This Satellite Could Be Beaming Solar Power Down From Space By 2025 245
Daniel_Stuckey writes "A NASA veteran, aerospace entrepreneur, and space-based solar power (SBSP) expert, [John] Mankins designed the world's first practical orbital solar plant. It's called the Solar Power Satellite via Arbitrarily Large PHased Array, or SPS-ALPHA for short. If all goes to plan, it could be launched as early as 2025, which is sooner than it sounds when it comes to space-based solar power timelines. Scientists have been aware of the edge the "space-down" approach holds over terrestrial panels for decades. An orbiting plant would be unaffected by weather, atmospheric filtering of light, and the sun's inconvenient habit of setting every evening. SBSP also has the potential to dramatically increase the availability of renewable energy."
My god, what has science wrought??? (Score:5, Funny)
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It basically works like Ion Canon and it will accelerate global warming and destroy the receiver station.
Re:My god, what has science wrought??? (Score:4, Informative)
Ion Canon
I think you mean "ion cannon" unless you're talking about the definitive collection of published works on ions.
An ion cannon works by projecting a beam of charged particles, either atoms or molecules, not a beam of microwave energy.
And, no, it's not going to destroy the ground station.
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Ion Canon
I think you mean "ion cannon" unless you're talking about the definitive collection of published works on ions.
Perhaps the GP meant Canon Ion [camera-wiki.org].
Re:My god, what has science wrought??? (Score:4, Funny)
I'm curious - how much taxpayer funding has this received? Is this just another one of the "ride the replace-fossil-fuel-usage bandwagon" schemes?
Re:My god, what has science wrought??? (Score:5, Insightful)
I'm curious - how much taxpayer funding has this received?
Less than a day's worth of military funding, I'm sure. And this is not an expenditure, it's an investment.
Re:My god, what has science wrought??? (Score:5, Interesting)
"Less than a day's worth"
You''re being WAY to generous, the US military spending for 2012, ignoring all of side costs (possibly as high as $500 Billion) is roughly $900 Billion dollars. Broken down to a "By Day" cost it is $2.46 Billion per day, with that kind of money you could probably finish development and put a significant amount of this concepts hardware into orbit. If any taxpayer money was used on this study it would probably be measured in seconds of military spending (~$28,500 per second) at most.
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And this is not an expenditure, it's an investment.
Nope. If tax dollars are being spent, it is an expenditure. If it was an investment, it would be funded by private investors risking their own money.
Re:My god, what has science wrought??? (Score:4, Informative)
IMHO, the single biggest problem in the US is that there are way too many people like you who reduce ALL government activity to a single simple minded complaint; "Waaaa.....they're spending my money...Waaaaa!"
Re:My god, what has science wrought??? (Score:5, Insightful)
I can't help but notice that you're comparing with social programs, and the DoD, which is grossly overfunded, is thrown in as an after thought. Goes to show why the US is in such trouble. Wellfare programs are essential, but get relatively little money. But, the DoD, gets a crap load of money, with little or no benefit for the funds.
What's more, a huge number of the people on welfare are there because we signed all those free trade agreements and shipped the decent paying jobs overseas. All while making it harder and harder for employees to organize, and slashing taxes that the rich pay.
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You conflate welfare with social programs. Social security, legally defined as a welfare program, also counts, and is far and away the biggest share of this.
Good luck convincing any politician to reduce social security payments to everyone by a dollar a month to fund this.
Re: My god, what has science wrought??? (Score:3)
How the hell is social security "welfare" when I pay the max into it every year?
You want to make the case for modifying it then go ahead, but these constant attempts to redefine it are garbage.
Is the mortgage interest deduction included in your 2.3 trillion? IMO that's much more of a welfare program than social security, so lets cut that first ok?
I say that knowing I'll lose close to 10k per year (net).
Re:My god, what has science wrought??? (Score:5, Informative)
The $600 Billion that you quote does not include all military spending. quite a bit of the $2.3T you list for social spending includes military pensions, the GI Bill, and the VA hospitals:
That is about $1.1 trillion more than we took in in taxes. The way our 'National Defense' spending is skewed towards big contractors and away from the soldiers, I would probably guess that there are quite a few veterans in the 'Government Welfare' figure as well.
