back to article Enormous orbiting solar raygun power plants touted

Many years ago, in Galaxy magazine, Jerry Pournelle devoted his A Step Farther Out column to describing how satellites could be used to harvest solar energy on a scale impossible underneath Earth’s atmosphere. The idea never really went away, but it’s been mostly out of the spotlight. Now, Reuters is reporting a study by the …


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  1. Destroy All Monsters Silver badge

    I support this!

    But wasn't there a story by Asimov about a robot who went religious nutcase while in control of such a station, with everyone fearing that it/he/she may no longer be able to align the beam during solar disturbances, thus possibly causing large-area fritzy-frutzy earthside?

    1. Anonymous Coward
      Anonymous Coward

      Ziwzih Ziwzih oo-oo-oo

      It was called The Prophet.

    2. Thecowking

      That was "I, robot", god that book was so much better than the awful film.

      1. Bernard M. Orwell

        Pedant Alert!

        Isaac Asimov never wrote a story called "I, Robot".

        The book with the same title is a collection of short stories by Asimov which he originally intended to be called something entirely different, but was over-ruled by his publisher. None of the stories in the collection are called "I, Robot", although the "Three Laws of Robotics" do feature heavily throughout.

        The publisher obtained the title for the collection from another writer entirely (Eando Binder), who HAD written a (pretty bad) story called "I, Robot".

        The film bears no resemblance whatsoever to either Binder or Asimovs work.

        The story in which a robot "gets religion" is, I think, part of the Caves of Steel series which partly inspired the film.

    3. Anonymous John


      "Reason", one of a series featuring Powell and Donovan.

    4. Anonymous Coward
      Anonymous Coward


      There was, pretty sure it was iRobot, not to be confusd with the film about a man and his love affair with his shoes.

    5. Voland's right hand Silver badge

      The robot is the least of your problems

      The whole thing is one HUGE tangle of problems.

      Unless the solar batteries are positioned on top of something really really really heavy like let's say the moon they will be pushed by the solar wind out of their orbital positions. In addition to that all the "easy" positions in stationary orbit are already occupied so there will be some very entertaining logistics in terms of jumping from one receiving station to another and doing something with the surplus energy while the jump takes place (OK, that can be solved by multiple antennas but this means more weight, complexity, etc). Add to that that the energy beam will ionize the atmosphere and generate enough ozone and nitrous oxides to kill anyone for miles downwind...

      Why do I suddenly think that nuclear is such a good idea...

      1. BristolBachelor Gold badge

        The plan I saw had the beam hitting the earth with about 1kW/M², which is about the same as the power from the sun (in countries other than the UK where it is cloudy instead). The advantage over pure solar power on the ground was 24hour power, except for 70 minutes eclipses during the equinoxes, and better efficiency of the beam receiving equipment.

        The orbital slots were on the GEO belt. The gaps between sats up there is still big enough that we could fit a few of these in there. Plus it hasn't been said anywhere, but taking a miserly 4-16kW of the juice to run a few bent-pipe TV relays won't really hurt the power generation of the satellite. In fact, selling payload space might help pay for the things.

      2. Anonymous Coward
        Anonymous Coward

        >"they will be pushed by the solar wind out of their orbital positions"

        Well, that's a big problem. If only this orbital power station had... I dunno... some source of power, that it could use to drive engines to maintain its orbit with?

        1. Ignazio

          Energy yes

          Reaction mass not so much. Unless the probably frequent maintenance visits also provide something to be spat out of said engines, or a reactionless drive is also invented. In which case I'm gonna get myself one of those first!

      3. hplasm


        just how 'heavy' is the moon, then-?

        1. Paul_Murphy

          About 1/6th the weight it would be on Earth - why do you ask?


      4. Anonymous Coward
        Anonymous Coward

        All the technical problems are soluable at a cost...

        Gyros could be used to stabilse the Position in space.

        Geostationary slots are available and if not then something will get bumped to make way for them.

