How Japan Plans To Build Orbital Solar Power Stations

the_newsbeagle (2532562) writes "Solar power stations in orbit aren't exactly a new idea — Asimov set one of his stories on such a space station back in 1941. Everyone thinks it's a cool idea to collect solar power 24 hours a day and beam it down to Earth. But what with the expense and difficulty of rocketing up the parts and constructing and operating the stations in orbit, nobody's built one yet. While you probably still shouldn't hold your breath, it's interesting to learn that Japan's space agency has spec'd out such a solar power station."

Comments

Blofeld-San's new proposal approved

[sandbagger]

Seriously, this is right out of a James Bond story. What amazing times we live in.

Re:Blofeld-San's new proposal approved

[Joe_Dragon]

Just trun on no disasters and it will be fine.

Re:Blofeld-San's new proposal approved

[K. S. Kyosuke]

That would be a Sun-ami, right?

Re:Blofeld-San's new proposal approved

[jcomeau_ictx]

_Dark Rivers of the Heart_ by Dean Koontz. the sat is nicknamed Godzilla and a programmer, Ellie, has a backdoor into it. great book.

Re:Blofeld-San's new proposal approved

[N_Piper]

I think that was the unique selling point of the GX-9900 Gundam X.

Re:Blofeld-San's new proposal approved

[HornWumpus]

Koontz: when Steven King books have too many big words for you.

Re:Blofeld-San's new proposal approved

[Papaspud]

Or are too long and repetitious.....................

Re:Blofeld-San's new proposal approved

[AlphaWolf_HK]

When I need to get an evil villain job done, at first I thought nuking it from orbit was the only way to be sure, but if you have one of these then you officially have more than one way to be sure. Convenient times we live in.

Re:Blofeld-San's new proposal approved

[gzuckier]

The Fab Four of scary writing Steven King=Paul McCartney Peter Straub=George Harrison Clive Barker=John Lennon Dean Koontz=Ringo Starr

Re:Blofeld-San's new proposal approved

[nobodie]

Unlike the original fab four, I have only read one book of one of these people.
I was stuck in Vientiane Laos for a two days wait for a bus back to Chiang Mai Thailand and wandered into a used book store. I bought the thickest book I could find, for an extravagent amount of money and headed back to the guesthouse to crash and read trash. I realized that this book would be challenging, as in, "such a horrible piece of trash; self-indulgent author's self-congratulatory mental masturbational word landfill that i would be seriously ill by the end of it. I was, and still am: as in I can still feel the sticky crust of crap from that book whenever I think of it.

If you're just beaming it down to earth anyways

[mark-t]

why not just collect it from the ground in the first place?

What's going to make collecting energy on the ground from a satellite more efficient than collecting it from the sun?

Re:If you're just beaming it down to earth anyways

[Maury Markowitz]

> why not just collect it from the ground in the first place?

Exactly.

> What's going to make collecting energy on the ground from a satellite more efficient than collecting it from the sun?

In theory you don't have night, so you get twice as much hours of sunlight. Add "cosine error" and the lack of weather, and you're up to five times.

But then you have to throw away half on the way down to the earth. And then the panels last half as long in space. So in the end it's a *very* small *theoretical* advantage.

Which is, of course, utterly wiped out by the cost of launch. And everyone knows this. But the guys proposing these things are not power companies, but space companies. As is the case here, it's JAXA, the Japanese space agency. Everyone outside the space field is completely aware of the fact that this is an utterly ridiculous idea.

Re:If you're just beaming it down to earth anyways

[alexander_686]

2 reasons.

First, you don’t have to worry about your power going out at night. These things are so far away that the earth’s shadow will rarely fall on the array.

Second, in theory cells in space should be more efficient then cells buried underneath the atmosphere. I am not sure if they can overcome the practical problems to make it actually more efficient.

Side note – the US military is also looking at this. Beaming power to remote locations could be more efficient then hauling fuel. Power could be beamed to drones, giving them unlimited endurance.

Re:If you're just beaming it down to earth anyways

[Maury Markowitz]

> First, you don’t have to worry about your power going out at night

But that's not a problem we actually have. Baseload power is currently selling for 2 to 3 cents, peak power is up into the 20's. No one is going to build a space-o device to provide something we have trouble giving away.

> cells in space should be more efficient then cells buried underneath the atmosphere

Actually, the opposite is true. Cells, silicon ones anyway, are more efficient under the air. It has to do with their band gap.

> Beaming power to remote locations could be more efficient then hauling fuel

The problem is that all you're doing is replacing the array of solar panels with an array of dipoles. The increase in energy density is about 50%, so you need a field that's almost as big as normal PV. There's really no advantage here.

Re:If you're just beaming it down to earth anyways

[gstoddart]

What's going to make collecting energy on the ground from a satellite more efficient than collecting it from the sun?

Probably the ability to do it for more hours than you would have daylight?

If there exists an orbital path which can see the sun 24 hours/day, and that same orbital path lets you see the receiving stations, say, 18 hours/day ... you get more access to sunlight than you would otherwise.

Besides, it has the added benefit that if your neighbors get a little uppity, you let your mirrors slide a little off course and get a little more tightly focused ... bam, instant death ray. And, that's where the real money is. ;-)

Re:If you're just beaming it down to earth anyways

[mark-t]

I get how collecting energy in space can be more efficient than collecting it on the ground, but if you actually have to beam it down to earth in the first place, you are going to have to transmit it through the same atmosphere that would reflect and absorb so much of the sun's energy in the first place. Although I can see the theory of not having a night giving additional power, for everything else you are still ending up trying to collect energy on the ground from space, which seems fundamentally no different than collecting it from the sun directly.

Re:If you're just beaming it down to earth anyways

[CrimsonAvenger]

What's going to make collecting energy on the ground from a satellite more efficient than collecting it from the sun?

Without speaking to the economic feasibility of the idea in general, the advantages over a groundside installation are three-fold (or maybe 2.5-fold):

1) There's more solar radiation up there, since the atmosphere doesn't block it.

2) The sun doesn't set on the orbital installation nearly so often as on a ground station. A ground station has to deal with darkness half the time (more in winter, less in summer, of course), plus lessened efficiency early and late in the day, when the panels aren't aligned with the Sun. An orbital installation lose a few hours of daylight every six months at the equinox, and can remain aligned properly with the Sun at all times for maximum efficiency).

3) It takes up less of your limited real-estate to put the solar collector in orbit. Yes, you need a large area receiver on the ground, but, given microwave transmission from orbit, the area UNDER the receiver is still useful for farming, parks, that sort of thing (hell, people could live there safely, but the anti-solar-satellite whackjobs that WILL appear if someone tries this will scream to high heaven about the incredible dangers).

Re:If you're just beaming it down to earth anyways

[ubergeek2009]

The power will be transmitted as microwaves, which aren't scattered by the atmosphere as easily as visible light.

Re:If you're just beaming it down to earth anyways

[mark-t]

But for point 2, you are still having to ultimately try to collect that energy on the ground anyways. It would be fine for collecting energy in space that you were using in space, but if you are beaming it to the ground anyways, I really don't see a fundamental difference between that and just collecting it from the sun from the ground.

That said, I can see how it could provide almost 24 hour access to energy (point 1), although I'm not exactly sure that you'd really collect sigificantly more energy doing things that way than you would just collecting energy on the ground directly from the sun in the first place, since in both cases, you are still dealing with ground-based collectors... and although the space-based collectors might be very efficicent, unless they actually approached 100% efficiency, I'm not sure that after transmitting the energy to ground-based collectors on earth, you'd get anywhere close to twice the amount of energy out of them just because you happen to be able to collect energy any time of day or night.

Re:If you're just beaming it down to earth anyways

[Rockoon]

I really don't see a fundamental difference between that and just collecting it from the sun from the ground.

Why dont you? have you even considered how it would be transmitted? Apparently not, because you seem to think we will have a flashlight in space shining light on the earth.

Re:If you're just beaming it down to earth anyways

[DerekLyons]

A satellite in geosynchronous orbit is in daylight essentially 24/7/365. A solar panel on the ground.... isn't.

That being said, this is about as newsworthy as yet another Bennet Hazelton bloviation. Solar power sats have been spec'd out by any number of agencies or organizations with the engineering chops to do so, and they all come a cropper on the same issue - it's simply too goddam expensive to boost the satellite's components into orbit.* Even SpaceX's most fevered dreams of how low they can reduce the costs ends up being too expensive by a wide margin. Not to mention that even adding another 9 or two to the current dismal reliability** of space launchers not only vastly increases the cost, but due to the number of launches required still means you're almost certain to lose at least one of your payloads.

* No, building out asteroid or lunar mining technology isn't much help due to the immense cost of doing so.

** On average, somewhere between .94 and .96 for mature launchers.

Re:If you're just beaming it down to earth anyways

[mark-t]

Point 1 is moot.... since you are going to try to transmit the energy back down to earth anyways... The atmosphere is going to be just as effective at blocking the energy from the satellites as it is from the sun... possibly even moreso, since the satellites will not actually be transmitting as much energy as the sun can potentially provide.

Point 2 I can see the merit behind... but unless the satellites approach a hundred percent efficiency, I'm still not sure you'd see significant gains over collecting energy from the sun directly using ground-based collection.

For point 3, see point 1.... you still need ground-based collection anyways... unless you are only using the energy in space, it does not make any sense to expect transmitting the energy from a satellite to earth to somehow magically be more efficient or superior to collecting the energy from the sun directly using ground-based collection.

