$21 Billion Orbiting Solar Array will Beam Electricity to Earth

That's what I like to see: people with vision, ambition and courage. Crazy as this idea may appear today, how stupid will today's critics appear when they accomplish this, (or something similar as a spin off project).

If they forge a better working relationahip with China in the coming decade, solar power may become available at commercially realistic values to all of us - finally.

I am tired of the limiting factor being monetary value. We as the human race are capable of such extraordinary things that it's practically blasphemous that we allow such trivial matters to hinder progress in science.

Umm...I agree with Ray and all. But..Aren't there rocks in space? And giant floating balls of ice? How do you prevent a crash-collision with those? Much less take into account solar storms, micro-meteorites, dust in space, etc. and still make this viable?

I am tired of the limiting factor being monetary value. We as the human race are capable of such extraordinary things that it's practically blasphemous that we allow such trivial matters to hinder progress in science.

I don't think we're "hindering progress" so much as leveraging our limited resources in the best way we know how. Nobody anywhere can justify $1 Billion per megawatt. It would probably cost less to have a human crank a turbine by hand... this is a big gamble. Even if they get the cost way, way down, how will they fend off the critics that will claim this can be used as a space-based superweapon? Kudo's to Japan for talking the talk, it'll be fun to watch them try to walk the walk

If even cell phones are said to cause health problems, what is going to happen when they beam down that much radiation into their collector facility?

I am tired of the limiting factor being monetary value.

This is evil and stupid; but 1000 characters barely allows me to scratch the surface.

Money is not the limiting factor; money is just an abstraction. The market generates prices for things incorporating the expectations of all market players; this allows efficient use of scarce resources. Without money and markets you have a knowledge problem(even Lenin recognized this when he suggested keeping one small country capitalist to see what prices looked like). Ignoring prices is squandering resources.

What you're suggesting is that prices allow people to spot bad ideas and avoid them; the only way to circumvent this rational behaviour to further your pet projects is to have government expropriate money through taxes and squander the stolen loot on your pet project(e.g. see corn ethanol or the bridge to nowhere for real world examples of this). This is evil.

If YOU want to squander YOUR resources, more power to ya.

If even cell phones are said to cause health problems[...]

50 years and thousands of studies on everything from radar, microwave ovens, high power radio towers, powerlines, car phones, cell phones, WiFi etc. say otherwise. All it does is dielectric heating; stay out of fields intense enough to overwhelm the self-regulating cooling mechanisms of blood circulation and sweating and you'll be fine.

what is going to happen when they beam down that much radiation into their collector facility?

The collector is tens of square kilometers at 2.4 GHz because of diffraction; it's going to be a lot less intense than sun-light.

Build the space elevator first, then we'll have a physical connection to a power generator we can stick out in space.

I largely agree with your statement about the purpose of money Soylent. It is merely a way of allocating non-infinite resources, and nothing more.

However, I would disagree with your implied assertion that private investment is the only type of investment that is worthwhile. Private investment is by its very nature short-term, and cannot be used to fund long-term projects.

IE, no private corporation will ever fund research into FTL, because commercialization of that research is too far into the future to have a decent return on investment (if it proves to be possible at all). But because no corporation will fund the pre-commercialization base research, that research will never get done, so we'll never get to the point where commercialization is possible. It's a catch-22 situation. That's the reason why government funded *basic* research should exist: to fill that unfortunate gap in corporate and private research that would otherwise stifle the economy.

A space fountain should be on the list before or during SPSS and elevator construction. Also i'd rather see nuclear resonance technologies applied than inefficient panellings, maybe some xenon-tmae nematic liquid crystal capacitor hybrids or something.

The key to reducing costs is to manufacture the solar panels on the Moon and use something like a electric rail gun to launch them from there. The issue then become how many SPS's manufactured this way (and other ways to exploit the Moon) will be necessary to off-set the costs of building the infrastructure required to manufacture and launch panels from the Moon?

The key to reducing costs is to manufacture the solar panels on the Moon and use something like a electric rail gun to launch them from there.