The 'All Other Spending' includes foreign 'Military Aid'. The majority of which goes to Israel, Afghanistan, Pakistan, Iraq and Egypt to help pay for their military budgets. Total Foreign Aid comes to about less than 1% of budget. About $14 billion in foreign military aid, $23 billion in foreign humanitarian and developmental aid and $18 billion in 'other' foreign aid.
So there is military spending that is outside the pentagon's budget. A lot of it, for soldiers and veterans, gets included in the social spending.
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Yeah we could have 50 of theses for the price of the iraq war.
It is a logical fallacy to attempt to justify an expenditure by pointing to something else even stupider. This project should be funded if, and only if, it is a good idea, not because it is merely less stupid than something else.
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You clearly don't understand how funding grunts work...
Re:My god, what has science wrought??? (Score:4, Funny)
Moon, Death Star, whichever.
lol (Score:5, Interesting)
not even mentioning the fact that if you had 40km^2 of land you could just set solar panels there and do the thing for yourself with much less energy losses.
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Which makes me wonder, could this be used as a weapon as well? Why not design it so the beam can be focused and used as a death ray? This will enable DOD funding which should bring it into production ASAP. A dual purpose device for power generation or weapon of mass destruction.
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Now that's "Real Genius" there.
http://www.imdb.com/title/tt0089886/ [imdb.com]
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The weapon in the movie was fired from the bomb compartment of a B1 Bomber, so would have been much closer to the target than a satellite weapon. It was a pretty tight beam (although apparently sufficiently diffused by aluminum foil to make its military usefulness a bit suspicious...), and could easily burn through everything except jiffy-pop pans, making all highly fortified bunkers not shielded with a layer of jiffy-pop vulnerable.
I'm not sure what the characters in the movie were upset about. The purpo
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The problem there is that hitting a football field sized antenna is harder than hitting one that cover 30 square kilometers. You'd have to have a more advanced targeting system and you'd still have to put the most expensive part in space.
Also, nice mixing of units, can I get this in LoC or hogsheads?
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The technology is already good enough that you don't need that large an antenna. The antenna is designed to allow the capture of a lot of power at a low intensity. IIRC microwave power transmission is over 90% efficient at low intensities, though in this case you also need to use a wavelength that the atmosphere is transparent to. That means that it treats water vapor as transparent. Probably also liquid water (rain, sleet, snow, hail, you), because if they absorb energy, then it can't be picked up by t
Japan and the ESA are doing it too (Score:5, Interesting)
Japan is already working on a prototype solar power satellite. The ESA has an active project. I'd hope NASA could work with them on this one.
Nope. (Score:5, Interesting)
The energy needed to put solar cells into orbit is not recouped over their lifetime outside the protecting atmosphere. Solar cells are used on spacecraft out of necessity, not because they're cost efficient.
I know this is an unpopular view on Slashdot, where atomic energy fans come together to bash all other technologies, but solar cells work fine on the ground. You can fill the supply gaps with conventional power plants and still come out far ahead CO2-wise compared to the current power mix. Production has hardly scaled up, but solar cells are already competitive in some markets. The point of these stories about satellite solar farms is to give you the impression that there needs to be some extraordinary investment or innovation before solar power can be used. That's a lie, designed to put a drag on solar power. Solar power is ready to be used, you just have to do it.
Re:Nope. (Score:5, Insightful)
Agree with the poster. I figure solar cells in space will not trump solar cells on the ground until we dramatically lower the cost of delivery to orbit. At the moment we SpaceX is quoting 4300 USD/Kg to orbit on a Falcon 9 (1.1 - still waiting on maiden flight Sept5), and maybe down to 1200 UDS/Kg for the not yet built or demonstrated Falcon Heavy. And that is to LEO, Solar Cells probably need GTO which is about twice as expensive. I can't imagine a space based array can be competitive at those prices.
Now if someone built a rail-gun based launcher, then maybe it could make sense.
And as AC mentioned, we are in the midst of a ground based solar cell revolution right now. Very cool...
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I agree that putting a solar collector in orbit would be extraordinarily expensive using any currently extant technology. As would be maintaining it. On top of which, what would the point be? Solar energy can be collected on the surface at a small fraction of the cost and a technician can drive or walk to any component needing repair, Sure, a ground based facility might have to be larger than a space based facility, because of atrmospheric and sun angle losses. But not enough to make much difference?
