IAA says 'Yes We Can' to power plants in orbit

Should try out a test-station and see if it is cost effective (which I'm not at all sure about since launch costs for these systems would be substantial)

Advantages to space solar power compared to ground solar power are that it can occur without worry about adverse weather conditions and the costs of energy storage.

This is partially true. There is such a thing as space weather. Solar flares have forced sattelites to shut down in the past - and these systems would be very prone to those effects. Then there is the issue of storage: Depending on where you beam the energy down you will likely need some transport (as you want those beams to come down far from human habitation). Microwaves are affected by cirrus clouds to some extent.

solar collection does not bring carbon pollution,

The exhausts of current rocket technologies are extremely harmful to the ozone layer. Putting massive power production in orbit would mean many launches. This needs to be taken into account

I can't wait to see the results of the first misfire from a space laser.

Is the method of beaming down energy already so reliable that it can be done with a huge efficiency or are we looking at (i.e.) only a efficiency of 10%?

I can't wait to see the results of the first misfire from a space laser.

It should prove very interesting.

Is the method of beaming down energy already so reliable

It is reliable and the efficiency would be somewhere between 80 and 90%. But you need really large antennas (in space the thing would need to have an antenna 1 km wide, on the ground we'd need something 10 km in diameter)

Something we should also not forget: Taking energy from space means we are sending more energy to Earth than Earth would take up on its own (in effect increasing the size of earth as with respect to solar radiation).
All energy we create/send will eventually become heat. This will somewhat offset the gain in terms of global warming. Here utilizing solar energy that impacts Earth anyways is superior (wind, Earth based solar, hydro)

It is reliable and the efficiency would be somewhere between 80 and 90%.

I find that suspiciously optimistic. A microwave magnetron for example is only 65% efficient, and the recieving antenna and rectification can't be 99% efficient.

I find it hard to believe this would be cost-effective, but I sure hope so.

I find that suspiciously optimistic. A microwave magnetron for example is only 65% efficient,

I was referring to the beaming process, only (i.e. losses between sending an receiving antennas - which would manifest as heat in the Earth's atmosphere).

You are perfectly correct that the entire system efficiency will be substantially lower (especially if we use lasers - then the efficiency will go right down the drain because making laser light is a very inefficient process)

I find it hard to believe this would be cost-effective, but I sure hope so.

I did the calcs base on the ISS solar panels a few years ago on another forum. Getting 10% of Earth power needs from solar came out to about 400 trillion dollars (with about 4 trillion annual upkeep and replacement of degrading structures) and a 20 times overkill of the ozone layer from rocket exhausts. But that was based on PV, not mirror collectors.

If they are successful with wireless power/charging then this concept will be very likely.

I can't wait to see the results of the first misfire from a space laser.

lol, yeah one hit from a piece of space debris could leave a large scar on Earths surface.

As antialias_physorg noted, increasing the total energy to the earth from solar radiation will add to global warming. All of the extra energy will eventually be converted to heat.

Is global warming only a concern if it is caused by carbon dioxide? Because the article did not present any concerns about global warming.

I thought this idea was canned because we're not fond of the whole stray deathray thing.

I made a rough calculation a while ago to determine how many average nuclear reactors would be required to cover the entire global energy use and it worked out that roughly 40-50 new reactors per day for a year ( current) to have enough output.

Wiki says world use in 2008 = 142,000 TW/h

That can't be beamed to the surface safely.

As antialias_physorg noted, increasing the total energy to the earth from solar radiation will add to global warming. All of the extra energy will eventually be converted to heat.

Is global warming only a concern if it is caused by carbon dioxide? Because the article did not present any concerns about global warming.

Global warming caused by any heating of Earths surface is negligible if the excess heat can escape. The problem is CO2 which blocks this escape.

" Each would be several miles wide "

..yes, until they were shredded by micro-meteorites and dust.

, no ?

Global warming caused by any heating of Earths surface is negligible if the excess heat can escape.

True. but since we're not getting rid of the CO2 we already have the problem is larger with orbital solar than it is with Earth based solar.

Though this is probably really only a niggle. The added 'surface area' of the Earth due to space based collectors would be very small as a percentage of surface area of the Earth.

The losses of the microwave beam in the atmosphere might be more of a problem as it's starting to heat up stuff at very high altitudes - and we really don't know what kind of effects that will have on weather patterns. (If the HAARP project is anything to go by - though at a slightly differnt frequency - then it's not entirely without ffect)

Wouldn't it just be easier to not consume energy wastefully and avoid the need to build impractical and foolishly expensive energy harvesting white elephants in space?