        I understood, but will be corrected, that the solar energy energy flux was 10kW/M2. this turns into about 200W at the surface at the equator with the losses being absorbed/re-emitted.

        The biggest issue is that such a device would be considered to be a space based weapon and would need to be controlled by one of the responsible superpowers wish space access - now who could that be......

        Wait for the energy prices to rise and no other options and we might consider this as a solution if we are not back in the stone age... Or we all become a bit more mature about this sort of technology?

        1. Alexander 3

          A few corrections

          Gyros can't, strictly speaking, position you in space; all they can do is control your attitude. Which is also critically important.

          You don't need to put a solar power station in geostationary. You would almost certainly put it in a MEO orbit. Not much atmospheric drag, lots of space, and little shadowing from Earth.

          Solar flux above the atmosphere is about 1.3kW/m^2

          You could quite easily show that such a space facility is not a weapon as the design would have to be considerably different. Plus they would be fragile, vulnerable targets if used as weapons. Nukes are far cheaper, easier and destructive...!

          I'm a big fan of solar power in space, but the economics demand a much cheaper launch mechanism. Roll on the Skylon!

        2. fch

          Since you ask to be corrected ...

          ... just use the omniscient garbage pile that is Google to find out about what's called the "solar constant". No, I'm not going to gtfy.

      5. Ru

        Re: "The whole thing is one HUGE tangle of problems"

        Your understanding of engineering and physics is atrocious.,

        I'll deal with your two most obvious errors.

        1. Station keeping will be nice and easy; just fit a brace of VASIMRs. There'll be more than enough juice to go round. You significantly overestimate the strength of the solar wind within Earth's magnetosphere too.

        2. Any beam that is ionising the atmosphere is wasting a colossal portion of its energy... so much, in fact, that it could not possibly be economic. The transmission beams will be tuned for minimal absorbtion by the atmosphere.

        I wonder what the cause of Pathological Internet Omniscience is. You clearly know nothing about the issues, yet rant as if you're informed.

      6. Ignazio

        Surplus energy...

        ... point the massive microwave cannon sideways and blast space debris out of the way. One stone, two birds.

  2. Kenno


    TBH I don't know why a giantic magnetic rail gun / catapult into space to shoot things up there hasnt been built yet. It would make such things (after the initial and horrendous building costs of the darned catapult) somewhat cheaper than sticking things into orbit now,

    Anyway such stories are common place in Sci FI, in gundam 0083 they had the Solar System II mirror array. This was used in an attempt to stop a colony drop though.

    1. Mike Moyle

      Rail guns?

      | "TBH I don't know why a giantic magnetic rail gun / catapult

      | into space to shoot things up there hasnt been built yet."

      To get into (and stay in) LEO, an object needs to be traveling at about 17,500 mph when it reaches its orbital slot.

      A rocket gets there by starting off traveling slowly down where the air resistance (and hence friction) is heaviest and accelerates as it rises into less dense/less compressible/less friction-inducing atmosphere.

      On the other hand, atmospheric friction and compression is used when decelerating out of orbit. This generates thousands of degrees of heat which needs to be dissipated/shielded against.

      Now take your rail gun. Assuming as a starting point that it is long enough -- some number of miles maybe* -- that the acceleration to escape velocity doesn't pancake every structure in your launch vehicle and payload, there is still the issue that being at the bottom of a gravity well requires that your projectile be going at well OVER orbital speed when it leaves the muzzle.** Otherwise,just as with a thrown rock, gravity will start slowing it down as soon as the driving force is off. If it doesn't reach orbital height at orbital velocity -- just like that rock -- back to earth it falls.

      So your railgun launcher has to -- slowly enough not to destroy the projectile -- accelerate it to something in the 20,000 mph range... at sea level... in order to still be at orbital velocity when it finally reaches its intended altitude... And once fired into flight, the projectile has to be sufficiently heat-resistant that it isn't instantly immolated by friction/compression-heated atmospheric values above anything that humankind has ever built. (Bear in mind that -- while, granted, its thermal protection had been compromised -- the temperatures and stresses that destroyed the shuttle Columbia happened when it was decelerating from the arbitrary "edge" of the atmosphere at 75 miles above sea level down to final breakup at about 40 miles up.)