BT
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An ion thruster I suppose would do the trick. Of course it would run out of Xenon after awhile, but ion engines have the highest fuel to force ratios short of a solar sail.
Actually come to think of it I am not sure it is much of a problem. If you were in a geosynchronous orbit, surely the solar pressure would push you away half the time, but push you back the other half, right?
Re:Nope. (Score:5, Insightful)
I think, and I'm not as smart as I once was, so this an opinion, not a statement of fact, that a geosynchronous satellite would be eclipsed by the Earth for a significant percentage of the time. There's probably an orbit that maximizes energy collection, but I don't have the slightest idea what it looks like.
Not all that significant. Remember that the Earth's equator is inclined about 23 degrees relative to the plane of the ecliptic. Because of this tilt, combined with the distance the satelleite is from the Earth, a solar power satellite will experience *no* eclipses from the Earth for about two thirds of the year, and some period of eclipse during the remaining third. But even at the worst point in the cycle, the eclipse period is only about 70 minutes per day.
Net result is that a good old geosynchronous orbit is good enough for a solar power satellite (and greatly reduces the headaches of keeping the power beam targeted at the receiver).
Re:Nope. (Score:4, Insightful)
Although it may not be economical, there are significant advantages in space vs ground. Average daily insolation is at least 4X better. Because putting the space panels in place is so expensive, the fractional increase in cost of using high-tech panels is smaller: a 60% power/area (power/mass) improvement over single-crystal silicon.
As long as the solar pressure on the installation is less than the Earth's gravitational pull, it should be possible to design an orbit that will keep it in place. After all, when the installation is nearer to the sun than the Earth, the sun's radiation is pushinf it toward the Earth.
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> Average daily insolation is at least 4X better
And transmission losses take 1/2 of that.
Cell lifetime takes another 1/2.
> the fractional increase in cost of using high-tech panels is smaller
That is the most bizarre argument I've heard in a while.
"No one can possibly afford this car, so we may as well make it out of solid gold."
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If we had a space gun or a space elevator or space manufacturing then it would make sense. But you know what might make more sense? Nuclear plants in space, beaming down their power. Then you don't have to deal with all that surface area.
On the other hand, a space-based array could use roll-out thin film panels, because they don't have to resist gravity...
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The JAXA and ESA plans both assume that only small scale systems will be used at first, probably for disaster relief and maybe military use (powering military devices, not as a weapon itself). When the cost of orbiting stuff comes down it will then move on to large scale commercial operation.
Skimming TFA it appears that this is how NASA sees it as well.
Re:Nope. (Score:5, Informative)
Here's some hard numbers on "traditional" approaches to solar ground vs space:
http://physics.ucsd.edu/do-the-math/2012/03/space-based-solar-power/ [ucsd.edu]
"You can even throw in batteries in the ground system without exceeding the space cost, and all the reasons for going to space have melted away."
It would be interesting if TFA had some hard numbers to compare against in terms of generation capacity vs launch costs vs upkeep/replacement schedule... Can't find anything myself though...
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Although the costs are hard to tie down, your citation seems to imply a disadvantage of space solar over ground of at least 4X, and some of the assumptions are open to challenge. Substantial improvements in a variety of technologies would be needed for space to be as practical as ground.
Still, I like the idea of at least doing some trial to work out bugs and make a standard for future experiments to be compared against.
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"Substantial improvements in a variety of technologies would be needed for space to be as practical as ground."
This is the lottery fallacy.
For argument's sake, let's say there are 1000 technologies in an SPS system - rocket engines, solar cells, lightweight aerostructures, turbo pumps, new inverter topologies, etc.
The vast majority of the list of possible improvements improves both the ground and space-based systems. For instance, if you improve the performance of solar cells, then both the ground and space
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"microwave link to the ground. "
And there' the problem with his argument. Taking existing tech and retro fitting to the application. I rather have batteries constructed in space (via mining asteroids) and 'drop shipping' them to the ground. Then being recycled when used up. Hopefully by the time we have too much to recycle, space elevators will be created of the cost of shipping stuff back into space is 1/20th the current costs.