Building better powergrids and harvesting sunlight in the deserts, sounds like a better plan. We do not need 100% up-time on solar panels if combined with hydro, nuclear etc.

Wouldn't it just be easier to not consume energy wastefully and avoid the need to build impractical and foolishly expensive energy harvesting white elephants in space?

That would make too much sense O:

I am jaded perhaps, but I don't think many people are willing to commit to altering how they are used to living.

Wouldn't it just be easier to not consume energy wastefully and avoid the need to build impractical and foolishly expensive energy harvesting white elephants in space?

You want to bring common sense into this? Are you crazy?

Several-mile wide objects in space. This sounds like an engineering challenge beyond anything we've accomplished off-planet. I wonder how this would compare to the technical challenges of assembling and maintaining the ISS.

Wouldn't it just be easier to not consume energy wastefully and avoid the need to build impractical and foolishly expensive energy harvesting white elephants in space?

In a word, no.

Population growth remains unchecked and energy demand is expected to skyrocket for the foreseeable future (one could make the case that in an increasingly technical civilization, energy demand will grow on a constant basis). Governments have shown very little ability to keep either in check.

the whole concept sounds outlandish and exorbitant. The sort of thing that will never get off the ground, and for good reason. The sort of thing that is purely an academic exercise, and will be looked back on in 30 years with jolly ridicule.

There are much better ways to cater the energy needs of a growing global population even with today's energy tech, let alone with rapid developments in harvesting here on the ground and amazing properties of materials we are only beginning to understand.

I clicked the article thinking that the main picture was a space elevator...

Anyway, I always had mixed feelings about solar-in-space. Even assuming that it has double or triple the efficiency, wouldn't it make more sense to just put double or triple the same amount of solar panels but on Earth?

Tell me. How many square miles of desert would it require to capture the same amount of energy per day per sq. km of space solar panels. Let's say, for arguments' sake, it was as high as a factor of 100. It would still be way more cost effective to use the desert. Let's stop trying to find a complex solution to a simple problem.

wouldn't it make more sense to just put double or triple the same amount of solar panels but on Earth?

Yes it would. Mostly because having a number of solar panels in orbit is hundreds of times more expensive than having the same number here on the ground (including some means for storing excess energy production for night time/bad weather conditions).

But I could actually see a use for largish space based solar power plants: Providing power (and possibly impulse via solar sails) to other sattelites.

Wouldn't it be great if sattelites didn't have to pack their own batteries, reactors or photovoltaics but simply a microwave antenna which they point at the nearest solar power plant?

Could bring launch weight, size, and cost of new sattelites down substantially while increasing the lifetime of sattelites at the same time.

Tell me. How many square miles of desert would it require to capture the same amount of energy per day per sq. km of space solar panels.

Solar constant at the top of the atmosphere is about 1.3-1.4kW per square meter.

Solar constant at ground level (desert) is about 1kW per square meter or about 800W in northern latitudes (midday).

Given that, on the ground, you have no energy production during the night and lesser energy production during morning/evening I'd estimate that the effectiveness at ground level is about a quarter that of something of the same size in orbit.

And let's not forget maintenance issues. Anything that breaks in space stays broken (or anything that fails upon launch is a total loss). On Earth repairs and maintenance are more intensive, but also
a) a LOT cheaper
b) feasible

Spectrum is different in orbit, too. Of those 1.4kW more is high energy radiation than whatreaches the ground - which is harder to use.

But I could actually see a use for largish space based solar power plants: Providing power (and possibly impulse via solar sails) to other sattelites.

Although it would be a bit risky to have so many critical satellites dependent on just one. If that one were to go down (or be shot down)...

I guess if there were a lot of them it'd be alright.

As an energy source, ludicrous. Now, if you were looking for something to make nuclear weapons look like kiddies toys...

At first sight it seems like a «green» idea.
But it is not.
We now have to struggle with the greenhouse effect, so every extra lumen we bring from space to the surface becomes an extra energy input to the atmosphere.

Make no mistake:
I like this idea. It could be very usefull on Mars or on the Moon, but here on Earth we'll have to find a way to reduce sunlight income (with a giant space sunshade?) BEFORE thinking bringing more heat to the whole sustem.

Current power production is on the order of 15 Tw The Earth intercepts 3850000 exajoules (EJ) of sunlight per year. So, we are talking a factor of over 100,000.

