We have the engineering capabilities, and materials science to pull it off currently. We just don't have the mass production capabilities or quality control for the materials nor the massive amount of infrastructure and and capital needed to actually do it.
Fusion power is an endless pipe dream and R&D money pit that likely will never come to fruition in a meaningful or reliable positive output way. We don't have the technical knowledge nor the materials science necessary.
>>6661530 >space elevator >decades long construction project based on highly automized techniques we don't currently have for materials that are just past theoretical. >could easily fail catastrophically laying complete waste to what would be the single largest human endeavor in the history of anything. >satellites and space debris exists all along it's projected length that would completely assfuck it in every way imaginable that is nearly impossible to clean up.
>fusion power >theoretical pipe dream requiring a fuel we don't have easy access to, indestructible unobtanium containment materials that don't and likely cannot exist, the ability to completely harness and shape magnetic fields in a precise and energy expensive fashion that we don't know how to/can't do.
Kinda funny though that realistically to supply the sort of energy output to make a space elevator possible/practical, you pretty much need high output fusion power. At the same time to make the development and fueling of fusion power practical and possible, you need a space elevator.
>>6661590 >a fuel we don't have easy access to The only fusion fuel we don't have in abundance is He3 > indestructible unobtanium containment materials An airtight steel vessel in partial vacuum and magnetic bottle is unobtainable? >the ability to completely harness and shape magnetic fields in a precise and energy expensive fashion that we don't know how to/can't do. we can shape magntic fields well enough, unfortunately super-hot plasma is ill behaved and bleed energy through various exotic mechanisms.
We can create fusion reactions in the lab with ease, what is lacking is reaching densities where output exceeds input.
>>6661610 >how small can we make a star. A modern thermonuclear warhead is ~800kg.
A star however uses gravitational compression which is entirely unfeasible for anything less massive than a star.
It's not all that hard to achive the energies required to fuse particles, what's hard is to do so in an energy-economical manner that ensures the energy output is positive after factoring in conversion losses and the energy used to sustain the reaction itself.
In terms of hardware it's probably much easier to use a shot-based approach than some steady state plasma tokamak.
>>6661596 Fabricating nanotubes on an extremely large scale remotely Lifting production assembly literally into orbit Materials handling and infrastructure for massive amount of raw materials being 'pumped' into orbit Infrastructure of moving the base of the elevator. All the power for actually operating the thing.
Massive amounts of power necessary, and it has to be produced nearby the base for tippytop efficiency, likely in the middle of the ocean.
>>6661606 >The only fusion fuel we don't have in abundance is He3 He3 is exactly what we would need to mine in space.
>An airtight steel vessel in partial vacuum and magnetic bottle is unobtainable?
Every successful fusion experiment to date has required complete overhaul of the containment vessel and material after even short term events.
>we can shape magntic fields well enough, unfortunately super-hot plasma is ill behaved and bleed energy through various exotic mechanisms. We cannot shape them well enough to fully contain the reaction to the point of preventing containment damage.
>>6661631 >He3 is exactly what we would need to mine in space. It's only benefit is that its aneutronic. >Every successful fusion experiment to date has required complete overhaul of the containment vessel and material after even short term events. That's because they are fusion experiments and overhauls are part of the optimization and experimental procedure. If you mean "due to damage": citation needed >We cannot shape them well enough to fully contain the reaction to the point of preventing containment damage. We can, it's easy, containment damage is a constant risk in fusion projects but it's by no means considered a dealbreaker.
>>6661728 We know carbon nanotubes could do it. We just haven't been able to create long enough yet. We know it is possible in the same way we know fusion power is possible. Fusion is a lot more complex a problem though. That's why so much funding is going into it.
>>6662628 Space elevators will never be a reality. It's a very stupid idea. By the time we have the technoglocial capability to build it there will much better solutions to the same exact problem. Fusion, on the other hand, is incredibly useful and there are actual, serious efforts to make it real.
Firstly, He3 really isn't very useful. We're still quite some way from being able to practically exploit D-T fusion, and He3-He3 fusion is much, much harder.
Secondly, it's only marginally more abundant on the moon than it is on earth.
Finally, it can be manufactured using a number of fusion reactions (some of which are themselves aneutronic), which is likely to be a far more practical source than mining should we ever have a need for large quantities of the stuff.
In short, the only practical application of He3 is as a plot device for science fiction stories. As is typically the case, this can appear to be realistic, but only if you aren't particularly familiar with the science.