      ...And you want to shoot your payload out of a cannon at HIGHER speeds than the Columbia was traveling, in atmosphere that is DENSER by a couple of orders of magnitude than she was traveling through, and hope to get it to orbit intact...?

      Good luck with that.

      A long-enough catapult might POSSIBLY be useful for accelerating something akin to a SCRAMjet to operational speed, which could then accelerate through much of the atmosphere before handing off to a rocket engine for orbital insertion, but a catapult to orbit setup without any other motive force...? SO not happening. And I see no way that a catapult/scramjet/rocket combination isn't going to be MORE complex and expensive than what we have now,

      No, I'm afraid that (absent any completely new science like antigravity) until we get the first beanstalk built, rockets are pretty much going to be the only way into orbit.


      * The difficulty of building a miles-long, precision-engineered railgun in an utterly straight line tangent to your starting point on the surface of the earth (You can't just put a ski-jump at the end if you're launching something at Mach 27 or so) is left as an exercise for the reader.

      ** Ditto the effects of a Mach 27 sonic boom on surrounding organisms and structures (including your miles-long, precision-engineered etc. etc.).

      1. Veldan

        Nice post


        There are just a few extra ideas around the subject which I've heard for helping to make it slightly more feasible.

        Namely building it up the side of a mountain, the bigger the better. Though land rights (Everest would be lovely) will be an issue and there is still a large technical challenge there. However it would be a lot easier than trying to build a 7Km tall building...

        The launcher itself of course would have to be vacuum sealed so as to not destroy itself with super sonic speeds and the like. However as for the exit from the tunnel I have heard some people talk about the possibility of either firing a sacrificial leading shot to help disperse the air opening up a vacuum ahead of the tunnel for the actual payload or accelerating the air to nearly the same speed as the payload (massive leaf blower :p) to try and cushion its launch.

        These are still far from perfect and well beyond out technology but the idea isn't without merit. Perhaps for lugging very large solid masses (ores, minerals, etc) which are to be later picked up by another conventional rocket powered vessel.

        (Icon? Mostly likely result from that hydrogen/uranium shipment they were sending to the moon...)

        1. Nigel 11

          Rail launch

          I've always wondered why (outside of the movies) no consideration seems to have been given to a launch where the first stage of aceleration uses external electric power to drive the rocket up a ramp. I'd have thought that there are considerable advantages to firing the rocket when it's already travelling at (say) 300mph along a ramp up the side of a mountain.

          1. BristolBachelor Gold badge

            The Russian Depnr rockets are ejected out of an underground silo using steam and then the rocket motor is ignited once it's above ground (I kid you not!). You are not allowed to know too much about this, and not even look in the direction of the silo when you are there, but this website from one of the suppliers shows it nicely:


            Although maybe this isn't exactly what you meant :)

        2. Isendel Steel

          7km Building

          Phineas & Ferb did it in a morning....

      2. Neil McDowell


        Could you build it on the side of a very high mountain?

      3. Ignazio
        Thumb Up

        Beanstalk +1

        Meantime, what about shooting rockets from very high altitude balloons? (idea shamelessly pilfered from Red star, Winter orbit by Gibson & Sterling)

  3. Ron 6
    Thumb Up

    What goes around comes around?

    NASA did studies on this back in the late 60's or early 70's. The main problem is, of course, the Green folks.

    1. Anonymous Coward
      Anonymous Coward

      Aren't they always when progress is involved?

    2. Havin_it

      Green Folks

      They're just pissed that Capt. Kirk kept loving and leaving them :S

  4. Pete the not so great
    Thumb Up

    just deliver it in

    milk bottles

  5. Entropiated

    What about the poles?

    Instead of trying to hit a spot on the Earth rotating at over a thousand miles-per-hour with a high-energy beam of microwaves, would it be possible to place the collector (s) at the poles so that the target doesn't move so much? From the poles we could build a distribution grid to carry the power down to the lower latitudes. Less of a chance of zapping someone by mistake that way.