Re:If you're just beaming it down to earth anyways

[alexander_686]

Your point on base load is a bit off point. Base load is cheap because it uses coal or nuclear. If you want be to carbon neutral or want to close down all of your nuclear plants, those things go away so your cheap base load goes away. And as of today we don’t have any good way to store electricity generated during the day for night time use. Yes – I will acknowledge that there are some interesting projects out there, but nothing cheap enough for prime time today. This would be a solution – abet an exotic one.

Space is theoretically more efficient. Period. You don’t have an atmosphere absorbing the sunlight. You point out some practical issues but that does not detract that space is theoretically more efficient. Poke around the interesting and you can find plenty of interesting solutions. Some are table top demonstrators while others boarder on science fiction. But I will stand that on theory it is better. I can’t say if we can overcome the practical aspects.

On solar for the military, you have to deal with nighttime storage issues and operations during the winter where there is little sunlight. Space based would avoid these issues. Solar is not a slam dunk.

Does space based power have formidable challenges? Yes. Will it likely happen? No. However we should all have a soft spot for long term projects that try to hit a home run with creativity. As a reminder, today is DNA’s 61st birthday. Without some wild and crazy experiments we would never have found the double helix.

Re:If you're just beaming it down to earth anyways

[jellomizer]

First. You can put the satellite so it will always be facing the sun... However, you will need a strip of power receivers that strips across the world. otherwise you will get a large block of rock call the Earth getting in the way of beaming the energy. You may be able to store it then blast it out every day. However energy needs of the world require longer spread out energy. That is why we don't power stuff by lighting.

Second. When you beam the energy back, that energy is going to go threw clouds and weather, perhaps fry a bird or two. So a lot of that energy gained will be loss.

Third. The military isn't really a model of effective energy. They will sacrifice a lot of power efficiency if it gives them a tactical advantage.

Re:If you're just beaming it down to earth anyways

[alexander_686]

Sunlight is broad spectrum and some of it will be absorbed by the atmosphere, clouds, etc..

The idea is to shift the energy from a broad spectrum to a wavelength, like microwaves, which are not absorbed. In theory one can squeeze more energy out. Now, we are talking about sunlight => electricity => microwave output => microwave reception => electricity, so there are known issues that need to be resolved.

Re:If you're just beaming it down to earth anyways

[alexander_686]

First, geosynchronous orbit. It will always point to the same spot on earth. (There are issues – see the article for depth.)

Secondly, microwaves are not much affected by the atmosphere, clouds etc. I don’t think the odd bird would have much effect. Not saying there won’t be an effect on the bird.

Third - well yes. It is the Department of Defense and not the Department of Energy which is pursuing this in the US. What may be impractical for daily electric consumption may be practical on the battlefield..

Re:If you're just beaming it down to earth anyways

[i kan reed]

Or a network of satellites that can transmit to eachother, and the nearest ones transmit to ground.

Re:If you're just beaming it down to earth anyways

[mark-t]

The article.

Mirrors in orbit would reflect sunlight onto huge solar panels, and the resulting power would be beamed down to Earth.

Re:If you're just beaming it down to earth anyways

[CrimsonAvenger]

Nah, we can transmit down from the sat using a different part of the spectrum that the atmosphere is more transparent to.

As to the ground-based receptors - you can, for instance, block microwaves with a mesh that is mostly transparent to visible light. Which means a microwave receptor can be mostly transparent to visible light. Which allows you to use the land under the receptor (if you put it, say, ten feet off the ground) in pretty much any way you desire - grow wheat, corn, cows, etc.

Re:If you're just beaming it down to earth anyways

[Bengie]

I would not want to be a bird or in an airplane if I passed under this satellite. They'll have to make sure they have some really good fail-safes in place in case it pivots any. I've played SimCity 2000, I've seen what a microwave power plant can do.

Re:If you're just beaming it down to earth anyways

[MetricT]

It's not a completely stupid idea, just a mostly stupid idea.

But it might make financial sense for powering McMurdo Base, for instance. The cost of hauling diesel down there is almost as ludicrous. Remote outposts and stuff.

Or if your government decided to send a small team of special forces into hostile territory, that would be a convenient way to provide them power. And you could use "cheap solar power for everyone" as good cover for launching something.

Re:If you're just beaming it down to earth anyways

[kasperd]

If there exists an orbital path which can see the sun 24 hours/day, and that same orbital path lets you see the receiving stations, say, 18 hours/day

You can swap those and look for an orbit that can see the receiving station 24 hours/day and the sun more than 18 hours/day. Geostationary orbit would be an option covering both. To not have a period at night, during which you receive no power, you could have two satellites at different points in geostationary orbit pointed at the same receiving station. Then you will have two periods during the night where only one receive power, but you could position the satellites such that those periods happen when power usage is lowest. The tilt of the Earth's axis might even ensure that the problem of losing power at night is only an issue at certain times of the year.

I am just wondering when (if ever) geostationary orbit will get too crowded.

Re:If you're just beaming it down to earth anyways

[SailorSpork]

They had these in SimCity 2000. You built Microwave power collectors that collected energy from orbital space stations.

Why I'm bringing it up on Slashdot (aside from the hoped-for karma boost from invoking PC game nostalgia) is that occasional disasters happened if the orbital satellites were ever off by a fraction of a percent and they beamed the energy into the nearby residential population instead.

I'd be very interested to know more details of how they plan to transport the energy to the surface.

Re:If you're just beaming it down to earth anyways

[LifesABeach]

I know it sounds goofy, but has anyone thought of an Aeral Wire Tether? At least there's some support evidence using this.

Re:If you're just beaming it down to earth anyways

[Maury Markowitz]

> Base load is cheap because it uses coal or nuclear

Or wind, or hydro, or pumped storage, or tidal power or natural gas or geothermal or lots of things. Fallacy of the excluded middle.

Last night demand in Ontario dropped to 12.3 GW. That is less than the minimum amount of power the grid can generate. So in order to get rid of that power, they sold it for, literally, zero cents.

No one is going to build a device who's only selling point is that it produces more of this stuff.

> Space is theoretically more efficient. Period

The band gap of silicon solar cells is in the near IR, which means any light above that frequency is increasingly inefficient in capture. They capture less than 1/2 of the power from blue light, for instance. By down converting some of the light from higher frequencies, the atmosphere increases photocurrent. Typical cell designs are about 14% efficient in space and 16% on the surface.

> You don’t have an atmosphere absorbing the sunlight

That's not efficiency, that's photocurrent.

Re:If you're just beaming it down to earth anyways

[CrimsonAvenger]

the current dismal reliability** of space launchers

** On average, somewhere between .94 and .96 for mature launchers.

And yet the Shuttle program was shutdown with a 98+% reliability rating - two failures in 135 launches.

Which is why we've been hitching a ride with the Russians on the much more reliable Soyuz, which has had only two failures in 120 launches....

Re:If you're just beaming it down to earth anyways

[alexander_686]

I am missing your point. The article does mention using a tether to stabilize the solar array. Are you thinking about electric production? I can be used as such but unfortunately producing electricity robs one of delta, which drops your orbit – eventually into the atmosphere. There is no such thing as a free lunch. Most suggestions I have seen is to pump electricity into the tether to increase delta.

Re:If you're just beaming it down to earth anyways

[Maury Markowitz]

> Nah, we can transmit down from the sat using a different part of the spectrum that the atmosphere is more transparent to.

That's not what he's saying. He's saying that you're more efficiently transmitting a tiny amount of the available power, instead of less efficiently transmitting *all of it*. Unless you propose covering a patch of the sky the same area as the surface of the Earth facing the sun, it is unlikely you will be able to change this.

> Which allows you to use the land under the receptor (if you put it, say, ten feet off the ground) in pretty
> much any way you desire - grow wheat, corn, cows, etc

Which we do all the time with solar panels already. It's called "solar crop sharing" or "solar cropping". Actually, there's a good article on this in the sidebar of the JAXA article that is the basis for this post.

Re:If you're just beaming it down to earth anyways

[WillAffleckUW]

I know it sounds goofy, but has anyone thought of an Aeral Wire Tether? At least there's some support evidence using this.

Yes, I think al-Qaeda proposed that, as an interesting method of doing things.

Re:If you're just beaming it down to earth anyways

[R3d M3rcury]

Well, in Japan's case, you have the problem where there isn't much ground to collect energy from. Sure, here in the US, we have great big wide open spaces where we could put solar collectors.

And we'd really rather that they not start trying to collect more land...

Re:If you're just beaming it down to earth anyways

[cpaalman]

>> So I guess the design of a fail-safe, automatically self-repairing.......

So I guess you didn't RTFA did ya now?

>> Oh sorry, so you'd be scheduling regular maintenance and repair trips? In geostationary........

Oh sorry, you couldn't be bothered to RTFA to answer your silly questions?

>> One tiny little question, the light pressure on this giant solar array, how will it be.......

One tiny little question, did ya RTFA?

>> Wait, something so large and thin would......

Wait, something so easy as RTFA is too challenging, but spouting off about engineering issues, to which I'm sure you are an expert, not so much.... Hmmm!

>> But isn't the Earth under imminent threat of being wiped out by the......

But isn't Earth under imminent threat from ignorant people who don't RTFA before spouting off??

Re:If you're just beaming it down to earth anyways

[Pinky's Brain]

Plenty of ocean though ...

Re:If you're just beaming it down to earth anyways

[Whorhay]

The solar cell problem with efficiency sounds like an issue that might be better addressed by just not using solar cells to directly generate current. How about instead of hoisting heavy PV cells we put up a mirror array built of very thin foil. Arrange the mirrors to direct the light onto a working fluid and generate power using that? The only downside I can think of to that at the moment would be that the mirrors would have to be mechanized to track the sun.

