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ducttape posted:Also, the gravity well isn't so much of a problem. The gravity well of Mars is 1/4 the depth of Earth, and the Moon is 1/20. Plus, as neither of them have the thick atmosphere of Earth, catapult systems become significantly more viable. Humans likely can't survive in 1/4th gravity and definitely not in 1/20th for extended periods of time. A space station can simulate 1G. This reason alone makes space based colonies much more reasonable. The 1/20th gravity makes the moon a great place to mine though. The lunar regolith is made up entirely of oxides and contains large amounts of Aluminum, Iron, Magnesium, and Titanium. A space based colony is also always bathed in much higher concentrations of solar radiation, unlike a planet that has a day/night cycle and an atmosphere. Energy would be almost free. Mining space is also much more profitable than the surface of a planet. All of those exotic metals we love so much in industry are from meteor impacts. Why not just go to the source? http://www.livescience.com/15938-earth-precious-metals-space-origin.html
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Apr 22, 2014 08:04
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They're also from radioactive materials decaying. I've gathered there's a lot of rare earth minerals we could exploit, but we'd essentially be mining uranium or thorium to do 'em, and that will instantly cause nuclear winter and kill everyone. 
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Apr 22, 2014 08:09
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Rutibex posted:Mining space is also much more profitable than the surface of a planet.
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Apr 22, 2014 08:11
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It'd be more reasonable, and correct, to say that there are vast amounts of readily available platnum groups metals, we think, in gigantic and relatively pure chunks. So it's not terribly unreasonable to say that if you could grab and harvest them, the potential returns outstrip that of a differentiated body. This isn't a terribly controversial notion.
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Apr 22, 2014 08:18
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The Protagonist posted:It'd be more reasonable, and correct, to say that there are vast amounts of readily available platnum groups metals, we think, in gigantic and relatively pure chunks. So it's not terribly unreasonable to say that if you could grab and harvest them, the potential returns outstrip that of a differentiated body. I also really don't like the idea of companies tossing multi-billion ton rocks around in near Earth space, but I may just be paranoid.
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Apr 22, 2014 08:27
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You're still thinking about it through the lens of rarified use. Nobody knows what a goods economy looks like when platinum, iridium, palladium and the like are cheap and plentiful as tinfoil. Nevermind all the immediate benefits we can imagine, there are applications people haven't yet dreamed of.Rent-A-Cop posted:I also really don't like the idea of companies tossing multi-billion ton rocks around in near Earth space, but I may just be paranoid. The Protagonist fucked around with this message at 08:37 on Apr 22, 2014 |
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Apr 22, 2014 08:31
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The Protagonist posted:You're still thinking about it through the lens of rarified use. Nobody knows what a goods economy looks like when platinum, iridium, palladium and the like are cheap and plentiful as tinfoil. Nevermind all the immediate benefits we can imagine, there are applications people haven't yet dreamed of. Barring a revolution in lift technology any search and retrieve mission for a giant shiny asteroid is going to require an enormous investment up front. Someone is going to ask what exactly you want to do with their several hundred billion dollars and "gently caress knows! I'm sure we'll think of something" isn't going to be the right answer.
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Apr 22, 2014 08:38
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Re-usable rockets would be your lift revolution, and bright people are plugging away at that as we speak. It won't be easy, but there's nothing to indicate it should be unfeasible. That cuts your price to orbit to a tenth of what it was immediately. As for the latter, Larry Page and friends have already seen fit to start throwing some early pocket change at the problem, archaic horse-cart metaphor be damned. No one is seriously considering this and thinking they'll be making next-quarter profits, but to just dismiss it all out of hand because "nobody needs a hundred tons of platnum!" is naive. Right now we're probably looking at at least twenty years of thorough surveying and target claims, while we deplete the easily accessed minerals in the crust, the legislature figures out how to handle space-mineral rights, NASA figures out the fine details of redirect, and SX continues to improve and drive down the price of lift. Perfecting narrow-band optical communication is an ongoing must too. Basically people need to stop equating really difficult with impossible. The Protagonist fucked around with this message at 08:51 on Apr 22, 2014 |
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Apr 22, 2014 08:49
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Rutibex posted:Humans likely can't survive in 1/4th gravity and definitely not in 1/20th for extended periods of time. And as far as i know we don't really have any solid idea of what lower gravity will do to the human body since we don't have anywhere that is between 1g and 0g. I'd be happy if anyone has good links on that topic.