Really??? Can you expand on how you think this would make it more economical?

I am tired of the limiting factor being monetary value. We as the human race are capable of such extraordinary things that it's practically blasphemous that we allow such trivial matters to hinder progress in science.

You're right, did anyone ever think that having a solar array in place would be a huge advantage by the time it is built? Once solar panels are more efficient the procedures to make this cost friendly will be like changing the oil instead of building a new car. What is also disappointing is that there is not enough "money" to fund the research on materials necessary to stabilize a fusion reactor plant.

well, even though this project is destined to fail, at least the japanese are finding ways to spend their dollar reserves. let's only hope this project is being paid for with their massive dollar reserves and not in yen. how funny would it be if the engineeers in japan getting paid for this project didnt' get their salaries in yen. ha!

it's a better idea than dumping the dollar on the open market and crashing the american empire to pieces.

I think we will be able to ingest trace nanometal targets and bask in the beam of this thing, and the heated particles will kill cancer cells. This will be the Lourdes of the 21st century.

evil and stupid

You Luddites better hold your breath because the next 20 years are going to be breathtaking.

well, even though this project is destined to fail, at least the japanese are finding ways to spend their dollar reserves.

You didnt see the one for California in the Related Stories box? --->

This is so silly. Japan has a great deal of unexploited geothermal energy potential that the $21 billion spend on geothermal projects could probably produce at least ten times as much electricity as this inane space-based scheme proposes.

You didnt see the one for California in the Related Stories box? --->

And in that article on the California project, they state: "According to Solaren, the system could generate 1.2 to 4.8 gigawatts of power at a price comparable to that of other renewable energy sources."

Do we have some super-secret method of creating the Orbiting Solar Array? Are the Japanese not nearly as intelligent as the rest of the world gives them credit for? Or is that company, Solaren, blatantly lying ("overestimating") the potential? I vote for the latter

There is an urgent situation on earth now; the greenhouse effect has been underestimated by half according to reliable scientists. The cost of a solar power satellite will build 20-30 solar thermal power plants. Its wasting precious time on money to build space based power-sats.

Space elevators are too far into the future, but a hypersonic "skyhook" would be doable with materials with twice the tensile strength of kevlar or spectra. The example I found in an article in a magazine 20 years ago was based on a cable orbiting with the lower end just outside the atmosphere at 5.4 km/s (just 5 km/s relative to the ground due to the rotation of the Earth). This would make SSTO launch vehicles realistic without the need for exotic new alloys.
(Personally, I think better drilling technologies will make geothermal energy the best rival to land-based solar energy)

unleash an age of free energy and extremely fast transportation

Sweet Jesus!! On a more pragmatic note; it occurs to me that japan and California are both long overdue for seriously destructive seismic events. CA's Clearlake geothermal installation sits on a very active location. Hotspots tend to be where one can expect large temblors to occur.

Solar satellites will continue to deliver power even if the ground facility is destroyed, and I assume the beam can be redirected to an emergency location, in the middle of a grid, instead of trying to reconnect to remote supply. This system may be FEMA-inspired idea.

Its not the production of energy, its the transmission of energy to the user that cost. Cant you people understand this.

Can you say oversized magnifying glass!! And we're the ants. What's gonna stop Japan or one of those controling companies to focus that beam over a city and cook everyone alive. Far better than a nuke, no radiation. There is more than enough power options to research here on earth - geothermal, fusion, magnetism, all could use that money to produce power for millions rather than only a measly 300 000. If it's more to do with space research, how about they design and build that cable based space elevator instead.

Space junk is a serious problem for space missions. Mark my words... space debris is gonna tear this thing apart.

Their money would be much better spent on other energy production methods such as geothermal and wave.

Here we go again
you cannot beam electricity anywhere electricity has to be conducted by a looped flow and return system. it could possible be changed into some sort of carrier but as electricity it would need a pair of cables from the orbiting device to a point on earth, which is practically impossible.