>>6661636 The only feasible place that this can be taken is in the equator and the ocean and even then it's probably a lot more complicated than that. Then you have the damn muslim terrorists who want to prove a point. Especially because this is reminiscent of the tower of Baal, there's no way the terrorists are going to leave this behind. And on that note you need to deal with climate and various shit that's orbiting earth and could knock out the elevator's weight thing out of geosynchronous orbit. There's probably a lot more than this as well.
>During a full D-T experimental campaign in 1997 JET achieved a world record peak fusion power of 16 MW which equates to a measured gain Q, of approximately 0.7. Q is the ratio of fusion power produced to input heating power. In order to achieve break-even, a Q value greater than 1 is required. A self-sustaining burning plasma requires at least Q=5 (since the alpha particles carry one fifth the fusion energy) and a power plant requires at least Q=10. As of 1998, a higher Q of 1.25 is claimed for the JT-60 tokamak; however, this was not achieved under real D-T conditions but extrapolated from experiments performed with a pure deuterium (D-D) plasma. Similar extrapolations have not been made for JET, but it is likely that increases in Q over the 1997 measurements could now be achieved if permission to run another full D-T campaign was granted. Work has now begun on ITER to further develop fusion power.
Daily reminder that JET can already produce net power and ITER will verify that a commercial fusion power plant is possible.Magnetic confinement fusion works perfectly fine and has advanced over the last 30 years into something that might actually work and probably will. there's absolutely nothig pipe-dreamy about it whatsoever.
>>6662657 The ocean is the obvious choice for it's base.
The only thing that would be limiting it's travel through orbit is things zipping around in or near LEO. Satellites and debris would need to be moved/removed if they posed a collision risk.
The entire area around the elevator would obviously need to be heavily regulated and fortified. With military flotilla (merika) and no-fly zone for several hundred miles.
Meteorological effects would be mitigated with sufficient size counterweight/tension. The counterweight itself would be easily adjusted/repositioned because of the relatively small orbital velocity past geosynchrous orbit and the resulting small amount of dV necessary to make corrections.
>>6662660 We are no where near able to create self sustaining fusion reactions yet and doing so IS a pipe dream. Such a thing is perpetually "30 years off" for the foreseeable future.
>>6662666 Based on the current/foreseeable geopolitical/economic climate, the united states of freedom would be an obvious majority contributor. But such a thing would doubtlessly be a multinational effort.
There would also need to be considerable motivation in terms of space development/travel to make such an effort worthwhile. Which there isn't which is why so much more money is being pumped into the possibility of fusion power. Because power demand exists and is increasing insatiably.
>>6662667 There has not been a full self sustaining reaction. There has been no actual energy positive reaction, only calculations that such a thing is possible on currently existing hardware and even if this energy positive reaction were carried out it is not self sustainable in any way.
>>6662677 space elevators are a cool idea, and I am sure will be used heavily on the moon and other none water rich areas, but on earth, once you have fusion you can put a few powerful lasers on earth and a few on some satellites and use steam rockets to get into space, water is free and non polluting and there is no easier rocket to design then a steam rocket, given a big enough rocket and powerful enough lasers, there is no practical limit to how much mass can be launched into orbit.
>>6662675 >There would also need to be considerable motivation in terms of space development/travel to make such an effort worthwhile.
This is always the problem I keep running into. Getting things down to earth is as easy as falling on your ass, but the elevator only makes sense if you're looking to get a lot of stuff out of the gravity well on a constant basis that is going to make a big enough return to pay back the massive investment of the space elevator itself.
Tourism and science ain't gonna finance that.
Asteroid mining seems to be the nearest potential goal that would justify a space elevator on a cost/benefit kind of way. Of course that is a whole different can of worms since the tonnage of resources we're talking about would pretty much smash the conventional economy.
It's like you don't even keep up with fusion energy at all /sci/. These guys are going to be replacing enormous power plants in a few years with these things. There's also at least two other small scale fusion efforts, one of which intends to replace combustion engines in vehicles.
>MFW I will live to see fusion-electric hybrid cars that get 3000 mpg
>>6663370 The ribbon, or tether, or whatever the form chosen, would still be damaged if hit with both great heat and a large mass moving at great speed.
Whether the line would break or not would need some calculations, but it would be damaged and would need repairs before regular traffic could continue.
Of course, there would already be systems for repairing the line, since it would degrade on it's own and replacing the whole thing wouldn't make economic sense.
Also, if the line was broken in any kind of altitude attainable by commercial aircraft, the mass of the tether above the cut would still keep the end close to ground, especially if more line was fed from the counterweight, where the machinery to make the whole thing would probably still be.
Actually, continuous feed of the line from space to ground might serve as regular maintenance in normal operations.
>>6663390 The construction method that seems most plausible to me would be launching (actually several launches) to put the initial geosynchrous station into orbit and start of the counterweight as well as prefabricated sections of the initial tether.
