting things in orbit and the fact that solar cells degrade after a while, what exactly are the advantages beyond constant sunlight?

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    You wouldn't have to use solar cells. Concentrated sunlight on solar heat engines to mechanically generate the electricity could be used, don't know how they'd compare in efficiency, but solar cells aren't too high up themselves.

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    Quote Originally Posted by Rhaedas View Post
    You wouldn't have to use solar cells. Concentrated sunlight on solar heat engines to mechanically generate the electricity could be used, don't know how they'd compare in efficiency, but solar cells aren't too high up themselves.
    Hmm, that is true. However, now you are adding mechanical complexity as any solar thermal generator (unless you are using the *very* low efficiency of direct conversion) is going to need moving parts.

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    Only a few, and the main wear in generator parts is usually the bearings, I believe. In zero g, that's a lot less wear.

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    Quote Originally Posted by Rhaedas View Post
    Only a few, and the main wear in generator parts is usually the bearings, I believe. In zero g, that's a lot less wear.
    Still, it's more things that can go wrong, so you probably want some people on-site to watch and maintain things. You can't have the power go out because the generator seized.
    Which adds exponentially to the complexity.

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    Hopefully in building such a thing, we'd have to create not only an infrastructure to support the construction, but living environments for those building, and then later, maintaining it. That was the bigger picture of the O'Neill colonies of the 70s.

    But you're missing something. A failure of one of the generators wouldn't be a huge loss, as it isn't one big one, but a large arrays of them, so there's a lot of redundancy. But you would need the ability to fix what does break. That's always been true, but only a few cases have we been able to do that (like the Hubble).

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    Quote Originally Posted by ravens_cry View Post
    I don't see the real advantage of this compared to Earth based solar power. Yes, you lose some efficiency from the atmosphere, but you lost some efficiency transmitting the power ground.
    I think the article could have covered that better.

    The biggest issue with ground based solar power is the substantial variability. You have the day/night cycle, of course. Up to 10 to 20%, solar can match summer peak demand fairly well (you get the most sunlight when you want to run the air conditioner), but in winter not so much (peak is usually after dark when people run the electric stove/oven/microwave/etc. to cook dinner). Also, most locations, available solar in winter is substantially lower than summer. And there is weather.

    So, anyway, if you have maybe 10 to 20% of the electrical supply as ground based solar, it can be fairly useful replacing other peak supply. If you want to go above using it for peaking supply it gets trickier. You start to need substantial energy storage, which adds cost and reduces efficiency (energy storage is a big research area right now - we need better energy storage). Unless you have alternatives, you probably need to substantially oversize the total system unless you're willing to live with blackouts or (maybe with smartgrids) dramatically variable use.

    Now, it can help if you can put the panels in a sunny desert someplace then feed it to the grid to be picked up in less suitable locations, but another issue there is: Whose desert are you using? For big countries with appropriate areas, it might not be as big a deal, but if you live in a country with no really suitable locations for solar, you'd need to import it, which means security issues, and you have to pay to import it.

    Space based solar could supply about the same energy year around. Countries without suitable ground locations could still own their own solar power satellites. And it would be good if everyone had a good non-fossil, non-nuclear baseload supply option (while I support nuclear, I would be happy if it could be minimized).

    The problem, of course, is economics. The early concepts were very massive, with huge human crews to build them. However, there has been a lot of recent thought on lowering the mass and making them easier to build without large human crews, which substantially improves the economic argument. I don't know if it has been improved enough, but I think the case has gotten a lot stronger for them.

    "The problem with quotes on the Internet is that it is hard to verify their authenticity." Abraham Lincoln

    I say there is an invisible elf in my backyard. How do you prove that I am wrong?

    The Leif Ericson Cruiser

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    Well, for an O'Neill or other outpost, it's much more suitable as it requires much less resources to maintain than other means of generating power.
    I just don't see it being useful for Earth. Lots of smaller stations adds redundancy, but it also adds more things that can go wrong.
    AdAstra would be an awesome name for a Superman knock-off.

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    Quote Originally Posted by Van Rijn View Post
    I don't know if it has been improved enough, but I think the case has gotten a lot stronger for them.
    The cost of building and launching space qualified hardware is still hugely, massively expensive.

    I don't see how anyone can possibly suggest, with a straight face, that it's more economical to do that than generate electricity by renewable means on Earth.

    Note - the alternative to space based solar power is not earth based solar power (far more economically viable though I consider that to be).... it's any renewable on-Earth solution.

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    Quote Originally Posted by ravens_cry View Post
    AdAstra would be an awesome name for a Superman knock-off.
    There is a superheroine named Adastra.

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    Quote Originally Posted by djellison View Post
    The cost of building and launching space qualified hardware is still hugely, massively expensive.
    But that doesn't mean it must always be so. Building a small unique spacecraft is one thing, but building a million spacecraft (or a million solar panels) is another.

    I don't see how anyone can possibly suggest, with a straight face, that it's more economical to do that than generate electricity by renewable means on Earth.
    I think it's an important enough issue that it shouldn't be dismissed out of hand. There's no physical reason why it can't work, and the economics depend on the details of design and current technology. I'd want to see a *good* business case made, but I won't just assume that it must be impossible.

    "The problem with quotes on the Internet is that it is hard to verify their authenticity." Abraham Lincoln

    I say there is an invisible elf in my backyard. How do you prove that I am wrong?

    The Leif Ericson Cruiser

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    Quote Originally Posted by KaiYeves View Post
    There is a superheroine named Adastra.
    Interesting, I'll have to check that out sometime. I was thinking if someone mixed Deep Space Nine's Odo, someone whose natural form was an amorphous blob, with Superman, with a little The Iron Giant as it eventually comes out he, if he is the right word, was sent to Earth as a weapon, but becomes its protector instead.
    Yeah, major off topic I know.
    Carry on.

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    A SPSS is a solar Electric spacecraft at end of life perhaps. If nothing else, it is a heck of a platform for radio bounce--an Orbital antenna farm location, etc.

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    I Thought about something : One big advantage of solar power satellites is that the light is said to be constant. I know there is no night and no clouds in high orbit , the sun shines eternally. But practically How that can be used ? The satellites are orbiting the Earth , in may 24 hours , if they are on GTO orbit. So to keep insulation constant the panels must rotate accordingly. The big and flimsy 1 Km wide or more panels are turning to keep the sun light hitting them strait on and all the rest of the satellite with the transmiting antenna must stay focused on earth.

    Is it possible ? how it can be done ?

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    JAXA seem to be the ones taking this most seriously.
    Difficult to find much about the engineering.
    just managed to find this, which is mostly PR, but it at least visualises it.



    the thing i thought would most derail this was the safety aspect, but those involved seem to thing thats not such a big issue, saying you could stand in the beam for short periods and suffer no ill effects. I dont quite understand that, but will take their word for it

  19. #19
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    Perhaps the SPSS sats beam their power to geostationary platforms with that being beamed straight down 24/7

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