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Apr 22, 2014 14:41
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Rent-A-Cop posted:Basically I think you're putting the cart before the horse. This would be a lot more convincing if SpaceX didn't just dock with the ISS for the fourth time, for literally no good reason.
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Apr 22, 2014 15:33
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Actually, the problem here is analyzing space economics from the vantage point of seeing how capitalism and entrepreneurship might drive its initial first steps. I think this is a mistake. There is no way that venture capitalism will drive the off-worldization (is that even a word??) of industry, because it simply isn't profitable. What needs to happen for space industry to take off is massive government investment. Simply put, government needs to set up industry and infrastructure in space before any kind of profitable economic activity is to begin. What should be thought about is the economics of space, rather than the economics of getting into space-- how activities such as asteroid mining and manufacturing can be profitable when all of the operations have already moved off-world. It's ludicrous to imagine that we'd be paying to ferry workers, materials, and so forth off-world every day that our space steel factory is in operation-- all of it needs to be in orbit already. At that stage, operations in space can simply export its products back down to earth. All of the input-ends needs to be off-world, with just the output being sold back on the planet.
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Apr 22, 2014 15:44
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Eh, aren't tech billionaires like Brin and Musk throwing tons of money as well as sourcing for VC money for longterm oriented space projects? SpaceX is a good example of this.
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Apr 22, 2014 15:59
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Bistromatic posted:And as far as i know we don't really have any solid idea of what lower gravity will do to the human body since we don't have anywhere that is between 1g and 0g. I'd be happy if anyone has good links on that topic. We have a pretty good idea of what extended stays in microgravity does. It's not quite the same as being on the surface of a planetary body with lower gravity, but I don't think there's any reason to suspect the results wouldn't be intermediate between being earth-bound and in uG. There's a review of NASA's bone data here: http://onlinelibrary.wiley.com/doi/10.1002/jbmr.1948/pdf
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Apr 22, 2014 16:03
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shrike82 posted:Eh, aren't tech billionaires like Brin and Musk throwing tons of money as well as sourcing for VC money for longterm oriented space projects? Yeah, for developing tech patronage is a potential system, as it's basically a rich guy attaching their name to some discovery. Actual propagation of that technology would probably require massive government investment though.
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Apr 22, 2014 16:17
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computer parts posted:Actual propagation of that technology would probably require massive government investment though. Which in our age where anything outside of military spending is shat upon as waste and supporting the takers of society, I doubt we are going to see any government intervention without massive upheaval from the status quo. Once we beat the filthy commies to the moon  , most of the country lost interest and considered the space program to be wasteful. It will happen just like this with every other Space program until someone makes it cheaper or a new boogieman shows up. Besides, as other posters have stated there are much more pressing matters to address before considering continuing the human experiment on a grander, more galactic scale, and almost all of it involves efficiency. Getting the most out of the least on earth would lay the groundwork for what we will need to do in space. Hell we can't even store the meager energy we do get efficiently. So many green projects fail because any juice we obtain from those sources either takes to long or can't hold enough of charge to get things done. Until those issues are addressed, might as well enjoy Earth because this is where we are staying.
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Apr 22, 2014 16:31
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shrike82 posted:Eh, aren't tech billionaires like Brin and Musk throwing tons of money as well as sourcing for VC money for longterm oriented space projects? Those guys are trying to provoke God. We should hurry up and put a stop to this: https://www.youtube.com/watch?v=t9rXISqwEKM
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Apr 22, 2014 17:25
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The Protagonist posted:It'd be more reasonable, and correct, to say that there are vast amounts of readily available platnum groups metals, we think, in gigantic and relatively pure chunks. So it's not terribly unreasonable to say that if you could grab and harvest them, the potential returns outstrip that of a differentiated body. Pt-group metals are fantastic, wide-ranging catalysts. Cheap platinum would mean we wouldn't have to waste boatloads of cash developing cheap+crappy catalysts, or energy trying to force unfavorable reactions. It'd be a big loving deal. One issue is, what's the supply chain for these metals? Do you send the entire asteroid to a central processing facility in another orbit? Mine it there, send the purified metals to a smaller central processing facility? Or make final products on-asteroid? I would bet that the decision would come down to development of energy storage and process scaledown in the next hundred years. Your major energy requirements are asteroid/metal/product movement back to Earth/space station, vs energy cost of metal separations and processing. Ideally you wouldn't want to send a bunch of useless waste rock into earth orbit, just platinum/other metals.