Then with the help of subsequent launches further prefabricated sections would be incorporated until the tether was able to reach low enough to be anchored. While this is all happening the counterweight/station is maneuvered relative to the structures center of mass.
Once it is anchored a 'crawling' fabrication facility takes up material to increase counterweight mass and being further reinforcing the ribbon to by fabricating the length to it's full diameter in order to support the full mass of the full operational weight of the elevator and counterweight.
May need to be done in several progressive steps with progressively larger fabricating crawlers to build up the eventual size of the ribbon without exceeding the capacity of the initial anchoring/counterweight/tensile strength.
>>6662635 >Space elevators will never be a reality. It's a very stupid idea. Asssuming plenty of fusion power it would probably be much easier to use space fountains/cables(active powered structures) instead of elevators.
>>6662612 while some estimates do say that we have some materials that could survive post construction, the construction would pose a major issue. This isn't something you can build with a crane, and does not have the kind of base structure to build floor upon floor.
>>6664093 No, no one ever suggested making the space elevator from the ground up (since victorian times, at least), but instead from the top down.
A regular suggestion is to catch a handy carbonaceous chondrite, steer it into the required orbit and produce the needed thread from it's mass and then lower the ribbon/tether/else down into the atmosphere and finally to the ground to be caught and fastened, while at the same time balancing it with an outgoing thread if/as needed.
And if the production process is perfected and cheap enough, you can keep the machinery going, producing strengthening/replacement thread as needed.
>>6664949 Except that it's not long enough to do that, when well placed it the pacific it probably couldn't even reach anything significant. That is not to say that the elevator itself isn't the most valuable object on the planet anyway
>>6661530 I'm going to say Fusion because I really don't know how a space elevator would be achieved depending on where it's going. The moon for example, you'd have to put it in such a way that it rotates between the earth and the moon to make it effective for the majority of time it can be accessed. Else you could plant it straight on earth and wait for the perfect moment everyday, but you'd definitely have to plan ahead and make it suitable for beyond high-altitude conditions. Also I'm not so sure how much pressure there'd be from leaving such a high altitude and going straight into zero-g, if there would be any. Though if anyone's got shit that can blow whatever I've said away, please do. Because I'd be pretty hyped for a space elevator.
>>6665038 I don't think you've seen newer x-ray imagers. There's almost no shielding required. Even the lead smocks attendants use are a holdover from safety policies dating back decades.
Capturing and converting x-rays around a small scale fusion generator (which is actually quite small when talking about powering an electric vehicle) is a relatively trivial engineering problem at this point. Nothing massive is required and that piece of it won't need to rely on new science or materials being developed.
Since a space elevator would be under tension at all times (both for stability/stationkeeping and to support the forces of scending loads) and be counterweighted, if the elevator shaft/ribbon/cable/whatever were damaged/broken it would want to fly off into space, not topple down to earth.
Of course whatever lower altitude portion of the break would fall to earth which is why locating it in the pacific would be the best bet. And since any portion of it that is below geostationary orbit would be at suborbital velocities the majority of it would conserve momentum and essentially fall straight down relative the earths surface.
The higher altitude portion that would tend to fly off into an elliptical orbit would be saved by the counterweight's stationkeeping propulsion (which it would have for normal operation/stationkeeping/alignment). From there it could be parked back into a untethered geostationary orbit and reconstruction of the damaged lower portion of the elevator could be performed.
>a whole thread jerking off to space elevators and fusion
Why bother with these far future technologies when we can design and build thorium nuclear reactors for cheap safe energy and mass drivers to get to low earth orbit for ($1/kg)? These are much more feasible technologies for the near future.
>>6668512 >16 billion >isn't expected to begin full deuterium-tritium fusion until 2027 In addition, it's still an experimental rector. Nuclear energy is a proven technology with more technical understanding.
Meanwhile in thorium: >India's government is also developing up to 62, mostly thorium reactors, which it expects to be operational by 2025. >first reactor expected to commence operation in two months Did I mention you can also mix in current nuclear waste (and thus dispose of it) to power them?
A space elevator would require a global worldwide-effort. Humanity is too selfish to focus on anything other than money. There's probably no benefits (yet) that would justify mobilizing that much ressources. Also, I think that nothing big can be done in space until we find a way to send humans and materials cheaply, rapidly and at a large scale, without any physical link to the Earth. I guess the most realistic way is building ships strong and reliable enough to be able to enter/exit atmosphere using its own propulsion methods.
But yet again, that would require some serious engine technology, aerodynamics constraints and an energy supply that doesn't exist yet.
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