Re:If you're just beaming it down to earth anyways

[Amtrak]

From a Military perspective how to do you keep someone from just shooting down your space based solar array. It's pretty hard to stop a high velocity missile from impacting and destroying a large stationary object this is pretty fragile. I guess you could arm the array with lasers, guns, missiles and such and hope to detect and change the vector of an approaching impactor but that sounds expensive and probably in violation of our no space based weapons treaties. Though the whole array could probably be turned into a weapon so it might be out just by itself. Not saying we shouldn't build one though just fun to think about that.

Re:If you're just beaming it down to earth anyways

[FishTankX]

First off, Japan is space starved and property prices around it's population centers is staggering. Also, 80% of the country is mountainous.

Second of all, the irradiation in space is higher, about 1.3kw per square meter vs 1kw at the equator.

If you count in the fact that the sun is shining 24 hours a day 365 days a year.. versus the estimated 6 hours a day of good sunshine down on earth, you end up with roughly 5x the light per square meter of collector per hour per day averaged.

There's also no dust to mire the panels in space, or atleast not dust as we know it on earth. And if concentrating solar is used, like in the mirror design, high efficency solar panels can be used, again resulting in a 1.5x-2x boost in efficency per square meter of collector.

Cost wise though it'd probably be cheaper to fill every house's roof with solar panels, before going the space based route first. Economics is likely to be much better, unless they find a way to launch massive unfurling mylar mirrors into space, get them to play nice, and do it cheaply.

This all being said, if there's any way you could use local asteroids to start fabricating SPS's in orbit, then the economics change entirely and it's not so easy to say how it will play out.

Re:If you're just beaming it down to earth anyways

[FishTankX]

I believe the key difference here is that the soyuz space capsule hasn't killed anyone in 43 years. Which is mildly less impressive than the japanese shinkansen's no passenger fatality record. But more impressive than the shuttle's recent track record.

Re:If you're just beaming it down to earth anyways

[alexander_686]

There are only 3 countries that can shoot down satellites today, the US, China, and Russia. So maybe not against those. I am sure that others could follow suite, but it is going to be a long time before insurgents, irregulars, etc. could do it.

Re:If you're just beaming it down to earth anyways

[Anonymous Coward]

To me, the best reason to do this is to power things *in space*. Right now, many space satellites are powered by batteries charged by solar panels. What if you could "offload" the panels to a single facility that beamed the power to the individual satellites (perhaps on demand, for brief periods of time, to charge internal batteries)? Well, it would allow you to build one big solar cell "facility" instead of many small ones on all of the individual satellites...perhaps it would make them somewhat cheaper to construct/deploy without those large solar arrays hanging off.

Re:If you're just beaming it down to earth anyways

[mark-t]

I'm not contesing the notion that collecting energy in space is more efficient or that it would save real-estate, or avoid a lot of the problems you find with ground-based collection, but unless you are intending on actually *using* that energy in space, you are still going to have to beam it down to earth in some form. That is going to require ground-based collectors that will use no less real estate than solar collectors, and you'll be dealing with atmospheric efficiency losses anyways. Plus, you'll only be transmitting *some* of the energy that the sun provided... since the satellite's efficiency is not likely to be anywhere near a hundred percent. All of the additional hours of energy availability that you get from having a collector in space may simply not actually be worth it.

Re:If you're just beaming it down to earth anyways

[LordLimecat]

Actually, the opposite is true. Cells, silicon ones anyway, are more efficient under the air. It has to do with their band gap.

You're gonna have to explain this more. The atmosphere filters out a good chunk of the spectrum we receive from the sun; if there were truly some benefit to said filtering (which is very suspect) we could simply place a filter in front of the cells.

Re:If you're just beaming it down to earth anyways

[NeoNormal]

a new idea

Sorry, you lost me there.

Re:If you're just beaming it down to earth anyways

[Beck_Neard]

Actually this has been studied and in the most realistic scenario the density of the microwaves will be so diffuse that a bird could fly through without noticing anything but a slight warming, similar to how sunlight warms you up. In fact, due to the pleasant warmth the beam produces, a significant problem would be keeping cold birds in winter out of the beam!

Of course prolonged exposure to microwaves wouldn't be nice and could cause all sorts of internal organ problems, if you were standing directly under it for a significant period of time.

Re:If you're just beaming it down to earth anyways

[blue trane]

Using economics to bash basic science research is ridiculously short-sighted. AT&T refused at first to invest in internet research, because their business model was based on telephones. Business is okay at incremental innovations (making computers smaller), but not at disruptive innovations (making computers in the first place). Research such as this has to be publicly financed, precisely because market signals are too short-sighted and profit-oriented to invest in it.

Re:If you're just beaming it down to earth anyways

[Guspaz]

Errm, it's not short-sighted if the economics will NEVER be feasible. Launch prices will never be low enough that it will be cheaper to put solar panels in orbit and transmit power back to earth, rather than just putting more solar panels (and batteries) on earth in the first place. To do that today, you'd need launch prices that are something like $10 per pound. Even SpaceX is only selling at about $1000 per pound, and even their pie-in-the-sky figures for fully reusable vehicles in the distant future only have them going down to $100 per pound. On top of that, solar panels will continue to get cheaper, meaning that the breakeven point on launch prices will keep dropping (far faster than the prices themselves will drop).

Spending money on orbital power (today OR tomorrow) is basically like saying we should replace power transmission lines with people carrying AA batteries walking hundreds of kilometres by foot because it would be cheaper if only hourly wages would drop low enough.

Re:If you're just beaming it down to earth anyways

[HornWumpus]

So has anybody been able to identify the box with the cell phone in it, double blind?

Last I heard the EMF idiots were bragging about getting almost 50% right (when 1 in 2 had an active cell phone in it).

Re:If you're just beaming it down to earth anyways

[blue trane]

I think your "never" is really saying that you don't have the imagination or technical know-how to do it.

Space elevators, for example, could bring down prices. When computers were first invented, who foresaw Moore's law? Yet government investment in the chips that TI produced kept the private sector afloat.

In conclusion, try to think beyond next quarter's shareholder report.

Re:If you're just beaming it down to earth anyways

[HornWumpus]

New to him.

His mother must have bought his /. account for him, for bragging rights.

Re:If you're just beaming it down to earth anyways

[Guspaz]

Those are the only thee countries that *HAVE* shot down satellites. In practice, there are others that have the capability. There are other nations with ICBMs and orbital launch capability... and some of those countries are enemies of the US.

Re:If you're just beaming it down to earth anyways

[Grishnakh]

I'm surprised this is being asked on a "news for nerds" site.

1) In orbit, there's no attenuation of solar energy. On the ground, you have attenuation from the atmosphere, plus the whole problem of there not being any sunlight at night. It's worse in Japan; that country isn't exactly famous for being sunny, despite the flag. It has a high latitude and is pretty rainy as I recall.

2) Japan doesn't have a lot of open area to set up solar panels. Collecting it in orbit and beaming it in concentrated form to Japan is probably more feasible and efficient than trying to cover every building in Japan with PV panels.

Re:If you're just beaming it down to earth anyways

[LifesABeach]

Your thoughts would make more sense if you had posted as an AC

Re:If you're just beaming it down to earth anyways

[newcastlejon]

bloviation

I like that. My new word for the day.

Re:If you're just beaming it down to earth anyways

[Guspaz]

Space elevators are cheap, but they're not free. They'll be very expensive to build, and will only be able to move so much mass at a time, which will result in them having a not insignificant cost to get stuff to GEO. By the time they're practical, the cost of PV panels will have dropped so much that it still will be cheaper to just build more PV panels on earth rather than loft them into orbit on a space elevator.

PV prices are dropping faster than launch prices. You'd need launch prices that are something like $10 per pound (two orders of magnitude cheaper than today) to make orbital power feasible with today's panels, but by the time launch prices dropped that low (if they ever do), PV panels would be that much more efficient, and you'd need launch prices much cheaper than $10 per pound.

Re:If you're just beaming it down to earth anyways

[Teancum]

Plenty of ocean though ...

.... that you can fill with algae and harvest much faster and easier than solar farms not to mention the algae also provide their own energy storage. The algae also can be converted into hydrocarbon chains..... that can in turn make gasoline and other petroleum-based products and fit into the existing energy distribution channels.

Re:If you're just beaming it down to earth anyways

[Mr D from 63]

Isn't there a bit of irony in the idea, in a time of global warming attributed to greenhouse capture of solar heat, to capture even more solar energy and send it to earth? A large amount of that energy will be dissipated as heat eventually.

In the end, it seems like a cost prohibitive pipe dream.

Re:If you're just beaming it down to earth anyways

[nospam007]

"Which is, of course, utterly wiped out by the cost of launch. And everyone knows this."

Beats guarding nuclear ashes for 200.000 years.

Re:If you're just beaming it down to earth anyways

[Guspaz]

What, me? I don't get why people think space elevators will be practically free to use. If you spend tens of billions of dollars building something, you can't then claim that it has a zero dollar per kilogram cost for lifting payload.

Some estimates seem to put them at a hundred bucks a kilo. That's quite good, but it's also in the range of where reusable rockets might get, so it's not magical.

Re:If you're just beaming it down to earth anyways

[nospam007]

"But it might make financial sense for powering McMurdo Base, for instance. The cost of hauling diesel down there is almost as ludicrous. Remote outposts and stuff."