    1. Tomato42

      Aiming high power microwave at ice... Ask Belgians how they feel about this idea.

    2. Chemist

      Re :"What about the poles? "

      The apparent rotation of the earth would be zero as the satellite is intended for geostationary orbit.

  6. Anonymous Coward
    Anonymous Coward

    Didn't the Xindi try this already and it ended badly for Florida, or am I getting Star Trek and reality mixed up again?

    Seriously though, this could end badly in so many ways if the wrong people were in control. You wouldn't want the downlinks anywhere near populated areas, air routes, bird migration routes, etc. Presumably as well, the downlink stations would need to be in the equatorial region which doesn't leave too many bits of land in stable countries to choose from.

    1. Joe Zeff
      Big Brother

      You can put the downlinks almost anywhere you want

      "Presumably as well, the downlink stations would need to be in the equatorial region which doesn't leave too many bits of land in stable countries to choose from."

      No, you don't have to put them near the equator, it's just that you get the most concentrated beam that way because the farther away from the equator you get, the more the beam spreads, just like sunlight.

      And, there's a real nice advantage to this that nobody's mentioned: once you get a country dependant on your beamed electricity, all you have to do is shut it off if they do anything you don't like, and there's not one damned thing they can do about it. Kind of like OPEC, only more so.

  7. Ron Luther

    Not to mention ...

    ... being able to recalibrate to destroy all of those those nasty incoming comets!

  8. Thomas Gray

    I've read enough Eagle comics to know where this is going...

    The Tower King

  9. Clive Summerfield

    Pournelle had plenty of "good" ideas back in the day, and was worth listening to if you could handle the rather hectoring style and right wing ranting that sometimes accompanied his utterances. Wasn't he part of the "Rods from the Gods" brigade?

    1. Destroy All Monsters Silver badge

      Yes, there was a chapter called the "The Jayhawk War" or something in "Footfall" where aliens rod a whole tank division from orbit.

      In five minutes it was all over.

      I have never heard anyone explain how one actually *deorbits* those rods without huge boosters and keeps them on target for the pretty chaotic ride down. One cannot just drop them.

      A the joys of americocentric warjerking.

      1. Stephen 10

        Off the top of my head

        a rail-gun (see Moon is a Harsh Mistress for lunar based prior art).

        Of course the proper way to build this stuff is with a suitable rock boosted in from the asteroid belt. Would take years but it's entirely do-able. Requires real long term investment though, so it'll be a long time before we see it.

  10. moth
    Terminator is the story you are thinking of. There is also a spooky Delia Derbyshire track from the BBC tv adaptation that is worth checking out:

  11. Anonymous Coward
    Anonymous Coward


    Good idea, except for the Microwave oops! disaster scenario.

    1. Ru

      Yay sim city

      The risks of frazzling the target site are smaller than you might expect. There's probably an optimum surface power density value that depends on how efficienr your microwave photovoltaics are, and how big a receiver array you can build. You certainly don't want to be transmitting power on a microwave frequency easily absorbed by water, which would of course by the optimum frazzling mechanism.

      Being irradiated by a strong RF emitter isn't going to be very good for anything, but these aren't going to be orbital death beams.

      1. Olafthemighty

        >"but these aren't going to be orbital death beams"

        Orbital death beams? What orbital death beams? Nobody mentioned orbital death beams. What aren't you telling us?

        <-- Dooomed, I tell ye.

        1. Ignazio

          space sharks would need those wouldn't they? Dibs on the space shark idea btw.

  12. Anonymous Coward
    Anonymous Coward

    Someone explain why you would want to spend (tens of) billions of pounds lifting heavy solar panels into orbit, along with all the consquent problems with maintenance, control, power transmission, array degradation, non-negligible chance of catastrophic mission failure, when you could just build twice as many dirt cheap panels on the ground to make up for the fact that you get 12 hours of sun rather than 24? Unless 'much more sun' is many multiple orders of magnitude greater, an admittely untrained idiot like me cannot see the economic case as to why solar panels in orbit (at costs thousands of times higher than building terrestrial arrays) are even being considered.