Forget the beaming... put these on the ends of space elevators please :)

Why is DARPA (Defense Advanced Research Projects Agency) not funding this? The ability to simply vaporize anything, anywhere and at any time, all the while being able to defend yourself from incoming ASAT (anti-satellite) satellites is priceless. We would not need the 5th fleet, the 7th fleet, or any fleets. Forget UAS (Unmanned Aircraft Systems) When you have the "Eye in the Sky" that can stare you down. Who needs a standing (or sitting) Army?

Nukes would be passe in comparison.

Oh, I think that I just answered my own question. Darn.

Do it right (pair it with lasers?) and you'd be able to vaporize individuals.
Nixon would have LOVED it (talk about people on your "enemies list" just evaporating)....

Come-on: Before someone else beats us to it and while we still have a semblance of an economy (eh - credit card) left that "might" be able to "pay" (eh - Borrow) for it.

Talk about be careful what you say or "god" will strike you down....

It is reliable and the efficiency would be somewhere between 80 and 90%.

I find that suspiciously optimistic. A microwave magnetron for example is only 65% efficient, and the recieving antenna and rectification can't be 99% efficient.

Rectennas are about 80% efficient, but you are right, there will be losses at the transmission end.

The big problem with the power satellite scheme is the cost (and energy expenditure and pollution) of getting all this junk into orbit.

This will never happen until they can get large scale manufacturing facilities on the moon.

Hmm seems like an interesting idea. But I wonder how the heck are htey planning to keep the mirrors intact with all the space junk?

This will never happen until they can get large scale manufacturing facilities on the moon.

And we had better solve the energy crisis WAY before then. If we wait till we get a big factory and settlement up there then we're screwed.

Come-on: Before someone else beats us to

There's a couple of interanational treaties forbidding that kind oif shenannigans and...oh...right...this is the US we're talking about. Isn't that the country that holds, by an enormous margin, the record for most broken treaties since it's founding? My bad. Go ahead. Build space lasers. Do.

Satellite basically beam signals down all the time with great accuracy...

I think it's a great idea, but what happens when it has finished it use. Thinking of it falling back to earth when it is so large? Are they going to build it so it can be easily taken apart, and not just falling back to earth. I mean the consequences of something that big falling back to earth would be horrendous if it landed on a populated area.

You guys are really in the dark, one example is that in space you could use supercooled superconducting equipment which would increase efficiency. Also satellites can now be built very insulated to withstand most solar flare phenomenon, you're thinking of older tech.

But the most important point here is that is opens new horizons, electricity powered spacecraft, if magnetic or microwave propulsion becomes prominent we could colonize the entire solar system while we habitate in luxury.

Not to mention provide a living, work food and a place to sleep for possibly a trillion humans, WITHOUT compromising the glorious planet which seeded us. We could turn earth into a wild life reserve and spend our time exploring the wonders of the universe.

But it's going to take support and grunt work now to even survive the many coming apocalypses, superviruses, resource shortages, wars, famines and all the other shit that happens when we don't work together and work smart!

one example is that in space you could use supercooled superconducting equipment

In space, getting rid of excess heat is major problem (no convection losses - just radiation losses which are little). And since these objects will be in the sun all the time they will get a lot of heat. Note that the lifetime of space telescopes is limited by when their _coolant_ runs out.

Also satellites can now be built very insulated to withstand most solar flare phenomenon, you're thinking of older tech.

Most isn't enough. One good one and you're out a all your multi trillion dollar power plants. With NO way to hide them from it.

electricity powered spacecraft, if magnetic or microwave propulsion

For magnetic propulsion you must have a field to work against. This would only work very close to Earth (and there only poorly).

Microwave/laser propulsion is a one way trip. And the boost is only for an extremely short duration. Not nearly enough for interplanetary flight.

There's a couple of interanational treaties forbidding that kind oif shenannigans and...oh...right...this is the US we're talking about. Isn't that the country that holds, by an enormous margin, the record for most broken treaties since it's founding? My bad. Go ahead. Build space lasers. Do.

Which treaties are you referring to re: forbidding that kind of shenanigans? Do you mean space weapons specifically?

As to your ludicrous comment re: treaties broken by the U.S., don't want to confuse you with any facts that might cloud your exuberant rant, but you are only fabricating a story. A fantasy as it were. Nicely done. Let me guess, you're going to quote the Native American treaties?

a little techno advancement here, a little precision aiming system there. vuala! an awesome super power weapon. MWHAHAHA!