You could just use some of the microwave to heat up the surroundings of McMurdo Base to a cozy temperature.

Re:If you're just beaming it down to earth anyways

[alexander_686]

We are talking about geosynch – a very high orbit. That cuts out many space faring states. I can’t think of any American enemies that can get there – only friendlies and neutrals. Who are you thinking of?

And of course getting to space is only half the trick – you then need to guide your missile. Guidance is hard.

Re:If you're just beaming it down to earth anyways

[mark-t]

1) In orbit, there's no attenuation of solar energy. On the ground, you have attenuation from the atmosphere,

I get that.... but unless you are just going to be using the energy *in* space, you are going to have to beam the energy to earth from orbit anyways, and so you're still dealing with atmospheric losses. You might get less losses with microwaves than you do with higher frequency radiation, but it's still going to exist... and unless the efficiency of conversion from solar energy to microwaves approaches 100%, I can't see it offering a significant savings.

2) Japan doesn't have a lot of open area to set up solar panels. Collecting it in orbit and beaming it in concentrated form to Japan is probably more feasible and efficient than trying to cover every building in Japan with PV panels.

Sure... but then how do you use the energy you've collected in space without building collectors on the ground anyways? Collectors that will take at least as much space as solar panels .

Collecting energy in space is fine for using the energy *IN* space... but as soon as you add the notion of transmitting it to earth, you are going to be dealing with most (but not all) of the same problems that you would be just trying to collect solar energy directly from the ground. The only significant difference is that you can collect energy from a geosync satellite almost 24/7/365 (with up to about 75 minutes or so of darkness every night for a period of about 8 weeks in the time surrounding the spring and autumn equinoxes). But in practice, I'm not so sure it would really be significantly better than using ground-based systems because of the other factors.

Re:If you're just beaming it down to earth anyways

[blue trane]

There are other reasons besides economics to build solar collectors in space. The kind of feudal economics you're locked into can't account for new innovation that would make it better to have solar farms in space. For example: space colonies.

It's also environmentally better to build energy plants in space. I've seen solar farms in the desert in Arizona. Some of them keep the ground cover but others pave it over. Where do the lizards go?

The goal should be to get Earth back down to about 500 million people, and let the environment regenerate, not pave over the remaining land.

Re:If you're just beaming it down to earth anyways

[HiThere]

In addition to the other answers, you would need to choose a wavelength that wasn't absorbed by clouds, fog, rain, or snow anyway, so you'd probably choose wavelength that wouldn't be absorbed by anything small. Most proposals I've seen call for antennas a mile or more in diameter. As such, small things like animals or airplanes shouldn't receive any noticible amount of power.

Re:If you're just beaming it down to earth anyways

[HiThere]

Well, it's not just a different wavelength, it's also much more directed. (Not THAT directed, as you don't want a wavelength that gets absorbed by water, and longer wavelengths aren't as directional, but still a lot more directional than just shining a light.) IIRC there's a corner reflector on the moon, placed there by one of the Apollo missions, that people have repeatedly bounced microwaves off of and caught the reflection that bounced back. So it's fairly directional.

Re:If you're just beaming it down to earth anyways

[rahvin112]

Space based panels are routinely more efficient than earth based ones, mostly because they spend the bucks to get the best possible efficiency. IIRC space based panels are right around 30% efficient while the best earth based panels on the commerical market are low 20's with the majority sold in the 8-15% range. Afteral if you are going to pay $20K a pound you might as well send up the best money can buy.

The atmosphere bounces a lot of energy, and some entire areas of spectrum are bounced nearly completely (such as the ozone layer bouncing much of the UV radiation). In theory (we don't have the technology yet) you could layer transparent panels tuned to certain spectrum, ie have a UV panel that bleeds off all the UV energy, then move down the spectrum sucking off each wavelength with tuned panels. In such a situation you could extract massive amounts of energy per square meter because your efficiencies could be near theoretical maximums. There is no question such a scenario would require massive arrays of solar panels. Your typical communication satellite (modern) use about 10KW of electricity and has a huge panel span. DirecTV-12, uses 8.9KW, and has a "wing" span of 158 feet tip to tip of solar panels. To generate the power needed for a city you'd need a bird a kilometer wide and high and it would cost billions to put it all in orbit.

Re:If you're just beaming it down to earth anyways

[Guspaz]

I will jokingly point out that the main political source of strife that basically starts a world war in the Japanese animated series "Gundam 00" was the existence of orbital solar power plants, and how they concentrated wealth in the hands of a few rich countries after oil became scarce :P

Space colonies would certainly do well to rely on solar power, but it's not clear why a solar power plant would be required for them when they're already in space and could use their own solar power. I'm not saying that solar in space serves no purpose, far from it. I'm saying that the net benefits of orbital solar power with the goal of delivery to earth will never pay off for mass power distribution. There may be some isolated use cases where the benefits might outweigh the costs (perhaps military use), but it'll never be more affordable than ground-based solar.

Re:If you're just beaming it down to earth anyways

[Pinky's Brain]

You need bioreactors for that (ocean water is not very nutritious). PV + power to gas seems to me the best approach.

Re:If you're just beaming it down to earth anyways

[Blaskowicz]

Last night demand in Ontario dropped to 12.3 GW. That is less than the minimum amount of power the grid can generate. So in order to get rid of that power, they sold it for, literally, zero cents.

No one is going to build a device who's only selling point is that it produces more of this stuff.

This is a problem posed by terrestrial solar and wind, mainly : they generate power when they feel like and regardless of any demand for it. Wind is worst in this regard, able to provide near full or near zero power on a random basis and is thus completely not base load at all.
Space based solar would would pretty constant, and thus would be base load - similar to nuclear which is nearly always-on base load. So space solar would reduce that problem, vis-a-vis intermittent sources which make it worse. (ideally you have base load you can modulate, nat gas and hydro can do that ; coal does with a lot more inertia. France went for developing the very limited ability of nuclear to modulate production but that doesn't get you very far)

Of course that doesn't mean I think space based solar is a realistic or worthy idea. I would settle for a panacean energy storage made of nanotech pixie dust, if we're allowed to wish for things that don't exist.

Re:If you're just beaming it down to earth anyways

[Blaskowicz]

You need to send a small possibly inert payload that crosses the solar station's path, not achieve any meaningful orbit. Anything colliding with the station will seriously mess it up.
USSR sent a Moon impactor on a Soyouz rocket variant in 1959 so it seems hitting stuff with hardware made for LEO capability is possible. The Moon is of course a target a tad bigger than a satellite, even if the satellite in question would be much bigger than the ISS so I agree about the guidance part.

Re:If you're just beaming it down to earth anyways

[DerekLyons]

And yet the Shuttle program was shutdown with a 98+% reliability rating - two failures in 135 launches.

Which is why we've been hitching a ride with the Russians on the much more reliable Soyuz, which has had only two failures in 120 launches....

Only two failures if you only count the Soyuz booster failures. When you add in the multiple failures of the Soyuz spacecraft.... the picture isn't quite so rosy.

But yeah, the Soyuz isn't all that different in reliability from Shuttle. That's the great paradox that the capsule cabal and "cheap+simple=safe" cadets won't recognize.

Re:If you're just beaming it down to earth anyways

[DerekLyons]

I had odd parents - my dad actually got pissed if I used a nickle word when there was a more correct or descriptive dollar word available.

Re:If you're just beaming it down to earth anyways

[HornWumpus]

Pumped storage takes baseload, it doesn't supply it.

Re:If you're just beaming it down to earth anyways

[AmiMoJo]

Baseload power is currently selling for 2 to 3 cents, peak power is up into the 20's. No one is going to build a space-o device to provide something we have trouble giving away.

In the US, which produces lots of dirty power to provide baseload. In Japan it is much more expensive already, and they give a shit about being clean. Japan turned out to be unsuitable for nuclear power, so an alternative is required. At the moment it is looking like in the long term it will be battery backed wind and solar, with geothermal and some coal/gas. Hopefully by 2030 SPS will be an option too.

Re:If you're just beaming it down to earth anyways

[AmiMoJo]

The plan is to place it in geosynchronous orbit, with steerable mirrors to focus sunlight onto the panels 24/7.

Re:If you're just beaming it down to earth anyways

[Grishnakh]

Sure... but then how do you use the energy you've collected in space without building collectors on the ground anyways? Collectors that will take at least as much space as solar panels .

The energy is more concentrated, probably in a MASER beam. You don't need nearly as much area.

Re:If you're just beaming it down to earth anyways

[alexander_686]

We actually have multi layered technology today. They figured out how to do it in the last year or so. I don't think they have done commercial production yet.

http://www.economist.com/news/...

Re:If you're just beaming it down to earth anyways

[mark-t]

You realize that such a beam, if sufficiently concentrated, could be positively catastrophic for anything to fly through, right? It's equally problematic for anyone living nearby if the aiming system on the satellite drifts by even the smallest amount, given the distance of transmission.

But hey... if you want something with obvious military application, just say so. Don't disguise it as something that's supposed to be used for an allegedly peaceful activity like power generation.

Also, even microwaves have some efficiency loss in transmission, and in particular can be heavily affected by things like rainclouds unless you propose having the thing be so powerful that it will basically cook anything that happens to be at higher altitudes, which could introduce additional efficiency losses as it superheats water vapor in the upper atmosphere.

Re:If you're just beaming it down to earth anyways

[mark-t]

no one's colonizing Mars and no one's mining asteroids. Ever.