One point I think we're missing is the fact that solar energy is, for all intensive purposes, unlimited. The energy is being expended by the sun whether we capture and utilize it or not. Every second, more power is being released by the sun than we as a species have used in our entire history. What was the number, something like 800 billion megawatts?

you cannot beam electricity anywhere electricity

Tesla seemed to think otherwise if I'm not mistaken? Also what is an electron gun? Electrons flow from positive to negative as a 'beam' right? But thats not what this article is about.

solar energy is, for all intensive purposes, unlimited.

So, whats your point? Anything we build to capture and convert it does have a finite existance, costing money and resources both to create and repair/replace. This statement may not have anything to do with whatever point it is youre trying to make.

hi otto1923
someone suggested your argument in a response to a previous article. From my reading of his work tesla did not appreciate that the Earth also acts as a conductor. If you were to stand on a tiled bathroom floor without any insulation between your feet and the floor and touch a live source you would understand this in an instance. The projections through air that tesla performed used the ground as a return. What electrons do is not important. Electrical flow possibility is exactly what this article considers. As suggested the electricity could be converted to a microwave or laser then reconverted at ground but the losses in two conversions would outway the advantage of having the detector in space.

Thanks ant that makes sense

This is nothing more than their version of industrial stimulus project, aimed at directing taxpayer money to MHI and other corporations that despite being still blocked from exporting weapons, need to practice their rocket science. Like most Japanese government projects, it will consume vast amounts of money without producting uesful results

Hi all Dont Know if anyone is still reading this article posts but let me add a final warning:
As I previously said the energy created could be converted we assume to a laser or Microwave transmission. What either of these solutions would provide is a potential space weapon. Either of these could be used to threaten, blackmail or fry members of the human race. Imagine a terrorist group gaining control of such a device, a computer and transmitter is probably all it would take. We should NOT allow anyone to put devices with alternative potential into space. Please.

I'll note that you don't *have* to have a loop for electrical flow, that just makes things a lot simpler, easier, and more efficient. If you turn something into a plasma and then gather all the electrons from that plasma, you can do whatever you want with them (ie, fire them off into space as a Charged Particle Weapon). That would of course be an incredibly impractical way to transfer usable electricity around:P.

Hi Ant
We already have dedicated airborne and most likely space laser and microwave weapons specifically designed for the purpose. Maybe terrorists could grab control of these beams but I doubt it. If Japan makes one wrong move we zap them back with alacrity. What are you worried about? Ants and magnifying glasses pfffft?

Ther problem here is that by the time the panel system is ready to launch, solar technology will have left it in the dust. Articles here talk about solar paint and increasing efficiency by factors of 5 or 10 in a short time. This thing will be obsolete before it can be packed into a crate and launched.

Self-repairing nano panels are needed before this kind of space floater concept is really viable.

The solution to the energy issue is the solution to the number two killer, obesity. The government should issue out exercise bikes and stepper machines to every household and connect to the grid via low voltage trickle in-120 volt out parallel capacitors. People will loose weight while providing energy to the grid and cleaning the air. This will also reduce healthcare costs and food consumption which all utilize energy. The name of this program should be "ThinEnergy".

This solar R&D is for living and working in space. It has to be developed here and applied out there to refine and proof it. Certainly this will be obsolete by the time it comes on line, but what they learn from these programs can be incorporated as the tech matures. Consider that it may be easier to construct these stations here and sent to lunar orbit to supply bases on the surface; or to mars for example.

This is good news! The earth is getting ready to hatch!

Seems like it would be a lot more sensible, cost effective and far less risky to focus on making cheaper, more efficient solar panels and blanketing the rooftops of entire cities with them.

Quite weird idea to collect solar energy in space and transfer via microwave or laser to earth with the risk to burn people!

The most obvious solution is to build solar panels on top of roofs of each house, having a distributed solution with all the advantages that distributed solutions have, e.g. internet!

Why not just float up balloons with solar panels above the cloud cover and beam down the energy from there?

Why not just float up balloons with solar panels above the cloud cover and beam down the energy from there?
Alternatively the balloon could be tethered to the ground and the electricity could be conducted down the tethering wire.