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Apr 22, 2014 17:29
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Mofabio posted:Do you send the entire asteroid to a central processing facility in another orbit? Mine it there, send the purified metals to a smaller central processing facility? Or make final products on-asteroid? Literally de-orbit the whole thing back down onto the Earth. 
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Apr 22, 2014 17:31
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DrSunshine posted:Literally de-orbit the whole thing back down onto the Earth. I wonder how many de-orbited asteroid kg's it would take to shorten the length of the day by a few minutes. Wouldn't that also require huge rockets for deceleration? To counteract gravity, you'd need a force equal to the mass of the asteroid * 9.8 m/s^2. For a 1km diameter asteroid with a density of 2 g/cm^3, that'd be 1e13 newtons. A Saturn V puts out 3.4e7 newtons so I think you gotta process it in orbit. edit: put another way, the max asteroid diameter one could gently lower to earth is 15m. ((((15 m) / 2)^3) * pi * (4 / 3) * (2 (g / (cm^3))) * (9.81 (m / (s^2)))) = 3.4e7 N Mofabio fucked around with this message at 18:32 on Apr 22, 2014 |
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Apr 22, 2014 18:28
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Obviously there are a ton of options that'll become more or less favorable as necessity dictates, but my favorite form of hypothetical mineral delivery is to print the pure stuff out in a great big, low density 3d mesh and just drop it on the salt flats. The payload is the break.
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Apr 22, 2014 18:30
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Mofabio posted:I wonder how many de-orbited asteroid kg's it would take to shorten the length of the day by a few minutes. As for deorbiting I think this is actually somewhere where they have a pretty established concept: They'd collect the trace water and oxides and generate rocket fuel. They wouldn't need a whole ton of it for each payload since it'd mostly be controlled crashing in a shallow sea or something.
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Apr 22, 2014 18:30
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The Protagonist posted:Obviously there are a ton of options that'll become more or less favorable as necessity dictates, but my favorite form of hypothetical mineral delivery is to print the pure stuff out in a great big, low density 3d mesh and just drop it on the salt flats. You start running into Stokes law issues though as you scale a 3D mesh volumetrically though. The drag force needs to equal force due to gravity, but Stokes Law scales linearly to radius, and the force due to gravity scales to radius^3. It's a cool idea though. edit: if you print it as a roughly 2D mesh instead of a 3D mesh, you'd scale to radius^2, which would make it slightly less hard. edit2: and there's obviously no rule that says you need to send everything down in a single payload. Stokes Law is something to keep in mind for the payload optimizers, I spose. Mofabio fucked around with this message at 18:40 on Apr 22, 2014 |
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Apr 22, 2014 18:36
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Wow.  I had mostly made that statement as a "Drop asteroids on Earth for fun and $$$" joke, but I had no idea that that had been floated as a legitimate idea for asteroid mining. Awesome!
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Apr 22, 2014 18:47
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It'd be like a bigger version of this:
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Apr 22, 2014 18:52
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My feeling though is, if you have energy generation capabilities in LEO to: 1. reverse O2-H2 combustion for rocket fuel at something like 7 kJ/g water, which is a fat, fat reaction to reverse 2. do your metal separations in LEO, also energy (and solvent) intensive 3. have energy to melt the metal in a 3D printer in LEO (some combination of this and item 1) then you might as well park your mining operation and 3D printers in the asteroid belt/your near-earth asteroid's orbit, and just send pure metals, or even final products, home. Changing orbits of a bunch of rock you don't need is pretty energy intensive, and it'd make sense if we hadn't developed 1-3.