Unless you believe the human race is going to be wiped out by some catastrophe, and are interested in being accurate, you should probably replace "ever" with "in the foreseeable future". Otherwise, all you're saying is that something won't ever happen which actually *COULD* happen someday, but will not happen for so sufficiently long from now that nobody in that future would ever hold it against you for believing that it never would.

That doesn't make you right, however.

Re:If you're just beaming it down to earth anyways

[eric_harris_76]

Construction in orbit would eliminate the cost of launch. And that would require a functioning space-faring economy capable of creating such a thing.

When satellites go into geosynchronous orbit from their manufacturers from _above_, the economics may be different. Maybe. Even so, it could be a long long wait.

But I thought we were in for a long long wait for the Iron Curtain to come down, so what do I know?

Re:If you're just beaming it down to earth anyways

[Jefftoe]

Nikola Tesla call your office. lol

Re:If you're just beaming it down to earth anyways

[blue trane]

But relying on the private sector to research innovative alternative energy sources (as the original post I was replying to in this thread implied) is futile. Did the private sector build Hoover Dam? When oil dropped to $10/barrel during the 1990s, the private sector abandoned alternative energy research. That was precisely the time when government should have invested in it (but Reagan's influence in defunding the DOE's alternative energy projects prevailed, a continuation of his attitude of symbolically ripping out the solar panels on the White House that Carter had installed). What the private sector considers uneconomic may be good for the General Welfare, and then government should fund it, by borrowing from the Fed at zero cost for example.

Re:If you're just beaming it down to earth anyways

[Keith Henson]

Let's take a crack at putting numbers on your assumptions.

Assuming power satellite people want a large market share, they will have to set the cost lower than other sources. Say 2 cents per kWh. Hydro is lower, but there isn't enough of it.

If you go into the models for calculating levelized power, then to get 2 cents per kWh, the cost of the source can't be higher than $1600/kW (6.8% discount and 20 years). Even in China nuclear reactors are about $5000/kW. Ground PV can't get close, it might hit 8-10 cents per kWh, but at that cost the concrete and steel become bigger factors than the silicon.

The rectenna, the part on earth, will cost around a billion dollars for 5 GW. That's $200/kW. I have published the details on how I estimated the cost, can quote them if you want.

I favor thermal designs as they are a lot smaller, but even with PV, it should be possible to get the cost of panels and transmitter plus labor down around $900/kW referenced to the output of the rectenna. That's assuming microwave amplifier tubes cost about the same per kW as they do in microwave ovens.

So a reasonable cost for power satellites $200 plus $900 plus $500 for the transport to GEO.

I think it's reasonable to expect power satellites to mass around 5 kg/kW.

Thus the allowed transport cost to GEO is $100/kg, or $45/lb. But that's to GEO, not LEO.

Re:If you're just beaming it down to earth anyways

[nobodie]

Also, the weather in Japan is often not conducive to gathering solar. One other thing worth mentioning: no earthquake or tsunami in space. You pshaw, but think about this Americans: all those stupid poles we put up for power lines to supply electricity to our homes and offices. When the weather turns bad we lose power because of the poles, not because "the weather is bad so we lose power." If we had our power lines underground then the weather would have almost no effect on the power supply.
Apply that to the earthquake/tsunami/any ground based power equation and long term costs change in what might be interesting ways.

Re:If you're just beaming it down to earth anyways

[rahvin112]

I saw the announcement when it was made, the efficiencies were ridiculously low, like 1-3%. That's not viable. We're a long ways off yet.

Sounds a little scary

[mi]

From TFA:

Several giant solar collectors in geosynchronous orbit are beaming microwaves down to the island from 36 000 km above Earth.

What if they miss the aim one day by half a degree — the beam hits outside of whatever is supposed to process it dirtside? What will the effect be — and how far away must that island be located for reasonable level of safety?

Re:Sounds a little scary

[Virtucon]

Not as scary as Godzilla.

How is it beamed down again

[Anonymous Coward]

Oh yeah, microwave. Nice, a high energy microwave death ray in space. Good idea.

Re:How is it beamed down again

[lister king of smeg]

Really they don't plan to use it a giant space based death that could easily be pointed at North Korea, Shanghai, no its just to beam a metric shit-ton of power to them really, oh the on board missiles and armor plating are just there to keep the space junk from breaking it.

Not going to happen

[Maury Markowitz]

The numbers don't work. Period.

http://matter2energy.wordpress.com/2012/03/17/the-maury-equation-redux/

Re:Not going to happen

[rsborg]

The numbers don't work. Period.

http://matter2energy.wordpress.com/2012/03/17/the-maury-equation-redux/

So you're assuming this isn't a weapons platform? I mean, there aren't any real strategic benefits to being on the top of a gravity well, are there [1]?

[1] http://en.wikipedia.org/wiki/T...

Re:Not going to happen

[phillk6751]

Oops my bad...i should have RTFA...i saw the pic and thought they'd be reflecting light....this idea probably wouldn't work....wow

Re:Not going to happen

[rasmusbr]

When you consider the energy cost of launching the equipment into space (0.5*mass*speed^2) you also find that the system is possibly an energy sink depending on how heavy the equipment is and how efficient your space launch system is. You'd basically need a really good and optimized space elevator to even have a chance at having an energy source.

Every penny of space research that isn't spent towards making space launch cheaper and more efficient should be looked at with some suspicion.

Re:Not going to happen

[Maury Markowitz]

> Oops my badi should have RTFA...i saw the pic and thought they'd be reflecting light

No, you're right, that's definitely what the image implies.

As to the concept of using mirrors, some points

One is that conventional cells max out at about 1.1 "suns", meaning that if you shine more than another 10% light on them you flatline the power. It has to do with the speed of the charge carriers, they can only move so fast and after you get to some point where the incoming photo creates an electron that immediately hits a hole from the last photon.

But that said, you can still double the total production because you can get sunlight at night. Actually it's more like 4 times because you can dispense with the "trackers" on the ground and use fixed-mount panels, which saves a whole lot of money and space. So personally, I'm more than a little surprised this isn't the path people are exploring.

Re:Not going to happen

[bsolar]

Can't you "disperse" the concentrated light on more panels once it reaches the ground station to avoid the 1.1 "suns" limit? Another way might be to avoid photovoltaic panels and use the concentrated light to boil water.

Re:Not going to happen

[Maury Markowitz]

> The Japanese don't have a Nevada to put vast solar arrays into

It is important to note that the safely limits for microwave radiation is about 10 mW/cm^2. It is widely assumed that this number would be increased for a SPS system, and the baseline figure is 23 mW/cm^2. That compares to about 90 to 110 mW/cm^2 for "bright direct sunlight" under AM1.5 to AM1 conditions.

Let's examine the numbers. The article speaks of a collector "3 kilometres long". Let's assume, for the math, that this is the diameter of a circular collector, so that would be pi x 1500^2, or about 7 million square meters. In Japan, which is just about exactly AM1.5, that's 900 W/m^2, so that's 6.3 GW of power falling in that area. If covered with conventional panels with an arial efficiency of 16%, which is common these days, then this array using ground-mounted panels would generate 1.8 GW of power.

Now how much power is their design supposed to generate? 1 GW.

So you see the problem Now admittedly the *daily* energy produced would be about 24 GWh for the SPS and about 10 to 16 GWh for the solar panels (the upper limit assumes trackers). But I think you will agree that the small increase in size needed to cover that gap in total production, assuming you even want that (no one wants power at night, we're sleeping) is never ever ever ever going to cost less than the satellite. Even in Tokyo!

> but the energy received from the sun in space is stronger before it is weakened by passing through the atmosphere

About 25%, which is mostly reflection and scattering. Some of that you get back as diffuse blue-sky radiation. Overall it's much smaller than you might think - you can see the sun after all, think about what that actually means. Offsetting this is the drop in efficiency of the cells due to the spectrum, which is from 16 to 14%. This makes up a good chunk of what's left. In the end, it's pretty much a wash, maybe a few percent, at best.

> Your Insolation numbers seem to indicate a 6 hour day on earth with a 24 hour day in space

Those numbers include EVERYTHING. And I mean EVERYTHING, I mean everything from direct sunlight to diffuse sunlight to reflections off snow to dust on the panels to clouds in the sky to whether or not its cloudier in the morning or afternoon where you live to losses in the wiring to reflections off the glass on the front. If you can think of a loss mechanism, its accounted for in there.

> the mirrors wouldn't degrade at the rate the panels do

Go read the wiki article on space debris (which I basically wrote) and look at some of the images. Are you still so sure?

Trust me, I've looked at this issue six ways to Sunday. It cannot possibly work.

Re:Not going to happen

[LordLimecat]

The obvious question is "Why", and that post doesnt really explain its numbers well (though it does some linking). I mean, the equations indicate 40 year lifespan on earth vs 12 in space, but dont give a "why", so Id like to clarify for anyone who is as curious as I was.

The obvious assumption is that earth would be less friendly than space-- you have dust, the atmosphere, weather, etc to deal with, none of which exist in space.

Apparently the missing factor is solar radiation (ironically); apparently solar flares and similar events are very nasty for solar cells and knock huge chunks out of their life-- one of the linked pages indicates that single solar flares can knock 3-6 years off of a cell's lifespan. So the net result is that while you can get ~3x more raw "input" at the solar cell, you have to deal with a livespan roughly 1/3 that of a similar cell on earth and get two multiplicative transmission losses (space to ground, and ground to grid) on top of it.