Every one just needs to get ready for an energy war. The industrial revolution should never have happened. In just 100 years man has gone buck wild with energy. Putting solar panels in space is a mathematically a dump idea. First you have to deal with the cost of getting the pannels in space, then the fact you are collecting energy to transmit it will always produce a lower net energy and finally the micrometeorites will damage the lenses so that maximum sun focus is reduced. Just put them on the roof of the house and be satisfied. Sometimes I think that engineers create things that will keep them employed for the long term. Is this why cancer and diabetes still exist (acidic body and diet). Research is more profitable than the one time cure which is prevention. Let us prevent these off the wall ideas from being realized. We need the space elevator though to take the glory away from astronauts.

The inverse square law will make the power from the satellite useless. Need another renewable energy.

Hydrogen is being pushed by DOE and one company says it has solved the hydrogen production problem.

They propose using sea water and wind energy to make unlimited amounts of energy forever that is 100% green and renewable !!

Mazda is using hydrogen just like gasoline in their new car with 4 times the gas mileage.

Does every solar power venture have to involve solar panels? I've seen time and again articles and research showing focused thermal capture to be more efficient. Instead of trying to manufacture an acreage of silicon wafers why not just a large thin sheet of metal to create a mirror pointing at a collector? In space the problem of tracking the sun wouldn't even exist, and everything about the manufacturing would be so much more economical.

The solution to the energy issue is the solution to the number two killer, obesity. The government should issue out exercise bikes and stepper machines to every household and connect to the grid via low voltage trickle in-120 volt out parallel capacitors. People will loose weight while providing energy to the grid and cleaning the air. This will also reduce healthcare costs and food consumption which all utilize energy. The name of this program should be "ThinEnergy".

And if we just permanently plugged in the peopl we would have the "MATRIX"

21 billion for 1.3 million hp platform of 24/7 energy does not sound bad at all, but what would the fees be to keep it operational and what is the expected lifetime?

Looks like the Japanese will get some good, practical experience toward developing a future space-based weapons platforms, too. Kudos. For now, of course, it's purely a civilian energy project. Wait, where have I heard this before...

Damon, I think you heard about a "civilian" space solar power satellite being used as a weapons platform in the book titled Sunstroke, written by US aerospace engineer David Kagan. Sunstroke should really be made into a blockbuster movie because this book exposes the vast weapons potential of microwave-power-beaming satellites, and you know it's all true.

Sunstroke spells out quite clearly that such a space solar power station employing high-intensity microwave beams will be used as a devastating multi-pronged weapon: it can supply electricity to the military, be used to fry enemy ground troops, aircraft, ocean-going vessels, and also be used to disrupt enemy communications as well as destroy their agricultural capabilities. All in the guise of being a "purely civilian alternative energy project". Pure Genius!

Sunstroke spells out quite clearly that such a space solar power station employing high-intensity microwave beams will be used as a devastating multi-pronged weapon: it can supply electricity to the military, be used to fry enemy ground troops, aircraft, ocean-going vessels, and also be used to disrupt enemy communications as well as destroy their agricultural capabilities. All in the guise of being a "purely civilian alternative energy project". Pure Genius!

One word... F.. I.. C.. T.. I.. O.. N...

What a bunch of whining babies you're all becoming.

"Wha! It could be a weapon"
"Wha! It would never work"
"Wha! Industry was a bad idea and we should Leap Backwards 200 years"

You all make me sick!

The article and whole discussion is funny in a semi-tragical sense to me.

First of all everyone should really stop worrying about space weapons, we have enough destructive potential already and hell, we're doing a pretty good job at killing our fellow man and ourselves as it is now. At 21 billion a pop, you could probably build yourself a bunch of nukes and get the job done, especially since noone really has defensive capability against those yet.

Second of all, I'll join the camp that believes that we should be drilling down rather than going up. The Earth has tremendous geo-thermal potential which is for our purposes very comparable to the energy we can harvest from the Sun, and a combination of the two would probably service our needs for a long long time.