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Apr 22, 2014 18:54
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Considering the current attitudes toward climate change, I think that we will first develop enclosed, self-sustaining habitat structures on earth out of necessity for survival after most of the planet has been rendered inhospitable. Space colonies will then just be an afterthought of reconstructing those habitats in space (the silver lining to our 'inaction towards climate change' cloud). Re: asteroid mining, I think the harvested resources should be kept up in space and used to further develop and expand LEO habitats and ships for further exploration/mining rather than sent down to earth. As has been mentioned earlier in the thread, adding too much mass to the earth is going to change the physics of our orbit and rotation, so I'd rather err towards safety and keep everything harvested in space in space.
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Apr 22, 2014 21:40
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karlor posted:Considering the current attitudes toward climate change, I think that we will first develop enclosed, self-sustaining habitat structures on earth out of necessity for survival after most of the planet has been rendered inhospitable. Space colonies will then just be an afterthought of reconstructing those habitats in space (the silver lining to our 'inaction towards climate change' cloud).
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Apr 22, 2014 21:42
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karlor posted:Re: asteroid mining, I think the harvested resources should be kept up in space and used to further develop and expand LEO habitats and ships for further exploration/mining rather than sent down to earth. As has been mentioned earlier in the thread, adding too much mass to the earth is going to change the physics of our orbit and rotation, so I'd rather err towards safety and keep everything harvested in space in space. This is a concern on the same order of "well any atmosphere we add to mars just be swept away!", which is to say a very, very distant issue.
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Apr 22, 2014 21:59
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karlor posted:Considering the current attitudes toward climate change, I think that we will first develop enclosed, self-sustaining habitat structures on earth out of necessity for survival after most of the planet has been rendered inhospitable. That is completely crazy! Not even the worst runaway greenhouse effect models predict "Venusian Earth" as a potential outcome. And, while the predicted ~1-2 m of sea level rise is going to be tragic for low-lying nations like the Polynesian islands and Bangladesh, it would take more than a thousand years to completely melt Greenland and Antarctica under an extreme, worst-case catastrophic "methane clathrate burst" (i.e. Paleocene Eocene Thermal Maximum II) scenario to create a "Drowned coastline/semi-Waterworld-like" scenario. Abrupt climate change is a very real and very grave concern for our civilization for the next 200-odd years, but it won't make the Earth so inhospitable to such a degree that we'd have to live in sealed domes. karlor posted:Re: asteroid mining, I think the harvested resources should be kept up in space and used to further develop and expand LEO habitats and ships for further exploration/mining rather than sent down to earth. As has been mentioned earlier in the thread, adding too much mass to the earth is going to change the physics of our orbit and rotation, so I'd rather err towards safety and keep everything harvested in space in space. We'd need to add a tremendous amount of mass to the earth for this to be a conceivable issue. Remember that the earth is 5.97219 × 10^24 kilograms! v- EDIT -v karlor posted:Yeah, I should have been more specific. I'm not expecting a post-apocalyptic desert earth, just a situation where conventional open-air farming is considered too risky due to greater seasonal fluctuations in temperature negatively impacting crop yields. This would lead to developments and mass-implementation of hydroponics, and why not just build those facilities in or near urban centers to reduce transportation costs. While my initial framing might have been a bit dramatic, I think that what I just mentioned is definitely possible within the near future (if only for the transportation costs argument) v- Ahh, okay, that makes a bit more sense. -v DrSunshine fucked around with this message at 22:07 on Apr 22, 2014 |
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Apr 22, 2014 22:01
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Nessus posted:I don't think even the more pessimistic visions of climate change will be necessitating hab domes, although I suppose the Caves of Steel may eventually be preferable to dealing with all this weather bullshit. Yeah, I should have been more specific. I'm not expecting a post-apocalyptic desert earth, just a situation where conventional open-air farming is considered too risky due to greater seasonal fluctuations in temperature negatively impacting crop yields. This would lead to developments and mass-implementation of hydroponics, and why not just build those facilities in or near urban centers to reduce transportation costs. While my initial framing might have been a bit dramatic, I think that what I just mentioned is definitely possible within the near future (if only for the transportation costs argument)
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Apr 22, 2014 22:01
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DrSunshine posted:We'd need to add a tremendous amount of mass to the earth for this to be a conceivable issue. Remember that the earth is 5.97219 × 10^24 kilograms! Yeah something like 30-40.000 tons of dust lands on Earth every year and we seem to be doing fine in spite of it.
