Japan Will Try to Beam Solar Power from Space by 2025 - Slashdot

Posted by EditorDavid

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  Space is 2000 times further (at least)
  Inverse square law means you would get 1 four millionth of the power...

  • This is, obviously, a from of focussed energy beaming. Probably some phased-array thing derived from radar tech.

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    • Re:

      Could be a Klystron.

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    • Re: So they beamed power 50 metres

      The inverse square law is still in effect. Beam divergence at the receiver is inversely proportional to the square of distance, directly proprtional to the square of wavelength, and inversely proportional to the square of the size of the transmitting antenna.

      Either you shrink the wavelength (and incur losses), or increase the transmitter size and incur huge cost increases.

      There is such a thing as an "electromagnetic bullet" that is a solution to Maxwell's Equations that doesn't diverge as it propagates, but

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        When dealing with a power source as massive as the sun, maybe the inefficiencies are okay?

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    I think you should contact them and express your concerns. You might save them a lot of money.

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    Actually, inverse square law means that with the same aperture you will get a four million times larger spot size at the receiver... if the original beam were diffraction limited.

    But at a distance of 50 meters, though, the original beam wouldn't have been diffraction limited, so no, that doesn't apply.

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    They’re using something a bit like a laser (probably beam forming by phased array). And it’s possible to push the focal spot of a beam out to hundreds of kilometers. Yeah, beyond that, intensity drops off by inverse square, but focusing power from space onto a fairly tight spot on the planet’s surface could be feasible.

    
    
    Don’t get me wrong - there are about a hundred OTHER things that I’m skeptical about in terms of making this work. At least, not until launch costs are reduc

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      What the Chinese are discussing is slightly different to what the West wants to do. Western groups want to beam from geosynchronous orbit so that their patch gets all the power, and also to avoid shadow.

      China wants to beam from low orbit, and swap power from site to site as the satellites progress in orbit. Presumably they'll beam between satellites to transfer power into shaded bits. Lossy, but then so is beaming 36,000km.

      Cool thing though is beaming power to spacecraft or lunar colonies.

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    MTG claims the Rothschilds have prior art...

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      Jewish / Japan -- both start with "J". She got something right... #She'sTheWorst

• Presumably you can fry a power-grid or electronics with this. If it is a phased-array type of beam it can be focussed anywhere without visible preparation.

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    An then make a face... Ooops, navigation malfunction... Seriously, we are terribly sorry for that airport/ship yard... and than shiny air carrier you had there...:D
• What could possibly go wrong with beaming energy from space? Wait. Is that a mutant monster rising from the sea? Gogirra! Aiieeee! Power Ranger, help us!

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    There's no need for scaremongering; the systems proposed use rectenna arrays and additionally the amount of energy that would be absorbed by say, a bird flying over the rectenna farm, isn't enough to cook it.

    A satellite would have to fail in multiple ways simultaneously to be a problem - aim would have to drift, the safeties would have to fail to kill the power transmitter, and the beam would have to somehow magically focus itself onto a much smaller area before it would be a problem.

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    That's clearly the solar ray weapon from Gundam, used by zeon and the titans.

• In Another Step Farther Out [amazon.com] the late Jerry Pournelle talks about this. Like many such grand plans it depends on a heavy lift vehicle to get materials into orbit. Pournelle assumed that only governments could fund the expense and they'd grown bored of such things.

  Hello Starship.

  I think that we'd still be better off getting serious about nuclear power but once Starship is debugged it could be done.

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    You could make it relatively light weight. Make the solar panels flexible and kept taught by centripetal force. Or in other words, the satellite should be a heliogyro with the solar panels as its blades.

• If you want electrical power at good value, nuclear is the way to go.

  If you want an Archimedes Death Ray in space, this is a good start.

• China did this in, I think, 2019. NZ's Emrod did 2kW a couple of years back. One of the purposes of China's Tiangong is to test it from orbit. So great technology, great idea, somewhat overstated in the cutting edge department.

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    Typical China. You offer free energy and they complain.

• • Nuclear?

    By that logic we should also keep all that nuclear energy trapped inside those atoms where it belongs.

• I think this ends with burned out swaths of land when the beam gets misaligned
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• A space to ground power beam is basically a Death Ray by another name. Nuclear countries need to make it clear that deployment of a death ray will immediately be met with the nuking of Tokyo and this time the Imperial Palace wont be spared.

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    The comment above sounds like it's trying to be funny; but actually these would be the ultimate WMD. At 23,000 miles arrays of space based solar panels that beam back to earth with microwaves or lasers would be far worse that nuclear weapons. At least with ballistic missiles, you get a 5-20 minute warning and might be able to shoot it down. With these things, you could redirect the beam in maybe seconds or less depending on the technology and satelites beaming to Japan could strike much of Asia or the w

• The one person on Earth that should love space based solar is Elon Musk. Mr. Musk runs a company selling solar panels, and another company selling rockets. Both companies need customers to prove their technologies in order to be viable long term, therefore getting more customers. It is proving this long term viability of his rockets is why Musk got in the business of internet by low Earth orbit satellites. It is not the only reason but it certainly didn't hurt that he could use his own satellites as pay

• Dr Evil was such a visionary!
  He should have gone for astronauts instead of sharks.

• I'm willing to test this can I put a receiver on my roof?

• Let's focus more heat to the planets surface.

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    Can someone explain to those that make comments like the parent post how global warming works and how space based solar would help, not hurt? I'm not in the mood right now to go into it.

    Space based solar is a bad idea but not because it would focus more solar energy on the planet. It is a bad idea because the energy needed to launch everything into orbit is not likely to be paid back by the solar energy it collects and converts to useful energy. Even if we could improve the efficiency of the various step