Third of all and saddest of all, without discarding the importance of scientific progress, we seem to be so engaged in the race to become the uber-human beings we read of in the sci-fi books that we are forgetting that being uber-human involved, first of all, to be human.

A large part of our popoulation is deeply submerged in poverty. While parts of the western world thrive and drive hybrid cars and put solar arrays into space, these people can hardly afford food, in the best cases, and have to drink muddy infested water in the worst.

Even if you gave them clean energy they would have nothing to do with it.

Cleaning up our act is good, but shouldn't we also be researching more proper ways to develop the dirt poor countries of our world, ways to get them water and food? Maybe if we spent more time on selecting reasearch projects more carefully there would be some coins left over for them.

Nuclear power stations, which avoid use of evil fossil fuels, are apparently a far too complicated alternative.

fossil fuel: solar derivative power.

d'oh

solar power satellite being used as a weapons platform

Well, de-orbit a soviet plutonium-powered spy satellite and hit London- same as an isotope dirty bomb. Possible?

A microwave platform in geosynchronous orbit above the equator, south of Japan. A diffuse beam as wide as a football field. Their targets would be limited and the damage potential remote. Wandering beams could be detected at a distance from atmospheric scattering. Scale-up efforts would take months and trigger worldwide condemnation and tangible threats from countries with ICBMs if necessary. Worst case, the platform gets shot down by the Chinese, or we invade California. Offensive potential- negligible. Relax.

A large part of our popoulation is deeply submerged in poverty.

Overpopulation- off-topic.

Even if you gave them clean energy they would have nothing to do with it.

Well thats the problem isnt it? People who do not buy into the culture cannot benefit from what it has to offer can they?

Adam, the main concern regarding power-beaming concentrated microwaves from orbit are the biohazards accompanying high-intensity microwaves, as explained in the book Sunstroke by David Kagan. Power-beaming satellites are being developed in Japan and the US. The US EPA is gravely concerned about the microwave irradiating of human, plant and animal tissues at the satellite's ground receiver; they say that it's powerful enough to heat up living tissue. And that's at ground level. That means passengers aboard an aircraft that accidentally passes through the beam could get flash-roasted like popping a dinner into your microwave oven. Birds too. Also the EPA is concerned about atmospheric heating and telecommunications interference as the beam microwaves its way through all layers of the earth's atmosphere. In addition the microwave heating effects and the massive injection of pollutants from the satellite launch vehicles will exacerbate global warming.

Otto, a solar power platform employing high-intensity microwaves is fully capable of frying the electronics of any anti-satellite vehicle used against it, as described in the book Sunstroke by David Kagan and the US OTA document on the subject. Also such a power-beaming platform is capable of directing its concentrated microwave beam at a select target in orbit (or in the air or on the ground) and prevent all radio commands from reaching the target by creating impenetrable electromagnetic interference. That's another reason why the race is on (despite the high price-tag) to be the first to orbit one of these microwave power stations.

The industrial revolution should never have happened.... Is this why cancer and diabetes still exist (acidic body and diet).... Let us prevent these off the wall ideas from being realized. We need the space elevator though to take the glory away from astronauts.

Wow, what is a Luddite (a paranoid one at that) doing posting comments on the web?

Great! Just what we need more waves and beams bombarding us and the planet. I guess it's a good thing the waves are invisible to us, otherwise we'd probably not be able to see anything else.

Also such a power-beaming platform is capable of directing its concentrated microwave beam at a select

Californian and Japanesian? satellite designs and intent would be well known by the intelligence communities of concerned countries. Collector area would give an idea of max power and capability. Refraction through the air at increasing angles would limit effectiveness beyond a certain area. I assume these things. And I agree this is being done now by those who need to be the first to do it.

Otto does not engage in idle speculation like those who don't believe all nations are not part of, and subsidiary to, a single, surreptitious Authority. Relax, everythings under Control.

Besides like I say china or India or SOMEONE would shoot the thing down- lasers, rockets, or their own RF platform. It is a sitting pot roast. A weapon would look a lot different from a power station- size, optics, control, power storage, multiple frequency capability. If the beam stopped, moved, or changed frequency everybody would know.