This would perhaps only be really economically feasible if the hardware was manufactured in space, by space probes that can process e.g. asteroidal/lunar material into solar cells, propellant, and complex electronics.
BTW the EM beam from space can be made harmless and be collected by wire-thin antenna arrays.

Is the method of beaming down energy already so reliable

It is reliable and the efficiency would be somewhere between 80 and 90%. But you need really large antennas (in space the thing would need to have an antenna 1 km wide, on the ground we'd need something 10 km in diameter)

Not if masers were used.

How about this scenario? Terrorists break into (or hack) the satellite control center and aim it at a major city. Worse yet, aim it at something toxic, like a nuclear waste storage site.

Hmm seems like an interesting idea. But I wonder how the heck are htey planning to keep the mirrors intact with all the space junk?

Just hire some alien workers.

Edwarsc... American Idiot!

Which treaties are you referring to

Outer Space Treaty
http://en.wikiped...e_Treaty

As for broken treaties (or simply not signed ones that should be blindingly obvious to any being that calls itself even remotely human)
http://www.vote.org/treaties

more energy means more hot what about global warming?

won't need drones anymore.

How about this scenario? Terrorists break into (or hack) the satellite control center and aim it at a major city. Worse yet, aim it at something toxic, like a nuclear waste storage site.

Oh, come on, they'll be using Windows 10 by then. I'm sure it will be perfectly safe. hehe

Which treaties are you referring to

Outer Space Treaty
http://en.wikiped...e_Treaty

antialias, I commend you for the intelligence and rationality you commonly show in your posts. Your analyses are well thought out, and you have very relevant information to share.

On this one, however, it seems that you may be letting your personal opinion sway you. First, I looked around quite a bit and was unable to find anyone who had ever compiled a definitive listing of every treaty ever recorded between two governments, and a corresponding list of when the treaty was dissolved and under what circumstances.

So, first, it's very difficult to say that the U.S. has broken more treaties that anyone else. Second, it's partially subjective anyway. For each treaty, you'd have to analyze the circumstances and determine if one, both, or multiple parties pulled out. Finally, it's inappropriate to include "treaties the U.S. should sign" in your list.

These satellites would not have to be nearly as rigid as earthbound panels that have to stand wind stresses, for instance. Hence lighter materials. Miles of anything in space would need to be in high orbit. Thankfully this is not so much a problem to laser transmission as losses other than beam divergence will incur principally only in the atmosphere which is by comparison only a few tens of miles as opposed to a twenty thousand mile 'high orbit' Be really neat if a strong tether was developed for a space elevator as that would facilitate mass production of this planetary net. There will be a need for a crew for anything this big, or if intermittant at least a maintainence and security crew quarters fully equipped. We will need to keep the ISS in use ..forever..as a base for orbital transfer shuttles for construction materiel, equipment, robots, and personnel. Non repairability is NOT an option. And crewed vehicles VERRY resistant to 'hackers'.

You have everything totally wrong:

1) ISS is low orbit (400km). This stuff would be high orbit (geosynch, which means 36000km). No constant human presence possible with current tech at those altitudes (would be enormously expensive).
2) Rigidity would have to be just as much as on the ISS (which is substantial and not much different than on Earth). The launch weight for the ISS panels is several tons a piece (and they are SMALL compared to what you would need here)
3) Lasers diverge. Over such a distance they diverge subtsantially. Creating a high power laser beam is a very inefficient process. We're talking 0.01% to 0.1% of the energy put into a laser apparatus actually comes out as laser light. The rest is wasted (which just made the power plant 1000 to 10000 times bigger than one on Earth for the same output).
4) Non repairability would be the only way to go. Fire and forget.

IMO this would just become another government(re- taxpayer) funded corporate boondoggle...
Remember the old saying - "If it sounds too good to be true - it usually is..."

Apart from generation, transmission and conversion inefficiencies, the size of the system would cause the solar sail effect as well. Station keeping would be necessary. Even ion propulsion thrusters need propellant. This has to be replenished by automated supply ships, serviced or replaced when broke down.
On the other hand, if the system is REALLY big, we possibly can position it in a way to act as a sun shield too, reducing the effect of beaming extra energy to the Earth. Depending on the design and material, the collectors could be spun to provide rigidity without weight penalties, and the underside of the collectors would be in shadow, enabling the use of minimal cryogenic cooling for superconductors in the machinery.
Still the biggest show breaker would be the annual meteor showers. Their swath are big enough to hit Earth that I doubt there is anywhere near Earth that is safe from them. The system must be able to survive and function with this regular bombardments.