    1. JimC

      Why in orbit?

      Because there's no pesky atmosphere to get in the way of the solar energy.

    2. catprog

      Try 5-6 times as much energy from space solar(generally you only get 5 peak hours of sun). But costs for space solar are a lot more then 5-6 times then terrestrial solar.

      1. Tomato42

        Because earth based solar array can produce electricity for about 10% of time averaged over a year.

        Add the energy stopped by atmosphere and you have a system that is at least 100 times as effective.

        1. Anonymous Coward
          Anonymous Coward

          Someone actually gave you a thumbs up for this? Utter bullshit. The equator gets 12 hours of sunlight a day (not 2.4, as your 10% figure estimates) and If the 'energy stopped by the atmosphere' was indeed 90% of the suns total power, then where does that energy go? As heat? Since we still -have- an atmosphere, I can only surmise that 90% absorption figure is bullshit too. And even if it wasn't, and an orbital array was actually 100x more efficient than a land based one.. then you're still only another order of magnitude or two away from it being as cost effective as a ground based one. Oh wait... except you have to beam that energy back to earth, through that incredibly opaque atmosphere that inexplicably causes 90% transmission losses... bwuahhaha....

          At best a solar panel in orbit is going to give 5 times the power of a land based one. Not 100 times. And it'll cost thousands of times more to get it up there. So I'll let you do the simple maths (1000 >>> 5)

          1. Anonymous Coward
            Anonymous Coward

            It doesn't seem to add up

            As above. The Desertec project to produce 15% of Europe's energy from solar power in the Sahara is much less challenging and would produce cheaper power more quickly.


  13. Kinetic

    "space junk permitting" - Small caveat really when you're providing a 1km wide target.... depends on the orbit and angle I guess.

    I'm sure the military will be thrilled to get their new super-weapon built for them - sorry, I mean perfectly safe microwave beaming system. Yup no dangers to worry about at all, no sir, not here.

    [ION Cannon charged]

    Now where were those pesky NOD terrorists.

    1. JanMeijer

      my point exactly

      having something up there with the capability to create instant 1km diameter cropcircles anywhere sounds not unequal to having nucleair warheads up there. Stuff like "large things that are easily turned into serious weapons" up there is nice when we've solved this little detail of warring nation states.

      Who would be in control of said station? If it's not me (all hail your future dictator) I won't trust it ;)

    2. Ken Hagan Gold badge

      Re: new super-weapon

      Yes, indeedy. Start building one of those and I'd have thought that every other space-faring nation would regard it as their DUTY (not just their right, although presumably references would be made to UN charter articles and treaties on space weaponry) to blast it to pieces before it could beam down anything more powerful than a GPS signal.

      This idea is a non-starter.

    3. Tomato42

      Unfortunately we're coming to an age where each and every energy production and storage system has tremendous amounts of energy stored just in regular operation.

      The same is with space ships: any propulsion systems able to move people fast from planet to planet has enough energy to make big holes in them: you get kinetic energy equivalent to antimatter annihilation of same mass at only a bit over 0.7c...

      1. Chemist


        I make it ~0.9c but I take your point. It does point out the difficulty ( I mean impossibilty ) of fuelling any type of ship intended for such speeds. Any fuel mass just becomes more mass to accelerate .... recurses !

  14. HMB
    Black Helicopters

    Solar Radiation

    Solar Radiation. NOT SAFE IN ANY AMOUNT.

    The sun should be banned.

    (UV from solar radiation is ionizing, just like gamma rays, hence sun - skin cancer link)

  15. Kinetic

    Double the're kidding me?

    From the linked article:

    "Jeff Peacock, who heads satellite-builder Boeing Co's (BA.N) ground-based solar cell product line, said in theory it could double the amount of solar power collected, compared with the Earth-bound technology equivalent."