The current thoughts about space based power does not take an integrated approac
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You can fill the supply gaps with conventional power plants and still come out far ahead CO2-wise compared to the current power mix.
Not to mention that the periods where most power is being used is during the day, where solar power produce power, so solar power fits well with our current power consumption.
Production has hardly scaled up, but solar cells are already competitive in some markets. The point of these stories about satellite solar farms is to give you the impression that there needs to be some extraordinary investment or innovation before solar power can be used. That's a lie, designed to put a drag on solar power. Solar power is ready to be used, you just have to do it.
There is one issue with solar power (and a number of other renewable energy sources): They are not stable. Power output is dependent on weather patterns. Solar power has the additional issue that there is no output at night. The satellite solar farms is one way of getting around it. Another is to improve technology to store power, or t
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The energy needed to put solar cells into orbit is not recouped over their lifetime outside the protecting atmosphere.
It doesn't take that much energy. I think it's more to make them in the first place. Well, maybe I'll run some numbers to see what the relative costs are.
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Look, we can''t even manufacture duct tape in orbit yet. Much less pure silicon.
I hope you're a very patient fellow.
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"I know this is an unpopular view on Slashdot, where atomic energy fans come together to bash all other technologies"
It's the same everywhere. And I really don't understand why. All logic suggests nuclear supporters should be equally supportive of solar as well. Bunker mentality?
http://matter2energy.wordpress.com/2013/02/19/why-solar-is-nuclears-best-friend/
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Those aren't facts, those are a subset of the facts edited to support your point of view. You're leaving out things like the 19k gun suicides compared with the other 12k gun related homicides in a typical year in the US. And the fact that in Australia when they changed their gun laws to take the excess guns off the streets, they've had only 1 mass murder in 10 years, and that one used a knife, IIRC. And that one incident was a smaller number of people killed or injured than the typical US shooting spree. Co
This is way off topic (Score:3)
This is way off topic, but I'll bite anyway.
The text of the second amendment is thus:
A well regulated militia being necessary to the security of a free state, the right of the people to keep and bear arms shall not be infringed.
The first clause is an explanation for the second, and the amendment clearly places a limit on the power of the federal government (later amendments and rulings mean that this also affects the states). And that limit is that congress does not have the power to infringe the right of the people to own and carry weapons.
It does not say what kind of weapons. It does not grant congress a "reasonableness" pass, to allow them
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Zero.
I don't think that concept means what you think it means.
Single Point of Failure 'Fail' (Score:2)
Energy is life and civilization. Balancing an industrial society on the razor edge of a single point of failure is itself a 'fail'. Whether the failure would occur technically or politically is of little consequence.
The catch-22 is impossible to avoid. If orbital solar doesn't scale then it is a waste of resource, if it does then it's a single point of (catastrophic) failure.
Terrestrial power plants can be replicated easily, hardened from sabotage, operated and maintained within many sovereign countries at
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However, storing excess energy using hydrogen or molten salt might be good enough to keep things ticking over until repairs are done. But of course this is just a band-aid solution.
But obviously solar plants would be great for refining ore mined in space before it is plunged down to earth where energy is more expensive (or it could be manufactured further in space, eventually).
As long as we keep it... (Score:2)
LOL (Score:2)
In no way is this a "Lets put up a microwave beam weapon satellite and pretend that we are beaming power down by installing a secret Nuke reactor under a big dish."
what could go wrong? (Score:2)
What could go wrong when pointing a large microwave beam at Earth?
It's a cover (Score:3)
Space-based solar doesn't make a lot of sense until we get a whole lot closed to a Kardashev Type I civilization than we actuallly are. There's simply no way that firing panels into space on a $100 million dollar rocket is more cost effective than sticking them on the ground where Bob the Electrician can install and maintenance them.
It does make sense though in some *very* limit circumstances. If you frequently work in areas that have no power infrastructure, and can afford the jaw-dropping premium of space-based power. Those two facts suggest this is the public face of some kind of military or intelligence project.
Re:It's a cover (Score:5, Funny)
Yeah, we're more of a Kardashian Type ''civilization' now.
We're doomed.