I think the way to do this right would be to set up all the infrastructure needed to make power plants on the moon. While it will surely increase the initial costs to trillions of dollars in the long run it would be worth it.

Just having raw materials in storage up on the moon opens up wild new frontiers.

If you have mining and refining equip on the moon all you have to do it send up a series of small factories to turn the semi-processed materials into components.

You could get to the point where everything is ready up there and you send some humans up to assemble anything that can't be easily done remotely. From there the moon is much easier to launch power satellites from, not to mention you could beam back the sun energy to the moon instead of earth.

I hardly think cooling would be a problem with a solar satellite, the panels would not be thermally connected to the power distribution. I thought telescopes needed to be cooled because the lens needed to be a consistent even temp

Is global warming only a concern if it is caused by carbon dioxide? Because the article did not present any concerns about global warming.

It's a different order of magnitude. Once the fossil fuels are burnt they have expended their useful energy; but they add to the earth's radiative forcing for a very long time.

The current 2.5 W/m^2 anthropogenic GHG forcing is equivalent to adding ~45 kW per capita of heat to earths atmosphere continously, night and day.

The average power consumption(primary energy, i.e. including the ~2/3 that is rejected as waste heat) of the world is ~2.3 kW per capita. Even the US is only ~10 kW/capita.

Beaming even 10 kW/capita to the Earth from space(which allows for ~2/3 of beamed energy to be lost, as with current primary energy consumption) would not be a serious problem.

Power satellites would heat the Earth very unevenly; where the receivers and consumers(mostly cities) are. Greenhouse gasses are global; this would be mostly local heating.

There are 3 problems with this endeavor; the most obvious is the cost to get all the satellites up there; and how long will they last. The second issue is if first you convert to electricity then back to laser or microwave; there is a loss in conversion efficiency; you are converting twice. Finally, this is just a clever conception for the star wars defense program.

However on the flip side, eventually it could be a planetary defense, concentrate lasers from all satellites and aim at asteroid; probably won't blow it up, but should be enough to deflect it off course.

You know, ....if we could manage to keep our infrastuctures down here from crumbling first, then maybe I could see this as something worth attempting. Otherwise, it's completely unrealistic to think something like this is even viable scaled down. The only way this would ever be possible is with some newfangled highfalootin' metamaterials that are almost entirely self-healing, even in the harsh environments in space.

I wonder how much junk will be floating around our planet in 100 years.... Has anyone done projections based on accumulation rates since we started going to space ?

Dangerous solutions to imaginary problems. no thanks.

1. Solar power satellites would only be profitable if built from lunar materials. They have been studied since the 1970's by many nations/groups. Japan is seriously thinking of building one, since it must import most of its engergy needs.
2. Orbiting at 24,000 miles, they will not crash to earth for millions (?) of years, hence, no threat.
3. Microwave transmission is safe and effective, and proven. These proposals would not be useful as weapons.
4. Orbital debris is a serious problem, but mostly from LEO, not GEO. Check NASA's website on this. http://orbitaldeb...asa.gov/
5. Damage from micrometeoroids etc is a concern, so the above questions on maintenace are valid. Best guess is that the satellites would have to be maintained from a lunar base.

No need to hyperventilate or exaggerate the issues, just try Google once in a while. There is a lot of good information out there.

As antialias_physorg noted, increasing the total energy to the earth from solar radiation will add to global warming. All of the extra energy will eventually be converted to heat.

This will offset fossil fuel use which will remain in the ground, unburnt. No net heat gain.

No constant human presence possible with current tech at those altitudes (would be enormously expensive).

You are not considering advances in robotics for construction and maintenance.

Rigidity would have to be just as much as on the ISS (which is substantial and not much different than on Earth).

Why? Mirrors could be extremely diaphanous and filamentous structures. No big metal cans full of delicate electronics and people, or silicon panels for that matter.

I thought projects like this were already in the works?
http://www.livesc...ace.html
http://inhabitat....0-homes/

This will offset fossil fuel use which will remain in the ground, unburnt. No net heat gain.

I'm not sure that can be stated with certainty. The determining factor is how much energy we need for use - and how much losses are generated within the atmosphere along the entire chain until that X amount of useful TWatts are produced.