    Yes folks we could double the solar collected...for only a thousand times the cost, and a crap load of inconvenience and danger*! Bargain!

    This is sounding more and more like a thinly veiled space weapon - but I'd expect them to do a much better camouflage job than this....or maybe that's what we'd be expecting...errr.....where's my tinfoil hat?

    *(Yes I have no idea how much a 2km solar array would cost on earth but it's got to be a hell of a lot cheaper than constructing and maintaining a 1km one in orbit and then beaming the power safely back to ground stations on earth. There has to be more to this... it sounds insane.)

  16. Medium Dave

    Not this s--t again...

    The problem isn't the death-rays-from-space, or the panel-turning-into-a-solar-sail: It's the insane cost of getting something into orbit and assembled. We already have large solar panels in space - They're on the ISS, and if you look at STS-115 it works out at half a billion USD for 70Kw.

    It would be cheaper to get 1,400 Chinese people running on treadmills for 40 USD per day. Or suck down the FUD and build some nuclear reactors, already.

    1. Tomato42
      Thumb Up

      +1 for nuclear, no matter what the Ecomentalists say, its the safest method of energy production we know that actually works.

      1. Medium Dave

        I generally count myself as an ecomentalist...

        ...but, one who understands physics and chemistry - a sad minority. If we could get the f---tards at greenpeace to understand that seawater contains uranium and rainwater contains tritium, we'd solve our energy problems by next Thursday.


    2. TRT Silver badge


      convert human beings into biochemical batteries which you could array in huge nursery stacks, whilst keeping their conscious mind occupied by means of a computer generated artificial reality.

      Actually sounds like it would make rather a good film and a couple of shit sequels.

  17. Adam White

    This is a silly idea

    What we really need are GELFs with dyanmo organs.

  18. Herbert Meyer

    citing Heinlein, Asimov already cited.

    Heinlein thought low orbit was the best place for fission power plants. But then "Blowups Happen".

  19. heyrick Silver badge

    Gee, what could POSSIBLY go wrong?

    At least, when it does, it'll be a crowning moment of epic.

  20. Error Message Silver badge

    Station Keeping

    I'd want to see the technical aspects for keeping it in orbit. The residual drag on a 1km square object in LEO (Low Earth Orbit) would be huge.

    1. Chemist

      @Error Message

      It's intended for geostationary - in any case how else would it be able to point at a receiver array ?

  21. johnwerneken

    Excellent idea...then and still

    When will people realize it is raining in resources out there and all we need to do is to show up with a bowl.

  22. BeagleSeven

    Gerard K. O'Neill

    Gerard K. O'Neill wrote a book in 1974 titled "The High Frontier" (Human Colonies In Space),

    about this very idea. It seems to have been totally forgotten. I have in a Corgi book (0 552 10822 7) - published in1978.

    1. Paul_Murphy

      I also have this book.

      Covers so much ground.

      It's probably one of the reasons I'm so bitter, warped and twisted - the flying car/ space hotel future I was supposed to be growing up into is looking further away than ever.

      It makes me sad.


  23. Anonymous Coward
    Anonymous Coward

    They had something like that in Command & Conquer

    Only you used it to blow up the whitehouse.

  24. Anonymous Coward
    Anonymous Coward

    I'd like to congratulate all the naysayers who slated this plan for stuff that aren't actually problems because they couldn't be bothered to learn anything about it.

    Its not in LEO, its in GEO, which is easy to station keep at, and had little junk.

    Beam spread means the width of the beam at ground level is on the order of a kilometer across and diffuse enough to be no danger to health even if its on you continuously all day every day (its under US workplace safety limits for continuous exposure). Using it as a weapon isn't just difficult, its totally impossible (you can still threaten to turn it off and cut someone's power, but that's an issue with many fuel sources, both green - eg. solar sahara- and fossil - eg. russian gas).

    In any case, fail safe systems to turn it off if its pointing at the wrong place are pretty easy to make foolproof (e.g. put a reflector on the ground station, and a hardware link to a detector on the satellite - beam veers off target, reflector on the ground no longer has anything to reflect, satellite's detector is no longer illuminated, power is cut off).