How efficient is this thing? (Score:2)
"no night" orbit? (Score:4, Interesting)
The only orbits that have no period when the sun is blocked by Earth's shadow ("night") are polar (remember the pictures of sunrise over the Earth shot from space by various astro/cosmonauts?). No single ground station could receive the power.
Also, there would be considerable photon pressure pushing the satellite(s) away from the Sun and, hence, Earth, plus gravitational drag attempting to pull the orbits around he Earth. Not a big deal for a short-term recon satellite, but these would be intended to there for years. Any of the rocket scientists out there know if the polar orbits are even vaguely stable, or will the satellite need boatloads of fuel to stay where it's needed. Of course, the beam of Earthbound power is a thruster, too, raising the orbit.
Put the collector at the Eath-Sol L1 and you've got to have REALLY good beam control to keep from raising the temperature of the entire Earth.
Sounds more like weapon than a power source to me.
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What you say would be true for a low alititude orbit.
According to Tom Murphy's analysis: http://physics.ucsd.edu/do-the-math/2012/03/space-based-solar-power/ [ucsd.edu] a satellite in geosynchronous orbit is so far enough away that it is only shaded for a very short period of time per day, and then only when it is near the equinox so that the earth is directly between the sun and the satellite, resulting in about 0.7% shaded time on average.
Or course at the end of the day the economics still don't seem to work out for
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True Quantum Devices (Score:2)
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"the receiver on Earth will be large—about 6 to 8 km in diameter, positioned 5 to 10 meters above the ground. It will be constructed from millions of rectifier diodes—true quantum devices—wired together." I had no idea they've been building quantum devices since the 1950's.
You know, we've had quantum mechanics since the 1920s or so. I'm not sure how much the first solid state diodes were based on quantum theory or simply empirical knownedge, but by the time the transistor was invented in 1948, they probably had a pretty solid (pun intended) idea about the role of quantum mechanics.
What about flairs? (Score:2)
Bad idea (Score:3)
Last time I did something similar in Simcity, my city got attacked by aliens...
Re:Control API Security (Score:5, Funny)
would someone please at least a security engineer before they design the control API for the thing?
No. There's no pleasing security engineers.
Homer Simpson will be the safety / control room gu (Score:2)
Homer Simpson will be the safety / control room guy
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the microwave downlink gets misaligned and burns down the city block next to the ground station.
TFA seems to imply that they considered the issue of using lasers and shot it down with the words:
High frequency blasts can damage retinas, destroy electronics, and potentially ignite fires or explosions. “Think about the Death Star,” he warned. The risk factor outweighs the seductive, compact grace offered by lasers.
As you note, however, microwaves are not entirely safe either. On the other hand, if the intensity is low enough it should be safe, which is what is being discussed:
Since Mankins is dead-set on low-intensity microwave transmitters, the receiver on Earth will be large—about 6 to 8 km in diameter, positioned 5 to 10 meters above the ground.
The obvious question is if the beams can be focused, and used as a weapon, it could provide a no-warning and very destructive attack anywhere in the world. It seems to be what Mankins is trying to avoid, and I tend to agree that (aside from cost) we
Re:It's all good until (Score:4, Insightful)
It seems like the fear of weaponisation is whats kept this sort of thing from being explored more fully, up till now of course, but I think that there are logical arguments that prevent this from being an issue. For instance if country 1 put up enough of these things they would be able to supply a large proportion if not all of their countries energy needs creating a significant economic advantage for country 1. Said country then decides to point one elsewhere to burn down a city or military installation in country 2 therefore breaking the International space treaty and probably many others, and the international community forces country 1 to dissasemble their SPS-alpha capability, causing them severe economic dissadvatage.
TLDR using these as weapons makes no economic sense.
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I'm not quite sure I entirely follow your logic or agree with your assumptions/conclusion.
You're surmising it doesn't make economic sense to use these as weapons simply because you've assumed the international community will be able to dictate that the offender dismantle the entire fleet of satellites?
Let's back up a bit. Not that it's entirely clear in your portrayal, but if country 1 is the only country with these things... and a lot of these things... I don't think it would be an "oops" moment after the
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Most likely this would be restricted to countries like the US that have a huge amount of space that's largely uninhabited. Unfortunately, I'm not aware of any such nation that's also located close enough to the equator to have a geosynchronous orbit. IIRC, you really need to be within about 10 degrees of the equator, or something like that. If you get too far away, then the speed necessary to keep the satellite in orbit prevents it from staying directly above the receiver.