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Apr 22, 2014 22:40
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Anosmoman posted:Yeah something like 30-40.000 tons of dust lands on Earth every year and we seem to be doing fine in spite of it. Maybe that's the *real* cause of climate change! 
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Apr 22, 2014 22:44
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karlor posted:Yeah, I should have been more specific. I'm not expecting a post-apocalyptic desert earth, just a situation where conventional open-air farming is considered too risky due to greater seasonal fluctuations in temperature negatively impacting crop yields. This would lead to developments and mass-implementation of hydroponics, and why not just build those facilities in or near urban centers to reduce transportation costs. While my initial framing might have been a bit dramatic, I think that what I just mentioned is definitely possible within the near future (if only for the transportation costs argument) Yeah, and just to put numbers on it, the model median in the most recent IPCC estimated crop declines by 2100 of 15%. That's under 'business as usual' CO2 emissions, which so far, we've exceeded smashingly. To re-rail the thread, I agree that there might be technology overlap between space habitation and climate change mitigation. Earlier I pointed to energy efficiencies with combined power generation/chemical generation, requiring scaled-down chemical plants that are pre-requisites to long-term space colonization. There's also the more mundane solar panel manufacturing stuff, as well as enhanced plastic recycling (the ISS now has a plastic filament 3D printer, but no plastic recycling system yet for some reason). NASA is also working on an electron beam metal 3D printer, which can also be used as a metal recycler with a bit more effort. You mentioned hydroponics - that's also a point of NASA research. Cool stuff! The two common threads for all these technologies are 1) energy efficiency, and 2) miniaturization of world-scale facilities. I think 2) is the one with the most potential to change life on earth, but that's a topic for another thread.
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Apr 22, 2014 22:57
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TerminalBlue posted:Between getting Earth's poo poo together and starting a sustainable space colony, I'm going to say the latter is much more realistic and far cheaper. How do you estimate the cost of a sustainable space colony (whatever that is)
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Apr 23, 2014 02:20
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down with slavery posted:How do you estimate the cost of a sustainable space colony (whatever that is) They did a documentary about this, put a bunch of people in a completely sealed off biohabitat. Some sort of dome.
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Apr 23, 2014 02:27
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Here's a Wikipedia article on an old biodome experiment: http://en.wikipedia.org/wiki/Biosphere_2 The challenges section was the most interesting for me. Really goes to show how far we've come in such a short time period.
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Apr 23, 2014 04:31
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Cheekio posted:They did a documentary about this, put a bunch of people in a completely sealed off biohabitat. Some sort of dome. Yeah and it failed miserably. This is on earth where you just get gravity for free. The idea of building a "sustainable" space habitat (no supplies necessary from the outside?) is literally insane and anyone talking about the "cost" of such a thing is full of poo poo. It would be easier to go underwater than it would be to go into outerspace. Colonizing antarctica would be easier. WHY would we ever go to space? It just makes no sense to send people in to outer space given what we know at this point. It's some kind of hold on to the dream that star trek is around the corner or something. It's not.
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Apr 23, 2014 05:31
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Kristler posted:Here's a Wikipedia article on an old biodome experiment: That experiment also lead to far worse horrors then the world has ever seen http://en.wikipedia.org/wiki/Bio-Dome.
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Apr 23, 2014 05:43
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down with slavery posted:Yeah and it failed miserably. This is on earth where you just get gravity for free. The idea of building a "sustainable" space habitat (no supplies necessary from the outside?) is literally insane and anyone talking about the "cost" of such a thing is full of poo poo. Well, at some point we might want to expand beyond our solar system, so it might be good to figure out how to live in space to a certain extent.
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Apr 23, 2014 05:47
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down with slavery posted:Yeah and it failed miserably. This is on earth where you just get gravity for free. The idea of building a "sustainable" space habitat (no supplies necessary from the outside?) is literally insane and anyone talking about the "cost" of such a thing is full of poo poo.
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Apr 23, 2014 05:51
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