Gut feeling tells me that using coal/oil/gas is worse. But my gut feeling also tells me that putting up regenerative powerplants (wind, wave, solar) on Earth is much better in that respect.

You are not considering advances in robotics for construction and maintenance.

And how good are these advances? We stills send out astronauts to the Hubble telescope to swap out rectangular blocks (a very basic task comparing the maintenance issues that can arise in high orbit). We are talking about whether we can do it NOW. If we can do it in 100 years then orbital power plants aren't the solution to today's problems.

1. Solar power satellites would only be profitable if built from lunar materials.

Hard to manufacture things like mylar and composite materials and nanotubes etc on the moon.

And how good are these advances? We stills end out astronauts to the Hubble telescope to swap out rectangular blocks

The hubble is -what- 40 year old tech? And it was designed to be serviced by humans on the shuttle. Have faith in Progress. And the japanese.
http://www.google...kZZtXIAA

As I said: what good is it if we can do it in 50 years? By that time we can have already switched over on Earth for MUCH less money, environmental impact and with no possibility that a country will use that tech as a choke hold on others by either controlling who gets what (or by another country threatening to destroy it)

They could beam-microwave entire fields of popcorn!!!

Rural drive-in movie theaters are bound to make a comeback!

AP: I somewhat agree, but 50 years ago they said we would have nuclear fusion by now for everyone. Still waiting...

As I said: what good is it if we can do it in 50 years? By that time we can have already switched over on Earth for MUCH less money, environmental impact and with no possibility that a country will use that tech as a choke hold on others by either controlling who gets what (or by another country threatening to destroy it)

If you're referring to robots, we already control RPVs on the other side of the globe. Orbital power stations also have the potential for weaning other countries off oil by selling them power. And it can certainly help to make owner countries independent of OPEC.

OOp messed up. IPhone 3G

but 50 years ago they said we would have nuclear fusion by now for everyone. Still waiting...

Exactly my point. If we put our chips on technology yet to be developed (robotics that can handle that kind of complexity, orbital delivery and maintenance systems for multi gigatonne payloads, etc.) we'll be here in 50 years and not see one of these contraptions.

Not saying that its impossible or won't be done some time in the future - but it's not doable in the timeline we have for affecting anything down here
- weaning us off oil
- fight global warming
- getting rid of nuclear

But we DO have the technologies for doing it down here for a fraction of the cost. Less 'SciFi'-glitzy...but definitely more realistic and with all sorts of added benefits (less centralization, availability of incorporating developing countries, ... )

AP: I somewhat agree, but 50 years ago they said we would have nuclear fusion by now for everyone. Still waiting...

Haven't you heard the good news? Rossi finished that task.

Satellite basically beam signals down all the time with great accuracy...

Not saying that its impossible or won't be done some time in the future

I used to think this about ISS back when they decided to build it. 'How were they going to build that thing?' I was surprised when i read about components being made, launches planned, etc. And now here it is and they're already talking about decommissioning it.

Military projects are often begun on the confidence that tech developments along the way will make it possible. Think tanks make projections like this all the time. It behooves the military to begin developing applications NOW as opposed to waiting for someone else to beat them to it.

RPV tech exists now. Construction of massive space structures has been proven. Note the timeline between the wright brothers and Dresden. Remote assembly of structures DESIGNED to be constructed that way, will be MUCH easier, faster, and cheaper than humans in space suits trying to turn screws

We're much further along, relatively speaking, than the wright brothers. Think perhaps Alcock and Brown vs Dresden.

But we DO have the technologies for doing it down here for a fraction of the cost. Less 'SciFi'-glitzy...but definitely more realistic

And consider whether it makes any sense to invest in an infrastructure which will be obsolete in 30 years? I am sure think tankers are earning good money working through these issues right now.

I used to think this about ISS back when they decided to build it.

And you know how long that took from first conception to actually getting the thing up there? First ideas were being chucked around in the early 1960's. Concrete concepts being developed in the early 80's. And THEY didn't need to invent entirely new rocket systems (if we use the current rocket technologies/fuels then CO2/global warming will look like a picknick compared to what the amount of needed launches would do to our atmosphere)

And that was in a time when countries had resources and money to spare (the 90's were an unprecedented boom phase).

Construction of massive space structures has been proven.

But you have looked at the timeline and the cost figures? If you haven't you should. Then extrapolate (even with economics of scale) to something a mile wide in HIGH orbit(!)