The only gripe I have with the article you linked is that the transmission losses seem a bit high for the wireless transmission. However, its a moot point-- if you're losing all of your gains to lowered longevity, and you have to transmit twice, it would be virtually impossible no matter how good your wireless transmission was to beat the single transmission loss for ground-based.

Re:Not going to happen

[SethJohnson]

Two years ago, Obayashi corp announced its intention to have a space elevator up by 2050. Part of that design involves solar panels transmitting energy back down to terra firma.

Re:Not going to happen

[Maury Markowitz]

> Can't you "disperse" the concentrated light on more panels

Sure, but if you're going to shine 1 sun worth of light on the panels, why not just let the sun do it?

> Another way might be to avoid photovoltaic panels and use the concentrated light to boil water

Heat engines of this sort normally max out at about 40%, but given all the losses in this system that's likely not bad at all. There must be something I'm missing about using mirrors, I'll have to look into it more.

Re:Not going to happen

[Maury Markowitz]

> I may be an anonymous coward but at least my opinion isn't click bait

Mine's math. Try it some time.

Re:Not going to happen

[Maury Markowitz]

> the transmission losses seem a bit high for the wireless transmission

Friis transmission equation. I put the actual numbers in one of the other articles.

Re:Not going to happen

[jafac]

A method for working this out, in the 1970's, included a moon-base, and a mass-driver to launch raw materials into earth orbit for processing and construction. This was deemed to be profitable (by the precursors of what later become the Planetary Society, used to be the L5 Society) - based on projected energy costs (in 1973, during the energy crisis), and also based on a cheap, reusable spacelaunch system which would reduce launch costs to something like $10/kg. The Space Shuttle was supposed to BE that launch system, and we all know how that turned out. (nowhere near $10/kg).

So if you use today's numbers, and rule-out a moon-mining colony; yeah, it's kind of a ridiculous proposition.

However, a lot could happen to our energy costs in the not-too-distant future. Though I don't think that that will lead to orbital solar power stations.

Re:Not going to happen

[jafac]

If one could offshore a wind-farm, it seems trivial by comparison to offshore the receiving antenna.

Re:Not going to happen

[LordLimecat]

Can you give a clarification on any what level of expertise you are claiming in this field? I searched both on google and your blog, but found nothing. Its fine to make a statement of fact backed by numbers, but a number of things on your "Maurys Equation" article were really suspect, including a number of errors.

None of it changes the generally fine-sounding conclusion that solar in space is going to have really limited applications, and probably isnt suitable for mass market energy generation. But youre making a lot of points that border on "original research" (for instance, the wireless transmission paper that you linked to was showing ~80+% efficiencies as far as I could tell, and I could find nowhere in there that indicated the 50% efficiency you ended up with). It also makes me uneasy when someone with no apparent credentials claims to have an easy answer for why a group of industry professionals dont know what theyre doing.

Re:Not going to happen

[HiThere]

The article states that what they are transmitting down is microwaves. (If it were light, I'd believe it was intended as a weapon.)

FWIW, what I often imagine is using a sterling heat engine, but I believe that the cooling cycle would be too slow to make that practical...still, if you could make it work, perhaps at a high enough temperature (and a different working fluid...sodium?) then heating it with mirrors would be plausible.

Re:Not going to happen

[HiThere]

Moon mining isn't the only option. Currently there are groups planning on capturing an asteroid. And there are other possibilities. But it doesn't look too good with a straightforward approach.

Re:Not going to happen

[HornWumpus]

/. user HornWumpus announced his intention to do Natalie Portman and Jessica Alba at the same time...

Re:Not going to happen

[AmiMoJo]

Your mistake is making assumptions based on current technology. JAXA are using numbers based on future improvements in solar PV and microwave power technology. It's even mentioned in TFA:

In lab conditions, researchers have achieved about 80 percent efficiency in that power conversion on both ends.

(for microwave transmission)

The point of the system is to provide reliable base load power as a supplement to ground based solar. As surprising as this may be the clever folks at JAXA have actually done their sums and figured out how to make this work, even if armchair critics such as yourself can't quite grasp it.

Re:Not going to happen

[HornWumpus]

How they did their sums: Total of government grants greater then total cost of of hookers and blow for researchers.

Re:Not going to happen

[SethJohnson]

The optimist in me hopes HornWumpus accomplishes his goal atop the Oyabashi space elevator.

Japan might need to

[bigpat]

If Japan wants to move away from nuclear power, then space based solar might be the only alternative. Reliance on foreign oil has been a big drain on their economy since shutting down their nuclear power plants after the 2011 Tohoku earthquake and tsunami. The tension with China over the senkaku could be a direct result of increasing pressure to do oil and gas exploration in the surrounding waters. Regardless of Global Climate Change because of burning fossil fuels, we would all be better off if Japan could move away from fossil fuels, either back to nuclear and/or with more geothermal and even space based solar.

Re:Japan might need to

[HiThere]

It's not the only choice, but most of their choices are speculative. Tide motors, e.g.

I don't know how well solar cells would work in Japan. Southern Japan gets a lot of sunshine, but Japan extends a long way to the North. Hokkaido is rather chilly, and might be like Maine as far as solar cells were concerned. Which would mean no power during snow stormes.

Only six challenges to build an SPS?

[Ihlosi]

What about "Not having the thing clobbered by space junk"?

SimCity 2000?

[VorpalRodent]

If there's anything I've learned from video games, it's that this is a bad idea.

Corn fields?

[Hamsterdan]

Just imagine if they aim that thing at corn fields? I can see the headlines, major city destroyed by popcorn tsunami...

How Japan Plans To Build ...

[jeff13]

How Japan Plans To Build Orbital Solar Power Stations?

With giant freakin' robots! Obviously.

They should put it at L5

[karlandtanya]

Words: Bill Higgins and Barry Gehm c. 1978
Music: "Home on the Range"

Oh, give me a locus where the gravitons focus
And the three-body problem is solved,
Where the microwaves play down at three degrees K
And the cold virus never evolved.

CHORUS: Home, home on LaGrange,
Where the space debris always collects.
We possess, so it seems, two of man's greatest dreams:
Solar power and zero-gee sex.

We eat algae pie, our vacuum is high,
Our ball bearings are perfectly round.
Our horizon is curved, our warheads are MIRVed,
And a kilogram weighs half a pound. CHORUS

You don't need no oil, nor a tokamak coil,
Solar stations provide Earth with juice.
Power beams are sublime, so nobody will mind
If we cook an occasional goose.

INTERLUDE (to Oh, What A Beautiful Morning)
All the cattle are standing like statues.
All the cattle are standing like statues.
They smell of roast beef every time I ride by,
And the hawks and the falcons are dropping like flies...

I've been feeling quite blue since the crystals I grew
Became too big to fit through the door.
But from slices I sold, Hewlett-Packard, I'm told,
Made a chip that was seven foot four. CHORUS

If we run out of space for our burgeoning race
No more Lebensraum left for the Mensch,
When we're ready to start, we can take Mars apart
If we just find a big enough wrench. CHORUS

I'm sick of this place, it's just McDonald's in space
And living up here is a bore.
Tell the shiggies "Don't cry," they can kiss me goodby,
'Cause I'm moving next week to L4!

Re:But what does an actual physicist think?

[Virtucon]

While I agree with your comments I do have to point out that it's nice to set goals and to think out of the box when it comes to new ideas. Back in the 1960s we had this President that set a goal for the US in reaching the Moon, which we did. People need goals and objectives to strive for otherwise they become hopeless derelicts like Cliven Bundy.

Energy and materials cost

[WillAffleckUW]

The problem is that solar is really cheap.

Really really cheap.

Back when we founded the Solar Energy Society of Canada in the 70s, it was really really expensive.

Now it's cheaper than oil and competitive (if you removed the artificial cheap land leases and tax subsidies for coal) with coal.

So, getting a solar array up into space takes a lot of energy and resources per solar panel (even if film). Transmission also has a cost, and you have to build ground-based receivers - if they miss (drift) it becomes a nightmare.

The same total cost of materials and energy would be better used turning radioactive lands in Japan that nobody will live in, farm on, or work in, into solar panel grids placed over grazing land for experimental animal hybrids, quite frankly.

Not unless we have a space elevator

[wisebabo]

I'm afraid that even if Space X comes to the rescue and gives us a 2-order magnitude (factor of 100) reduction in launch costs it still doesn't make economic sense. As other posters have mentioned, why not just put it on earth? The relative lack of efficiency is more than made up for by not having to pay $$$ per kg to get it into geo-sync orbit. (However a great many cool, exciting and useful things like semi-affordable trips to space for the semi-rich and really good planetary exploration will become possible with a 2-order magnitude reduction in launch costs so let's hope that Space X can give us fully reusable launch systems!).

No, the only way this makes economic sense is if we have a space elevator (or cheap, lightweight nuclear fusion engines*, or anti-gravity, or giant swans pulling us in winged chariots to the heavens). Now there may be other applications (military? propulsion system for interstellar vehicles?) for having a large power station in geo-sync orbit but many of them don't make sense either (a simple bucket of sand at orbital velocities could do major damage to it).

*but if we have nuclear fusion, why would we need solar?

Re:Not unless we have a space elevator

[R3d M3rcury]

I'm afraid that even if Space X comes to the rescue and gives us a 2-order magnitude (factor of 100) reduction in launch costs it still doesn't make economic sense. As other posters have mentioned, why not just put it on earth?

It may make economic sense in Japan.

Here's some entertaining statistics: Japan has a population of about 127,000,000, or about 1/3 the United States. All those people live in 152,411 square miles, or a space about the size of Montana.