    Power output per panel is huge - max power of about 1.5 times the best you can get on land solar, but it gets that on all solar arrays, 24 hours a day, 362 days a year. Land-based solar is at maximum for a few minutes at noon at the equator, and averages way lower than that for a whole day, plus being completely off at night, and then only if it isn't cloudy.

    The key thing is that this requires no new tech. We've got the solar panels, the power transmission has been tested, we can put stuff in space and keep it there. All the parts exist and just need to be put together. Unlike, for example, fusion, we know how to do this.

    There are 2 main problems. The small one is space, GEO requires being above the equator and its already full of communication satellites, and interference is going to be an issue.

    The big problem is cost per watt, and that absolutely requires cheap access to space. NASA will never be able to do it, SpaceX might. Someone really ought to look into full scale laser launch systems too, they have a lot of potential. But any commercial venture has got to deal with this or its a complete non-starter.

    1. Malmesbury


      Basic physics 101 -

      You can't build an orbital death ray with microwaves, unless you used a antenna of insane (100s of kms) dimensions. Easier to build a small antenna and allow bean spread. Just cover x amount of farm land with chicken wire on poles. Land is cheap in this context

      The best scheme is to use a phased array antenna for transmission which is locked onto a pilot transmitter on the ground. If the orbital antenna looses lock, all focusing would be locked and the power per square whatsit would go down from less-than-sunlight to I-need-a-better-detector-to -detec anything.

      It is useless as a weapon - "Do as we say or we will turn our beam of microwaves on you. At an intensity that is classified as safe for the workplace by 'elf and safety".

  25. Simon Neill

    Sounds good...sort of.

    Would such an array EVER pay for itself? I mean, solar arrays down on earth are expensive enough. Add in the costs of getting the things up there...

    Ok, so its more efficient up there, there is less maintenance involved - no birds to shit on the panels and all, but does that difference really cover launching into space? Launching 1kg 100km straight up (roughly edge of atmosphere) requires mgh J of energy = 1 * 9.8 * 100,000.

    = 980,000kJ assuming 100% efficiency.

    assuming about 20% efficiency this array has to generate approximately 2kWh per kg it weighs just to cover the launch energy, never mind production of the array and the ground facilities. I'm also guessing 1kWh of rocket fuel costs more than 1kWh of electricity.

    1. Dave Bell

      The energy cost of a launch to GEO is trivial. This system will only need to run for a few hours to cover that.

      But there are people who will see the figures, with all those zeroes, and scream and point about greenhouse gas production.

      Similarly, some will make a fuss about the system pumping more energy into an overheating planet. Well, the Earth is pretty big, and the extra surface area is a tiny increase. Figure in the reduction in greenhouse gases: just make sure you use the "right" model for the effects.

      In the end, this depends on being able to do the construction work, and, wonderful though the ISS is, this is something that is going to depend on robots. Not the mechanical men of so much sci-fi, but remotely operated machines, well beyond the automatic docking of a supply ship to the ISS.

      NASA spent huge amounts on spacesuits to get a man's hands on the job. They might have made a better return on a mechanical hand, and the control and feedback mechanisms to let a human hand control it. Even if the astronaut had to be in the Shuttle (communications lag), did he really need that awkward personal spaceship?

      1. Malmesbury

        The energy isn't the problem

        To raise the Earths temperature just by adding heat would take an insane extra amount of power - think multiply world energy expenditure by 100x to see noticeable effects. This is because the heat radiates away. You'd get some heat islands (see modern cities).....

        Green house gases are about accidently installing extra double glazing and keeping unwanted heat in. Not the heat itself.....

  26. Matware

    I wonder how much it would cost to....

    Create an equatorial solar array (nominally at sea level) 24 hours of power, no need to ship it into space.

    My beer coast calcs say you'd be able to create a 1 panel wide array around the earth for between $12 and $20 billion. This would produce ~1GW continuously, with the added advantage of being on the fcuking ground. This assumes retail prices for panels. And is an horrendous wast of cash.