The other alternative would be figu
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Better than nukes. Nukes kill people - a microwave death star could fry anything with a long enough cable and leave people unharmed. Power lines, telephone cables. Zap a city before invading, or use it to disrupt enemy communications during air strikes to buy a few minutes longer before they can respond.
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"It seems like the fear of weaponisation is whats kept this sort of thing from being explored more fully"
Oh gebus, no. What's keeping these things from being explored is that anyone with a pocket calculator can easily determine that it can not possibly work.
http://matter2energy.wordpress.com/2012/03/17/the-maury-equation-redux/
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And even if it did work, it'd cost a ridiculous amount of money. So much money that the only way I can imagine any country building it would be as a covert weapons program.
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The problem is: How do you prove that it was an intentional event, as opposed to a malfunctioning of the controls?
The same way it's done when a malfunction causes a nuke to be fired at another nation?
Or what if one country hacks into another country's control system and uses one of their satellites as weapon? If the satellite happens to be on the other hemisphere (so there's no danger of accidentally hitting the own country), they don't even need to have control. Just DoS the other country's control, and have the out-of-control satellite burn populated areas at random.
It's a risk, and so is pretty much everything. Nuclear plans, research facilities handling hazardous biological materials. One would hope these satellites would have a few fail safe mechanisms built in to them:
1) Suspend the beam if contact with control is lost. They'd be pretty amateurish if they designed this so a DoS could allow people to use it as a weapon.
2) Isolated systems to confirm the location of the beam's targe
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That's sort of how it's done with nuclear power, the control rods default to being all in the core and the fuel rods default to being out of the core. So, barring the case where something comes in and prevents that from happening, the reaction comes to a gradual slow down and stops.
Presumably, a satellite like this would be designed to default to off and require intervention to keep it on.
Re:It's all good until (Score:4, Insightful)
Modern nuclear plants have failsafe after failsafe. The control rods are held out of the core electromagnetically, so if the control system loses power they'll all drop instantly an initiate SCRAM.
The reactor can still be dangerous afterwards, though - the unstable isotopes produced as a byprodct of fission continue to delay. That's what happened at Fukushima - the SCRAM worked perfectly, rods dropped the moment the earthquake hit, but the earthquake and tsunami managed to destroy not only the cooling system backup generators, but also the switchgear that connecte up the backup backup generators and the backup backup backup 'We're really screwed now' emergency external power interface for connecting portable generators or feeding power back from the grid. There was a design flaw in there - although there were four seperate means of powering the cooling system and full redundency in the switching, both that switching and the redundant backup were located in the main turbine hall, a room that the tsunami flooded.
Despite all that panic though, Fukushima has a total of *zero* deaths as a result of any nuclear accident, and contamination of the surrounding land is minimal. The ocean took a lot of radiation, but all short-lived isotopes.
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The problem is: How do you prove that it was an intentional event, as opposed to a malfunctioning of the controls?
Or what if one country hacks into another country's control system and uses one of their satellites as weapon? If the satellite happens to be on the other hemisphere (so there's no danger of accidentally hitting the own country), they don't even need to have control. Just DoS the other country's control, and have the out-of-control satellite burn populated areas at random.
Something like a system whereby the satellite will only transmit when it is within a fraction of a degree of its normal orientation, or a signal constantly transmitted by the base station when it is receiving, a combination of both. That's just off the top of my head while I'm at a party I'm sure the researchers involved have thought about this a lot.
Re:It's all good until (Cost Benefit Analysis) (Score:3)
The obvious question is if the beams can be focused, and used as a weapon, it could provide a no-warning and very destructive attack anywhere in the world. It seems to be what Mankins is trying to avoid, and I tend to agree that (aside from cost) we really, really need to make sure that the power sources of the future are not just being used to cloak the real objective: Making powerful weapons.
Let me help you with that. The answer to your obvious question is "yes". Hence the problem...