Then to MANY such somethings.

Doable and sensible are not the same thing.

And you know how long that took from first conception to actually getting the thing up there? First ideas were being chucked around in the early 1960's.

-Same with orbital power stations.

Concrete concepts being developed in the early 80's

-And they're working on these now.

And THEY didn't need to invent entirely new rocket systems

The shuttle was a revolutionary system begun without such critical tech as heat tiles and o-rings. You could even say that the shuttle slowed the advent of ISS as it could have been built using conventional vehicles. But the shuttle was primarily a military project.

At the other end of the spectrum the manhattan project was committed to, and accomplished with breathtaking speed, on little more than theory.

Consider the timeline between the model T and the interstate highway system.

The shuttle was a revolutionary system begun without such critical tech as heat tiles and o-rings.

Which have no environmental impact. Rocket fuels do (they are major ozone-killers among other things. The only reason why this has not affected the ozone layer much is because the flights are so few and far between)

Consider the timeline between the model T and the interstate highway system.

What the hell does this have to do with anything in this article or discussion?

There are certain limits here which we cannot ignore. It takes X amount of energy to get something of mass Y into high orbit. That sort of energy has to come from reaction mass (i.e. rocket exhausts).

And no, you cannot make these stations very flimsy because they have to be reoriented to point at the sun. So either you pack them with a lot of nozzles and fuel (which means a limited lifetime or very expensive/dangerous refueling trips) or make them rigid to use solar sail methods.

I think the article is just saying we CAN do a thing and not that we GOING to do a thing.

The whole concept is a study in "what-if"', not "what-when".

If we lived in a "Star Trek" world where money was no object, we'd be trying a LOT of these kinds of projects. However - we don't...

I think the artice is just detailng the fact that we CAN do a thing, not that we're going to...
If we lived in a "Star Trek" world where money was no object, we'd be trying all kinds of these projects. However - we don't...

environmental impact. Rocket fuels do (they are major ozone-killers among other things. The only reason why this has not affected the ozone layer much is because the flights are so few and far between)

Depends on what they use. Solid fuel - yes. Lox/LH2 - no. Mass drivers - no.

What the hell does this have to do with anything in this article or discussion?

YOU said

but it's not doable in the timeline we have for affecting anything down here

And I gave an example with a timeline similar to:

- weaning us off oil
- fight global warming
- getting rid of nuclear

Except that, by the time YOUR solutions are fully implemented, they will most likely be obsolete. Big waste.

you cannot make these stations very flimsy because they have to be reoriented to point at the sun.

During the course of a year an array will need to rotate. Slowly. Continuously. And adjustments made in the same way.

Tensile structures supporting composite fabric can be VERY light yet very rigid.

A few startups:
http://www.spaceenergy.com/

"This follows Solarens recently signed deal for the first-ever power purchase agreement to deliver 200 megawatts of solar energy from space with Californias Pacific Gas & Electric."
http://newenergya...r-power/
http://www.solarenspace.com/

Research and testing of similar structures is ongoing:
http://en.wikiped...lar_sail

I think the artice is just detailng the fact that we CAN do a thing, not that we're going to...
If we lived in a "Star Trek" world where money was no object, we'd be trying all kinds of these projects. However - we don't...

Correction - these things are being designed, funded, and prototypes WILL be in orbit in a very short time.

Liquid propellant have their advantages and disadvantages
http://en.wikiped...nt_Types

Mass drivers - no.

No. That's Sci Fi.

Except that, by the time YOUR solutions are fully implemented, they will most likely be obsolete. Big waste.

How will hydro plants, solar power plants and windfarms be obsolete? Especially when they are orders of magnitude cheaper, available to everyone (even low tech countries), decentralized, unable to be sabotaged,...

During the course of a year an array will need to rotate.

Hmm..look at this timelaps of the ISS. Looks like the panels are rotating a bit faster than once a year.
http://www.youtub...o7w_RiI4

Tensile structures supporting composite fabric can be VERY light yet very rigid.

Then why aren't they used on ANY sattelite? Seems like NASA would eat that up as a means of saving weight.

No. That's Sci Fi.

More tech currently being developed that AP is blissfully unaware of:
http://www.kurzwe...-by-nasa

Hmm..look at this timelaps of the ISS. Looks like the panels are rotating a bit faster than once a year.

Ha. Power stations will be geosynchronous. Duh. Youre not even trying are you?

How will hydro plants, solar power plants and windfarms be obsolete?