Imagine land prices in Montana if 1/3 of the population of the US moved there and you might start to get the picture. Remember, these are the people who built an island to put down an airport because there wasn't room.

Now extrapolate that population out to, say, 2030 (which is when they would be looking at having this working) and understand that they're probably not going to get any new land and you might start to see where it would make economic sense.

Re:Not unless we have a space elevator

[Ziggitz]

It would be super useful for establishing a power network for orbiting stations and possibly future moon bases. If we wanted to do any kind of fabrication in space or on the moon or to provide power for an ion engine we could just attach a microwave receiver to the vessel or station and viola, easy power without all the weight. For any very high energy intensive task you wouldn't need that level of power all the time, so it makes sense to make a dedicated installation for it and be able to beam it where it's needed.

Re:Not unless we have a space elevator

[Grishnakh]

It's worse than that. About 80% of Japan is mountainous. Almost all the population lives in the remaining 20% of that Montana-sized landmass.

Re:Not unless we have a space elevator

[Guspaz]

If you extrapolate the population of Japan out to 2030, you get... about 3.2% less people than today. They have a negative population growth rate.

On top of that, they have tons of usable space for solar: if nothing else, they have a huge amount of rail rights of way that they can put panels over, which gives them several hundred square kilometres of area usable for solar. I did the math in another post, and that alone could supply roughly ten times more power (in watt hours) as their one gigawatt orbital installation. It wouldn't be nearly enough to supply the whole country (maybe a tenth), but it's still far more practical.

Solar-pumped laser(s) instead of microwaves?

[kheldan]

How feasible/practical would this be? What would the efficiency be compared to converting sunlight to electricity, then to microwaves at high power (MW? GW? TW?) then having to 'receive' those and convert them to DC power?

its always sunny somewhere

[roubles]

If the goal is just to collect sunlight 24 hours a day, you could just build solar power stations across the globe. It would be a heckuva lot cheaper than building one in space. But maybe that makes too much sense.

Another thought that comes to mind is that the loss in power during wireless transfer would be significant. I'd love to see the calculations that show that this is more practical than collecting the energy on different locations on the surface of the earth.

Lastly, with all this talk of "supposed" global warming, I don't think we are going to do ourselves any favors by pointing concentrated microwave beams at earth ;-)

Re:But what does an actual physicist think?

[robmv]

“Anything one man can imagine, other men can make real.”
  Jules Verne, Around the World in Eighty Days

Re: If you're just beaming it down to earth anyway

[jxander]

Pretty soon (for various values of "soon") we're going to need power in space.

NASA is planning asteroid capture. Assuming it goes well and we don't kill ourselves, the next step is to mine the asteroid and use the raw materials to build a bigger Space Station or Lunar Base. Both of which will benefit tremendously from orbital solar platforms.

If we can get some power here on earth in the meantime, all the better.

Agreed: Start Here First

[xdor]

http://www.newscientist.com/ar...

Re:Agreed: Start Here First

[mark-t]

Not a terribly useful link if one does not subscribe to new scientist. Only the first paragraph is readable. The rest requires a subscription.

Re:Agreed: Start Here First

[xdor]

Yeah, I noticed that after I posted it... here's more about the foundation trying to do it:

http://en.wikipedia.org/wiki/D...

Imagine...

[Elledan]

Just imagine the massive nuclear power (fission and fusion) infrastructure (including reprocessing) one could construct for the cost of this project. No matter how one looks at it, this kind of space-based PV only gets attention because it seems so cool. In the end we can get a more reliable power infrastructure for less money simply by investing in what is a proven and known to be safe (though not idiot-proof, sadly) technology.

But hey, space. I'm sure it's far more cool and less controversial :)

Re:Imagine...

[Maury Markowitz]

> fission and fusion

Meh, fusion's just as bad.

http://matter2energy.wordpress.com/2012/10/26/why-fusion-will-never-happen/

Satellites have eclipses

[mangu]

In the geostationary orbits there are two periods each year, around March and September, when the satellites are eclipsed by the earth. That's why geostationary satellites need batteries, which are among the heaviest parts of a satellite. And, unfortunately for the power generation idea, these eclipses occur at night for a satellite located above the point it's beaming at.

As for the cost, launching 10,000 tons could be done for something like $50 billion or so. We are talking about a thousand launches, so it would pay to build your own rockets, which would bring the price down.

The exact costs of the launchers today is a closely guarded trade secret, but it's certainly less than the price you pay. Certainly, with a private company with development costs amortized over a thousand units, they could bring the launch costs to a less prohibitive level.

Re:Satellites have eclipses

[Teancum]

The cost of sending 10 metric tons to LEO and about 5 metric tons to GEO is claimed by SpaceX to be slightly under $60 million USD, or about $6k/kg. That seems to be at least a competitive price (few companies say they can beat SpaceX on launch costs). From this figure, sending 10000 metric tons to GEO would be something like $120 Billion. Some cost savings could definitely happen, although the reusable Falcon 9 with all parts being reused on multiple flights is still about $7 billion each, or dropping that price down to about $14 Billion.

Regardless, a guy who knows the figures for the solar power industry, Elon Musk, who also happens to own a spacecraft launching company as well as a completely separate solar panel manufacturing company (in the form of Solar City) has repeatedly said that spaced based solar power for terrestrial consumers makes absolutely no sense and is something he refuses to become involved with because he thinks it will be a financial disaster if anybody tries to get one going.

Re:Satellites have eclipses

[mangu]

The cost of sending 10 metric tons to LEO and about 5 metric tons to GEO is claimed by SpaceX to be slightly under $60 million USD

For a single launch. Ask them about their discount for a thousand.

Re:Satellites have eclipses

[HornWumpus]

Ask them to commit to a thousand launches in a set period and watch how much the price goes up.

Re:Satellites have eclipses

[Guspaz]

It doesn't matter. Even if you could argue that you'd get more energy from an orbital installation, it's still orders of magnitude more expensive than just building more panels on the ground and sticking batteries under them.

You can buy a 1kw solar panel for about $800. It'll weigh about 40 lbs. You can put that same solar panel in orbit, where it will produce twice as much power, for only $48,800. 2x the power for 60x the cost. And that completely ignores the cost of transmitting that power back to earth, and receiving it there, and the losses from that process, which would probably push the cost difference way over two orders of magnitude.

This is why orbital solar doesn't make sense, and probably never will.

Re:Satellites have eclipses

[Grishnakh]

The problem here is that Japan doesn't have any free ground to put that panel on, so you're mainly stuck with covering building rooftops with it. Also, Japan isn't a very sunny place, and has a high latitude. The losses in transmission should be fairly low by using microwaves at a frequency that don't experience much attenuation in the atmosphere (nowhere near as much attenuation as there is for sunlight). Maybe it still doesn't make economic sense even given these factors, but the equation is somewhat different for Japan than it is for other places.

Re:Satellites have eclipses

[Guspaz]

Japan has tons of free space that they could use for solar. If nothing else, they've got 27,268 kilometers of rail. With an assumption of a 40 foot wide right of way (a very conservative number), that's about 332 square kilometres that they can build solar panels over, giving them (at 5 full-sun-equivalent-hours per day) a theoretical power generation capacity of ~250 gigawatt hours per day. That would be a system capable of delivering an average of a bit more than ten gigawatts of power, a good deal more than their proposed one gigawatt orbital facility, and that's just from building solar panels over rail right-of-ways!

Re:Satellites have eclipses

[Grishnakh]

That's a good point. I wonder what the installation costs of that would be, versus the costs of building an orbital facility plus launch costs. (I imagine the ground-based option is far cheaper given current launch costs; eventually, with space elevator tech, the latter might be cheaper.)

Re:Satellites have eclipses

[Guspaz]

Space elevators might give us an order of magnitude reduction in launch costs (which fully reusable rockets also ought to). Practical orbital energy probably needs two or three orders of magnitude.

Re:Satellites have eclipses

[Grishnakh]

This is totally off-the-cuff, but it seems like space elevators should give at least 2 orders of magnitude reduction, certainly more than fully reusable rockets. The fuel cost is the big problem with rockets, and the whole problem with having to lift all the fuel, requiring even more fuel. Reusable rockets don't solve this problem, but space elevators do; the energy needed is quite small, and most of the cost is in the initial construction.

Re:Satellites have eclipses

[mangu]

Wut? Unless that set period is so short it needs building additional facilities, the price for repeated launches will only go down, never up.

Imagine the time period is the same you need for building a 1 GW power plant using any traditional technology. That will be a few years. Meaning you could do a launch every couple of days and complete a thousand launches in the same period. You could do that from a single launchpad.

The reason why they don't do launches day after day right now is because there is no demand for so many launches, but they certainly could adapt the procedures for that.

Re:Satellites have eclipses

[HiThere]

The problem with space elevators (and other sky-hooks) is that if the tonnage down doesn't, over time, match the tonnage up, the orbit decays.

OTOH, Why would a SPSS need to be built all at one go? And why only use it to power things on Earth? It would be great for powering ion rockets, etc., that are flying too far out to rely on solar power. And possibly one could design an electric rocket that was air-breathing at it's lower stages, so that after the first pieces of the SPSS were in place, it could power it's own construction.

That said, I'm still not sure it's viable. But it would certainly be interesting if it were.

Re:Satellites have eclipses

[Teancum]

You can get much better than two orders of magnitude savings off of conventional rocketry alone. Also note that fuel cost is one of the least important costs of rockets, even though the rocket equation requires you to carry that basically meaningless cost stuff up with you. What makes rocket fuel expensive, in orbit, is the cost of getting it there in the first place.