What does the book say to these arguments?

BTW, another energy alternative at climatemaster.com- a residential geothermal heatpump. What a good idea. I suppose you could draw ambient heat from any location depending on the depth you go to.

Otto, thanks for your pertinent comments, and I do suggest you read the book titled Sunstroke, written by US aerospace engineer David Kagan, as well as the US govn't Office of Technology document titled "Solar Power Satellites". They state that it's basically impossible is to "shoot down" such a giant power-beaming platform because the thing will be orbiting 22,300 miles above the Earth, is so immense in area (4 square kilometres) and could be quite capable of destroying any space-based attack vehicles, including nuclear-tipped or x-ray laser equipped spacecraft. And its appearance can be quite deceptive: no way to tell if it's a weapon or an energy station. Could be both.

Also it would take 24/7 constant infrared satellite monitoring of the power-beaming platform and ground rectenna to determine if its lethal microwave beam wandered from its designated path. Due to the extremely high cost of such continuous IR monitoring (especially in a global recession) this is unlikely.

I have posted this on other forums. I hope someone can tell me what I am missing.

The path loss for something like this using microwave is enormous. At 1GHz, there is 185dB of attenuation from geosync to the ground. At 10GHz, that's 204dB of attenuation. At 100GHz that's 224dB of attenuation.

To recover 1/2 the power with a 100% efficient dish antenna @ 1GHz, it's diameter would be 120,218 Kilometers. (or two dish antennas, one at the generator and one on earth 3,388 Kilometers in diameter)

I just don't see how this can be freezable. Is there something wrong with my math?

er, make that 3.388 Kilometers in diameter for the two smaller dishes.

ke4pjw, the actual proposed microwave frequency for power-beaming from geosynch orbit by either Japan's or California's PG&E project is 2.45 GHz. They state that such a frequency will provide adequate microwave energy to their ground receiving station (rectenna) to be converted into enough useful baseload electricity to power more than 150,000 homes. You may very well be correct that atmospheric attenuation will drop their proposed power level by a large amount. However it should be noted that the microwave power intensity at ground level will be determined by the exact size of their solar cell array and by the number of klystron tubes/magnetrons that the solar power station possesses, as explained in the book Sunstroke by author David Kagan.

Zugger, "Sunstroke" is a work of fiction. I appreciate that you like the book and thought the technological premise seemed realistic, but there's likely a great deal of "artistic liscense" going on there. Maybe you can find REAL research to use as backing to your arguments.

Also, since the Physorg staff pulled my cleverness (twice!) because it was "pointless verbage", I'm adding it here where it will be safe, piggybacked on my mild criticism, above. Here it is... "thin energy" would be more cleverly worded as "thinergy". Wow, jumping thru these hoops sucked what little funniness there was right out of this!

zuggernak,
The NSA and many others in many countries 24/7 monitor a LOT of things. These deathsats of yours will have a tiny unprotected little core which will go poof when hit by Chinese laser. You will be left with hectares of drifting sailcloth.

Relax! everythings under Control.

Dozer, you may want to read the Sunstroke book by David Kagan, as well as the US govn't Office of Technology document titled "Solar Power Satellites" that includes the US EPA's biohazard assessment of power-beaming from orbit via microwaves. The US EPA wants far more studies to be conducted regarding the microwave irradiating of human, plant and animal tissues at the satellite's ground intensity; they say that it's powerful enough to heat up living tissue. And that's at ground level. That means passengers aboard an aircraft that accidentally passes through the beam could get flash-roasted like popping a dinner into your microwave oven. Also the EPA is concerned about atmospheric heating and telecommunications interference as the beam microwaves its way through all layers of the earth's atmosphere. The heating effects could exacerbate global warming.

Thanks for your comment. Hope this helps.