Of course there are
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"The cost per watt of the panels is order of $1 (probably less, at this scale). "
We sell 1st tier, 3rd party warranty panels for 69 cents RETAIL. Large-buy wholesale prices are around 50 cents right now.
"get ten times the power per square meter"
Raw numbers are about 8 times. But then you have to consider the lifetime of the panels (1/2) and the transmission losses (1/2) and you'll end up with the space panel making perhaps 2 times as much power at any given time, and 1/2 over it's lifetime.
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No argument from me. I was presenting the most favorable case (made a few years ago -- PV solar keeps dropping (and, I think, will continue to drop) and as I noted, cheaper solar cells favor ground based installations even more because you have to pay truly absurd amounts to lift any solar cell into orbit, many, many times the actual cost of the cell.
I was equally generous in guesstimates of transmission efficiency (trying to make the case FOR as best I could) but yeah, even though "in principle" microwave
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"I was equally generous in guesstimates of transmission efficiency (trying to make the case FOR as best I could) but yeah, even though "in principle" microwave power transmission can be as high as 90% efficient, I'd be rather surprised if it averages 50%."
Yeah, this one is murder. The transmitter is about 70% efficient, the receiver about 90, and modern inverters are about 95%. So .70 x .90 x .95 = 59%
To all the kids reading this. LEARN F'ING MATH. It will save you from believing in all sorts of BS like thi
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It is indeed finding and excuse to build rockets and space stations, which rarely make sense at $10,000/kg except for one-off research platforms and for communications.
In NC electricity is a lot cheaper -- that's why I just can't make it work. OTOH we probably get a lot more sun than Toronto:-). But as you say, it keeps dropping. I was shopping in West Marine for boat stuff and took a moment to look at their 90 and 130 W polycrystalline panels -- for almost exactly $1/watt, with (boat scale) inverters in
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You wouldn't even have to focus it. Even at a low power level, it could very effectively impede the operation of radio communications.
There's only so much that a country like the US could do with that - they are as dependant on battlefield communications as anyone. But think of how it could be abused by, say, China. If there's an embarassing scandal somewhere (preventable disease outbreak, building collapse due to lax government maintainance, etc), they can 'misalign' a beam to knock out all radio-based com
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"the microwave downlink gets misaligned and burns down the city block next to the ground station."
Which they "solve" by placing the ground stations in the middle of nowhere. Which of course raises all the transmission-to-the-customer problems that this system was supposed to solve.
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In the designs I've previously seen, you don't need to "solve" that problem, because it just doesn't exist. The prior plans called for the area under the microwave antenna to be pasture land. They didn't want it to be residential because there was no evidence that low level exposure to microwaves over a long period of time was safe. Short periods of time? No problem. You have much less intensity per square cm than you have in a microwave over. That's why the receiving antennas need to be so large. (B
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-MICROWAVE POWER- in simcity 2000 (Score:2)
it should be hear in 2020 but in 2050 FUSION power is better.
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If SimCity has taught me anything, it's that it's cost-effective and, indeed, safest to bulldoze and rebuild power-plants every 49 years, exactly.
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Just place the ground station somewhere nobody will give a shit about, like Jersey.
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Go find a discarded old style rear projection TV. disassemble to get the giant Fresnel lens out of it.
You now have your very own death ray that will set wet grass on fire and scorch concrete.
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Liar. I tried that last night and it didn't work at all.
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You had it facing the wrong way.
Re:So why not...? (Score:5, Informative)
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The design being discussed has an intensity at the ground of 1/4 sun.
That's like standing a few meters away from a microwave oven with a broken safety interlock running with the door open. No thanks.
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Lets think about that.
The solar constant [wikipedia.org] is about 1.36 kW/m^2. One quarter sun would be about 0.34 kW/m^2.
My microwave magnetron output is 0.75 kW. Spread out on a sphere of 2.2 m^2, this is 0.34 kW/m^2.
The area of a sphere is 4*PI*r^2, so r = 0.42 m
I was wrong. Its like standing in front of a microwave with its door open a little less than half a meter away. I was being conservative in my previous post.
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I remember a proposal like this back in the 1960's. My first question then is my first question now: If a satellite can "beam down" enough power to be useful as a power source, how is it not an orbital directed energy weapon?
Forgot to read TFA again, did we?