8 ms·
China wants to put a solar farm in space by 2025
- kdmedev 8y agoFinally, somebody decided to make solar collectors in space. Been waiting for it since it was discussed in Isaac Arthur. I bet spaceX might do something similar in the future. When they are not as encumbered with star link and the BFR.
- AstralStorm 8y ago1) It is not much more efficient due to transmission losses. (Compared to high voltage DC.) 2) The costs, on top of super expensive solar panels, make this totally pointless economically. Solar panels are hard enough to maintain on Earth. 3) It's a multi gigawatt level microwave gun in space. Want to blast some lightning onto someone? Sure, now you can. Or fry it.
- ReptileMan 8y agoWell... I mean china is pretty capable of breaking the kneecaps right now of whomever they want in their territory. I doubt they will use it as ion cannon.
- Shivetya 8y agoThe costs just to put the materials up there makes me wonder the long term viability of just trying to source it from the moon. By the time you are willing to spend the billions required it cannot be much more of step and provides other uses. still I have to agree, how do you even maintain something like this. it would probably lead to a full time presence in space unless robotics become just that good. I just don't see the ROI except may be for national pride.
- adrianN 8y agoI'd guess you maintain it by replacing the satellites. We're pretty good at maintaining satellites by replacement.
- JoeAltmaier 8y agoEconomics changes all the time. The launch costs are supposed to come down. The cost of getting land for the cells and transmission lines goes up all the time, which makes orbit actually more attractive. The weight/cost/efficiency of panels gets better all the time. And the efficiency! 10X the solar flux outside the atmosphere! And in the right orbit, 2X again because of course night quits being an issue. So a potential 20X better utility per square.
- entity345 8y ago> Solar panels are hard enough to maintain on Earth. Isn't the main issue that they get dirty, though?
- mooreds 8y agoI think they just degrade the same way they do on Earth. This PDF from 2003 talks about a 0.5% yearly degradation, which, if I recall correctly, is similar to ground based pv. https://www.google.com/url?q=https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20030068268.pdf&sa=U&ved=2ahUKEwj9nISuycXgAhUH44MKHYYAAk4QFjABegQIBxAB&usg=AOvVaw00teHST4Dc7O6YkeLc8Koj https://www.google.com/url?q=https://ntrs.nasa.gov/archive/n...
- gotocake 8y ago3.5) The giant MASER in space is also a sitting duck target, so it’s shit as a weapon, and disrupting a nation’s power supply is as easy as “shooting” back.
- 44Aman 8y agoHow do they plan to beam energy back to Earth?
- rohan1024 8y agoLasers? Microwaves? I'm just speculating but I don't see another way.
- NikolaeVarius 8y agoPresumably lasers. A small part of me wants to see this turn into China deploying a solar powered death laser under the guise of a green energy initiative.
- ovi256 8y agoThey'll recharge batteries that they'll then return to earth on a cheap BFR-like reusable launcher. /joke Internet points to anyone who computes: - how expensive that makes the marginal kWh returned to earth likes this. - how low launch and return-to-earth costs must go for this to become competitive with current kWh costs.
- adrianN 8y agoFirst you build a space elevator to geosynchronous orbit, then you can use full batteries as counterweight for lifting empty batteries. That way you only have to overcome friction losses.
- ovi256 8y agoEven better! Now it's less of a joke idea. You still have a small shuttle transfer from geosync orbit to wherever the solar farm is (heliosync or a lagrange point to avoid earth shadow), but the delta-v for that is tiny. However space elevators are still soft SF (still missing a material with enough tensile strength), whereas BFR cheap reusable launchers are hard SF, achievable with current known tech.
- cf141q5325 8y agoIts in the article >China's proposal, meanwhile, appears to suggest converting solar energy into electric energy in space, before beaming back to Earth using a microwave or laser and feeding into the grid via a ground receiving system.
- neals 8y agoThey intend to beam the energy to earth through a laser. I wonder if building a space-mirror and focussing a beam of sunlight would be a much easier and scalable solution. Though I guess you would need multiple base stations to beam it somewhere where there's no clouds?
- En_gr_Student 8y agoUsing a wavelength transformation to send this through the non-absorption windows means more energy hits the ground and you aren't hacking terrestrial albedo in a bad way. That global warming is about absorption of sunlight, so putting a lot more sunlight on the same absorption percent means more heat retained. It doesn't do any good to cut gwp materials in the air, then increase sunlight hitting the atmosphere in a way that makes heat retention higher.
- AstralStorm 8y agoActually, maser - microwave laser. The mirror is a fine grid which makes it much lighter and more resilient, and it is much easier to convert into electricity than light.
- En_gr_Student 8y agoI was pushing this a decade ago. If you have "fusion in a bottle" and don't want to share, this is a decent way to make it harder to steal/damage/use-for-terrorism. Also, giant beam transmission facilities and giant beam weapons aren't so different from each other. There are going to be detectable critical differences, but with some modifications one can be made into the other. Radiation damage is going to be a challenge but satellites do with solar for a long time. Onboard robots?
- 0xcde4c3db 8y agoI wonder whether this meant to imply military capability, in the same way that the space race was basically a way to advertise ICBM capabilities.
- dalbasal 8y agoIn the sense that fancy hats imply virility.