Hydro - environment, siltation; solar - better in space; windfarms - cant run foundaries, subways, etc.

Especially when they are orders of magnitude cheaper,

At present?

available to everyone

So is wood -?

(even low tech countries),

Revisit pic above with beam pointed at cameroon

decentralized,

So? But there will be many of these, owned and operated by many different groups.

unable to be sabotaged,...

-In orbit? 'Ooh the caliph blew up our mojave ground station.' 'So point the beam at the Death valley array.' 'Ay sir captain sir.' 'And how about at islamabad for a few hours first?' 'No prob.'

Then why aren't they used on ANY sattelite? Seems like NASA would eat that up as a means of saving weight.

There is no satellite of a configuration which would make this structural system preferable. But there will be at least one very soon:
http://www.davidd...ope.html

-with many more to follow-

Power stations will be geosynchronous.

So no maintenance. Great. But either you rotate your antenna all the time or your panels.

So is wood

No, not in the poorer areas. Not in Africa or the like. You need a lot of wood for one person. This is not sustainable. Problematic in cities, too.

windfarms - cant run foundaries, subways, etc.

They do already run all of those (why shouldn't they be able to? Power is power.)

Revisit pic above with beam pointed at cameroon

And who owns the sattelite? Who owns the power? Certainly not Cameroon. Better for them (or anyone else) to have their own, cheap power plants.

In orbit?

China has shown they can blow up sattelites in orbit. So can Russia or the US. "He who can destroy a thing controls a thing".

As for the panels: The Webb's telescope mirrors are quite rigid. As are its solar panels (which are on the bottom).
http://www.jwst.n...er5a.jpg
The only thing flimsy is the 'heat' shield.

So no maintenance

Robotic.

But either you rotate your antenna all the time or your panels.

Slow continuous rotation. Like the moon. Periodic adjustment for solar wind etc.

No, not in the poorer areas. Not in Africa or the like. You need a lot of wood

Stop right there! I was being rhetorical.

They do already run all of those (why shouldn't they be able to? Power is power.)

Are you saying that solar and wind farms power specific aluminum and titanium refineries? I should like to see your evidence for that.

And who owns the sattelite? Who owns the power? Certainly not Cameroon.

And where pray tell does Cameroon currently get their power and fuel?

China has shown they can blow up sattelites in orbit. So can Russia or the US.

Easier to destroy ground-based infrastructure than huge multiple protected satellites 25,000 mi away.

"He who can destroy a thing controls a thing".

This does not google.
Cont>>

Robotic.

High orbit shuttling of spare parts and robotics for complicated maintenance is SciFi for now.

Are you saying that solar and wind farms power specific aluminum and titanium refineries? I should like to see your evidence for that.

They can do it like anyone else can do it over here: Buy X amount of Megawatt per year from the energy provider as alternative energy. The provider is then obligated to put X amount of Megawatts from alternative energy sources into the grid.
It is not necessary to put the amount of energy into the grid at the same time that it is used at the factory. Simple.

And where pray tell does Cameroon currently get their power and fuel?

Cameroon could get it from their own power plants. Space based solar is certainly not going to be theirs.
But Cameroon is a perfect example (from the wikipedia site on energy in cameroon)

Nearly 60% of the power from these [hydroelectric] stations goes to the aluminum smelter at Edéa

As for the panels: The Webb's telescope mirrors are quite rigid. As are its solar panels (which are on the bottom).
http://www.jwst.n...er5a.jpg
The only thing flimsy is the 'heat' shield.

Correct. But they are far from flimsy. They need to resist torque and dampen vibration from from mirror movement and temperature changes.

Tensile structures can be extremely strong and rigid for their weight. Space elevators will be tensile structures. Materials tech currently limits their use and related tech such as inflatables in the harsh environs of space, but not for long. Their inherent economy will make them predominant in the near future.
http://www.bigspa...res.com/

High orbit shuttling of spare parts and robotics for complicated maintenance is SciFi for now.

And as I showed you in the links I posted, they are being paid for and engineered for deployment in the very near future. This is therefore sci fact.

And Cameroonian hydro power, or any hydro power, is magnitudes above what can be produced with solar and wind. And siltation and environmental disruption make hydro a very poor investment compared to space-based solar, as one example.

Of course there is no reason Cameroon couldn't commission the construction of their own space plants, like California? Or at least lease rights from others, like California. This arrangement is typical among civilized nations yes?