    To launch said panels, using say, a non-existent space shuttle would cost ~$1700 billion (not including the panels, not including cost of launch vehicles) and take decades. This also adds an embedded energy of ~66Mj / panel to each panel.

    This is so much BS designed to put off solving today's problems until tomorrow (like the hydrogen economy, fusion etc). We need to be building nuke plants and R&Ding LFTR reactors, fusion and industrial scale solar.

  27. NomNomNom

    I tried this in sim city 2000 and it didn't end well

  28. Anonymous Coward
    Anonymous Coward

    solar in orbit

    I live in Dubai, and it is sunny 360 days per year. I mean no clouds, bright sunshine - virtually every day. The place is surrounded by desert with nothing in it. Look at a map of the earth - a goodly portion of the place is sunny everyday and completely empty of people and anything else.

    Sure you can pay 30,000 bucks per kilo to put some solar satellite that cost millions of dollars to construct into orbit.

    Or... you could just put 10 or even 20 of the same solar panels on the back of a truck and take them into the desert. The power output will be the same. The cost... a tiny fraction of your orbiting solar station.

    Maintenance? Hubble-style servicing mission or man in a jeep with a spanner... tell me, which is going to cost millions and which is going to cost 20 bucks an hour or 25 on weekends.

    This whole space power thing is so laughable ridiculous from an economic point of view that I cannot believe people are even discussing it.

    1. SteveK

      The trouble is that the big, empty chunks of desert are nowhere near where people want the power. Americans probably don't want to be dependant on the people who sell them oil for electricity either, and it is harder to ship.

      That said, I came up with the idea a couple of years ago of building big solar arrays in the desert, then converting oil tankers into huge batteries that you charge up at the solar array, and then take and dock in some far off country and plug into the grid... sure there are all sorts of issues surrounding this giant battery idea, most of which involve release of nasty chemicals and so on if one sank...

      Another idea - put a huge array on the moon and beam it back to Earth in a beam wide enough that encompasses most of the planet, at low enough power that won't cause any harm, and pay for it by selling us all some sort of induction charging devices that suck 'free' power out of the air. Obviously only produces power when the moon is up in your region, and is subject to moon phase (best to have two arrays, at left and right sides of the moon so would only produce nothing close to new moon), but it would complement existing generation systems.

      I never said these were good ideas...


  29. Tim Worstal

    The microwave transmission

    This has also been tested. Between two Hawaian islands: fortunately just about the thickness of the atmosphere but horizontal like.

    Works just fine.

    As above, the technology is all there, all we need is low price to GEO and we can do it.

  30. Matware

    Sorry to be a hater again but...

    Its very rare to find a successful business or engineering project that relies on lots of shiny new moving parts.

    If I was a bank manager and somebody came to me and said

    "Hi, as you know our company has got all this experience is building 2-10 km scale space structures, and this business partner of ours can lob a payloads into geo for for $1000/ton.

    We noticed that company X has just released their new 35% efficient new space ready solar film for $15/m2 meter. Everybody knows how cheap high efficiency microwave tranciever sets are now days.

    So all we need is a GW scale microwave beam collimator and we have found a couple plucky young grads who seem to have it nailed! So, for $500,000 million we can build a GW solar plant and turn those free watts in space into $0.05/kwh.

    EBIT is about 12% and given the current climate we expect to pay it off in 15years. You in?"

    If anybody wants to tell me which of the above moving parts actually exist now, or will exist in the next 10 years I'll invest. On the other hand, any of those things actually existing now or in the next 10 years would probably make space based solar power a wast of money as each one of them is a complete game changer.

  31. LG

    Engery Density

    Why stop at earth orbit? Move these things closer to the sun, collect a lot more energy... take advantage of r^2.

  32. Anonymous Coward
    Anonymous Coward

    Move in for a better view.

    Move them closer to the sun, collect more energy. 1/100th the distance, 10,000x the energy.

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