- dexen 8y agoA doomsday weapon in space. As the article mentions, the station will beam the collected energy down to Earth. Whether in visible light, microwave or any other spectral band, it will need two things for everyday operations: - ability to point the beam at an arbitrary point on Earth, to track the collector ground installation, and - ability to focus the beam to proper size The second capability is crucial; if it's fixed focus - and one with sufficiently large footprint at that - and fixed orbit, it would be safe. However having either adjustable focus, or adjustable orbit[1] makes this a proper weapon, due to the possibility of pointing multi-megawatt beam of energy at any point on the ground, with little to no countermeasures available. Whether "rogue hackers", or actual owners of the station, somebody would have the capability to destroy, without warning, large swaths of infrastructure on the ground. I sure hope I'm very wrong about this - that somebody have figured out a way of inherently neutralizing the danger. But for now I treat the project as a doomsday weapon in space. -- [1] the later is a given to an extent, due to the need for orbital stationkeeping, and only possible to limit via provision of weak engines and/or limited fuel loadout
- adrianN 8y agoIt's a pretty shitty weapon because many countries have the capability to launch a bomb to the satellites and the satellites are way more expensive than the bomb.
- gotocake 8y agoDepending on how close it is, you could destroy or at least damage the sattelite without even needing to launch anything. As a weapon, it would be downright silly to threaten a major world power with it. Of course if your goal is just to terrorize countries and groups without a space program, and assuming (big assumption granted) that other countries don’t interfere, then it would be a fairly exotic way of terrifying people. VERY expensive though, and diverting it from power generation to “kill” mode would be even more expensive. All told, a country that could use this as a weapon doesn’t need to use this as a weapon.
- rurounijones 8y agoAnd this is how we end up with https://en.m.wikipedia.org/wiki/Kessler_syndrome https://en.m.wikipedia.org/wiki/Kessler_syndrome
- DennisP 8y agoA year ago I read the book The Case for Space Solar Power, which goes into the engineering in detail. The old SPS designs from the '70s were monolithic beasts that would have been ridiculously expensive. Current designs would use a large number of identical parts, of about eight types, which would self-assemble in space. That way they can be mass produced in factories. The basic design was PV with microwave transmission, which has already been tested over distances of ten kilometers or so. (Iirc it was between a couple Hawaiian islands.) The receiving station sends a sort of homing signal for a phased array transmitter, which makes it difficult to redirect to somewhere without the homing signal and keep a reasonably focused beam, though you could switch between multiple receiving stations (which are fairly cheap). The station would be in GEO. The book did some detailed cost analysis and found that with pre-SpaceX launch costs, the SPS could provide power at 15 cents/kWh retail. Elon Musk has said that at scale the BFR could ultimately get to a $50/lb launch cost, so for grins I plugged that number into the book's calculation and got 4 cents/kWh. Since this type of solar would work through the night, with little or no need for storage, it could be pretty competitive. book: https://www.amazon.com/Case-Space-Solar-Power-ebook/dp/B00HNZ0Z96 https://www.amazon.com/Case-Space-Solar-Power-ebook/dp/B00HN...
- AstralStorm 8y agoIt would be competitive, if there were no nuclear power or maintenance costs or manufacturing costs. These are not counted in launch costs. You have to launch replacement panels pretty often due to trash collisions or put them in a less than convenient orbit. The space solar module with a good enough battery and emitter would cost about as much as half a radiotelescope... Because it is one. And consider we have problems covering sizable area with wires and cheap panels which are easy to maintain.
- DennisP 8y agoThe costs I quoted include everything, including manufacturing and maintenance. The book breaks down all these costs. In the 4 cents/kWh scenario, launch isn't the dominant cost anymore, and dropping that further wouldn't make much difference. You don't put a battery on a solar power satellite. To whatever extent you need battery, you put it on the ground, but you don't need much because a satellite in geosynchronous is in full sunlight almost all the time.
- thecopy 8y agoHow would they prevent overheating?
- electricityUser 8y agoHow do satellites prevent overheating? Radiators!
- fredley 8y agoWith regards to climate change and global warming, what about putting this in between the sun and the earth to block some of the energy reaching the planet to allow it to cool?
- fouronnes3 8y agoaka geoengineering. The latest IPCC report is quite critical of it.
- GistNoesis 8y agoI did a quick search on the Energy Returned on Energy Invested calculations. The following site https://dothemath.ucsd.edu/2012/03/space-based-solar-power/ https://dothemath.ucsd.edu/2012/03/space-based-solar-power/ gave an ERoEI of 10:1 for solar panels on earth vs ERoEI of 4.2:1 for solar panels in space. Which would indicate that we would still be better laying solar panel on the ground as long as we got the appropriate empty space. What did I missed? Have we realized enough progress since 2012 energy-wise, that the threshold has been crossed, or does it only make sense economically due to lower launch prices.
- adrianN 8y agoSolar panels in space also work during the night and while it's cloudy. Did your calculation include the energy costs of storage?
- AstralStorm 8y agoYou do know that one can build the panels on the other hemisphere, right? It is all a small matter of building a long enough high voltage DC line. Mostly a political problem. Or you can use microwaves on ground if it is easier to build a bunch of antennas. Ultimately also reflect off space mirrors (meshes) for much cheaper. The main problem is theoretically weather. Space has the other kind of weather called space junk.
- adrianN 8y agoHVDC lines are really neat tech and I fully support solar farms in the Sahara to supply Europe, but I wouldn't be surprised if it's cheaper to launch satellites than to build a global power grid that can provide solar power over night. I think debris is not a terrible problem right now. We manage to have a large number of satellites in high orbits.
- clojurestan 8y agoI would use this to mine cryptocoins in space, it's way easier to send information back to earth than power
- izzydata 8y agoIf there is a beam of energy being transferred from space to the surface will it be visible? Edit: Apparently this is a stupid question, but I still don't know the answer.