For example, with a Space Shuttle launch, the catering budget for the press corps covering the launch was more than the cost of the fuel used for the launch, at least for the liquid fuels being used. Far more was spent simply on the general labor that was used to essentially rebuild the Space Shuttle after each launch... especially the SSMEs.

I'll admit that perhaps some other alternative approaches to spaceflight including the classic Orion nuclear fission launch system might end up being cheaper and more efficient (definitely NERVA), but you need to consider infrastructure costs and regular maintenance as well when considering these other alternatives for getting into space.

Space Elevators in particular must be made with a mythical substances that as of right now simply does not exist. This Unobtainium must exhibit properties that no known substance has ever been demonstrated to hold at astronomical scales of construction that have never been attempted in the entire history of humanity. I also think that infrastructure costs for a space elevator are likely to be far more than proponents claim they will be, and more importantly a space elevator is completely incompatible with any other launch system. I think it is that last point which completely destroys at least a terrestrial-based space elevator.

A space elevator on the Moon is much easier to construct and can be done with high tensile strength materials that currently exist, and it wouldn't conflict with most other transportation systems including rail guns and most classical orbital inclinations that could avoid at least a few space elevators on the Moon. Some larger asteroids might especially be excellent candidates for space elevators, so I don't think the concept is completely devoid of consideration.

I am merely suggesting that an Earth-based space elevator is a hopeless dream until we have several hundred years of additional technological development in material sciences alone.

Re:Satellites have eclipses

[Guspaz]

Eventually, sure. But the first space elevator is unlikely to get 2 orders of magnitude cost reductions; estimates I've seen put it at something like $100 per pound, which is about 1/30th the cost of what a non-reusable rocket can do. Notably, that could change dramatically with reusable rockets, which is starting to look like a near-term possibility.

People forget that space elevators will be hideously expensive, and once you've spent all that money building the thing, you are both going to want to recoup your investment, substantially improve on it, and then make an ongoing profit. It can potentially reduce the cost of access to space, but only with incredible up-front costs, and there's no guarantee the long-term costs would beat out improvements in rockets.

Also, space elevators are currently impossible with modern material science, so there's that. And then there's the fact that space elevators can't get to low-earth orbit, that's kind of a limitation.

Re:Satellites have eclipses

[HornWumpus]

They haven't got any track record to speak of. If you ask them to commit to a schedule they will include the late penalties in the bid.

They are almost certainly ramping up at the best rate they can. If you want them to ramp faster for you, of course it will cost cubic dollars, diminishing returns and all. Add that to the schedule risk premium.

Your argument is basically: '9 women can have a baby in 1 month, maybe 7 or 8 if we get a few breaks.'

Re:Satellites have eclipses

[AmiMoJo]

Today it costs that much, but they are planning to build the first commercial scale station around 2030 when presumably costs will have dropped considerably.

Re:Satellites have eclipses

[Keith Henson]

Musk is right.

A reasonable economic analysis of power satellites requires about $100/kg for the cost of parts lifted to GEO.

You can't get that with rockets, not even reusable ones.

The main reason is that low exhaust velocity leads to rotten payload fractions. It's just physics, the rocket equation.

The proposed Skylon gets around 9 km/s equivalent exhaust velocity till it runs out of air, and 4.5 km/s from there up. Still too expensive by a factor of 4-5.

Leaving the oxygen out and using a 3 GW laser to heat hydrogen gives around 7.5 km/s for the last 6 km/s to orbit. The laser is hugely expensive, but run 24/7 it costs only a few tens of dollars a kg for 500,000 tons per year.

More here: http://theenergycollective.com...

Keith

Re:Satellites have eclipses

[catprog]

Do not use the normal solar panels, use the lightweight solar panels.

That reduces your weight to 10kg(22pounds) or only $26,840

Much better if you could somehow use materials already in space though.

Re:Satellites have eclipses

[Keith Henson]

"The problem with space elevators (and other sky-hooks) is that if the tonnage down doesn't, over time, match the tonnage up, the orbit decays."

That's not true. Long as the cable is tight, you can lift stuff forever without anything coming down. The cable does lean a little to the east, and it saps the earth's rotation to provide the velocity at GEO. Remember there is a rigid arm from the center of the earth to the base of the elevator. If the traffic tonnage is matched, the elevator will be straight, if more is coming down, it will lean to the east.

Re:Satellites have eclipses

[HiThere]

You may have a point. I've been mainly considering other skyhooks that are more reasonable to build.

Admittedly, the skyhooks that are easier to build don't drop the cost to orbit quite as much...but building them is a *lot* more plausible. We still don't have a cable strong enough to build a space elevator even without any cargo going up and down. A pin-wheel, however, could actually be built now. But, as with all unanchored sky-hooks, the time averaged mass up needs to equal the time averaged mass down.

The lunar option

[GPS Pilot]

If you cover a portion of the lunar surface with photovoltaics made from local materials, much less needs to be lifted up out of a gravity well.

http://news.discovery.com/spac...

Regardless of which concept ultimately gets pursued, it looks like the Japanese will be in the vanguard.

Re:The lunar option

[Guspaz]

The question is, how much mass would you need to lift to the moon to make mining raw materials and converting it into gigawatts worth of PV panels worth it? Consider also that it's much more expensive to land materials on the moon than it is to get it into geostationary orbit.

Where can i apply?

[zipherx]

I would like to apply for a part time job at the new facility in space.

Ciao

And it will be stopped later

[WindBourne]

The reason is that solar that is on the far side of the planet picking up energy 24x7 can only pick up light that would NEVER have gone to earth. As such, they are now going to beam all sorts of extra energy to the earth to use. It will be realized within 10-20 stations that it is another form of pollution, and a foolish one at that.

OTOH, these would make great sense to use for TEMPORARY situations, such as say the DOD's FOBs (which would normally be powered by diesel that costs from 100-400/gal), or for helping ships that are disabled, or for disaster areas.

And to be honest, the DARPA, the west, etc should be focused on beaming energy around with high efficiency, so that it could beam energy from the ground to space and back, OR can be used to drive various vehicles, such as earth movers.

Re: If you're just beaming it down to earth anyway

[Teancum]

Pretty soon (for various values of "soon") we're going to need power in space.

That is the reason why the ISS has a 300 kW power supply (essentially similar to the power production of a small municipal power plant for a couple of neighborhoods).

This is also one of the things that anybody talking about space-based solar power singularly refuses to acknowledge, and for reasons I really don't understand other than the insane costs that were involved with installing that much power into space in one place. If you want to understand the challenges and trade-offs of large scale power production in space, you must be a blathering idiot if you ignore the ISS as a data point in any of your calculations. The ISS power supply is a real example of a real device that is producing power for actual applications, having done so for a lengthy period of time.

The next step is to have other space-based assets that need large quantities of power, and regardless that implies trying to get the cost of launch into space much cheaper no matter how else you cut it. Extraterrestrial mining operations are something I expect to see by the beginning of the next century, but I'm not expecting much progress before then. We have a long way to go before something like asteroid-based Silicon is used for manufacturing photocells in deep space projects, where I also expect to see Martian colonization well before that happens.

Energy from space will increase global warming

[BBoom]

Taking energy from space that would have missed the earth, and beaming it down, will increase global warming. But how much? I've been hunting around for research on the effects on global warming of energy from space-based solar, nuclear power and the like, but haven't found much. I would appreciate it if anyone could point me at any information on this subject.

Space-based solar, and nuclear power, do have the advantage over fossil fuels that they don't generate greenhouse gasses. But they do introduce energy into our environment that wouldn't otherwise be there.

Truly renewable power systems (terrestrial solar, wind, hydro, tidal, biofuel) use energy already in our environment, so don't contribute to global warming.

It strikes me as ironic that the two major proposals for space-based projects related to global warming have opposite effects: spaced-based solar power will increase the amount of energy received from space, while the "solar sunshade" proposals would reduce it.

Re: If you're just beaming it down to earth anyway

[cpaalman]

If it had already been done, it wouldn't be newsworthy. Of course I'm not trying to discuss that. What I am commenting on is you're inability to read an article all the way through, and then comprehend the material enough to make constructive comments or critiques without ignoring some of the basic information that already exists in the article.

Re: If you're just beaming it down to earth anyway

[LordLimecat]

Its NOT explained above. Regardless of what portion of the spectrum PV cells are best at, the atmosphere filters out pieces of that spectrum. Ive seen no explanation for how the presence of 60+ miles of gases between space and the PV cell would enhance the quality of spectrum received by that PV cell-- other than that it would filter out really harmful solar events.

Re: If you're just beaming it down to earth anyway

[HornWumpus]

You must be new here.

Reference Slashdot on Slashdot

[xdor]

Actually this would have been best: http://hardware.slashdot.org/s...

off the top of my head

[gzuckier]

Solve the problem of the incredible energy cost of getting into orbit (compared to the minimal cost of running around the solar system once you've achieved orbit). It's been suggested to use a ground based laser focused on a tank of water or something similar in the ship as reaction mass, kind of a steam powered orbital booster, for the savings in not having to haul the whole rocket fuel up. How about using the space solar collector to power the laser, focused down onto the rocket? No more dangerous to the rocket as a ground based laser, no more dangerous to the earth end as the launch site for a chemical rocket. I'm guessing there might be decent efficiency compared to using earth based power stations of any variety to power the laser. Might not be the ultimate best way to get to orbit, but seems to me like a slight enhancement of the aforementioned ground-laser powered launcher.