Otto, these powersats that beam solar energy to earth via microwaves could be heavily-shielded, as described in the book Sunstroke by David Kagan and in US government literature, that effectively wards off attacks by lasers or missiles. Also, a major problem with power-beaming is the heating up of earth's atmospheric layers by this intense highly-focused microwave beam that will not only interact with cloud dynamics, but also add to global warming. Very negative effects. On top of all this is the serious issue of exposing the populace, plants and animals to a constant exposure of concentrated microwave radiation at and near the ground-receiving station.

All of the monitoring in the world will not alleviate these critical environmental issues.

Your highly pertinent comments are greatly appreciated. Thank you again.

Here's a concept... build the space elevator, build a network of space-based power platforms, beam that energy to collectors on the elevator's anchor, and beam the energy down a shielded conduit running down to the ground.

Richochet, another science writer besides David Kagan author of Sunstroke addressed space solar power-beaming. Arthur C. Clarke, a space elevator proponent years ago wrote a book titled Fountains of Paradise, the "bible" on space elevators. Clarke correctly described the catastrophic results if the 22,300 mile-long cable (conduit) connecting the space platform with the ground should snap (a likely scenario). The "cable car", its passengers and the energy conduit conveying the microwaved power would suddenly be in free fall, plummet into the Earth's atmosphere like space junk and burn up. That would cause the space-based, lethal solar power microwave beam to wander at random across the ground, striking population centers right and left. Very bad, indeed.

Only carbon "nano-fibers" that exist almost theoretically only in the laboratory could possibly provide the raw material for such a cable. But the cost is astronomical. Maybe Japan knows how to safely harness space solar power.

Darn you Ricochet for forcing me to agree with Zuggerjack on something. :) Specifically, any cable deployed of that length, especially when we start making it multipurpose - a climbing line AND a shielded power line) - would have to be strong enough to not snap under it's own considerable weight. Carbon nanotubes seems the way to go currently. While its convenient to run the power thru the cable, it could also be run from the same 2 stations, but parallel to the cable. That whould eliminate the need to extra weight on the cable and still allow the dual use of the airspace and the stations.

Dozer, you got it right here. Both Sunstroke author David Kagan and Fountains of Paradise author Arthur C. Clarke are correct in their assessment of the tremendous stress involved in deploying a shielded 22,300-mile-long cable capable of not only conveying heavy payloads to and from geosynch orbit to the ground, but also acting as a heavy-duty coaxial cable to carry at least 1 gigawatt of microwave power at 2.54 gigahertz frequency to the Earth for conversion into useful baseload electricity.

Theoretically, nano carbon-fiber filaments could handle very light loads from geosynch to the ground, but most unfortunately cannot be reinforced to any extent, for reasons you stated. Running the microwave power beam parallel to the cable as you stated could be done, but still wouldn't safeguard against serious mishaps that will occur if the solar power platform transmitting the concentrated microwave beam wanders from its "fixed" position.

Thank you for your valuable input.

Regarding the risk of the beam wandering away from the receiving station, it wouldn't be that difficult to have a couple targeting lasers on the satellite, so that if it goes off the mark it could adjust its aim and relative position, or shut down the beam entirely, if necessary. More concerning to me would be the risk of oscillation on the cable crawler from the effect of wind or satellite positional adjustment - you would REALLY want to not swing into the path of that beam, as you sloooowly crawled your way up or down the cable, and the possibility of stressing the cable to its breaking point during a oscillation event where it feeds upon itself are real.

Excellent analysis, Dozer. But we can't ignore Sunstroke author David Kagan's assessment in his book that there is a serious hazard in geosynch orbit regarding space junk collision or a deliberate ASAT attack on the power-beaming platform that could disable targeting lasers and the fail-safe microwave defocusing devices. It seems that multiple-redundancy back-up systems are needed here, but even they would be vulnerable to a series of deliberate ASAT attacks. This is where extra shielding may help.

You're darn right about severe oscillation impact on the space elevator's cable from terrestrial weather events and satellite fixed-orbit attitudinal correction. They could really over-stress the nano-cable to the breaking point. The weight factor forbids substantial reinforcement, as you well know, but there must be a way to beat these problems. That's why I'm hoping Japan's think tank that's behind their space solar power-beaming project will clue us in here.

Many thanks.