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Future of Space Elevator Looks Shaky
lurking_giant writes "In a report on NewScientist.com, researchers working on development of a space elevator (an idea we have discussed numerous times) have determined that the concept is not stable. Coriolis force on the moving climbers would cause side loading that would make stability extremely difficult, while solar wind would cause shifting loads on the geostationary midpoint. All of this would likely make it necessary to add thrusters, which would consume fuel and negate the benefits of the concept. Alternatively, careful choreography of multiple loads might ease the instability, again with unknown but negative economic impacts."
The engineering required for this elevator is mind boggling. After witnessing the amount of time and effort that went into a small suspension bridge spanning the river Thames in London (The Millenium Bridge), the mere idea of this elevator scares the shit out of me.
When it came down to it the space elevator though nice, is a dumb idea. Like the jet pack. Think if the resources needed to defend it from terrorists, or maintenance costs. Seemed also like a put all your eggs in one basket as well I mean we would be much better off to just improve our propulsion ability. Personally i like a rocket powered mag-lev launch vehicle, that would travel down a rail that ends up pointing to the sky.
Most of the inner planets have no space elevator at all; Venus and Mercury because their days are unfeasibly long, Earth because its gravity well and debris belts challenge the limits of engineering.
Look where all this talking got us, baby.
Corrolis force problems were one of the first things I thought of when I first heard about the space elevator, but I'd never seen the issue brought up.
It's a given that a elevator would be tethered at the equator, thus will be traveling at 1600kph, the velocity of geosynchronous orbit is what, 11000kph? Anything climbing from the bottom up will be accelerated to that as it ascends. So the question is how the hell do you mitigate this without literally bending the thing out of shape - burning fuel is silly It's not a trivial velocity, it's 40% of what would put you into LEO orbit anyway!
Despite this, I don't think this is a showstopper, remember Arthur C Clarke told is it will be built...
After logging in slashdot still does not take you back to the page you were on. It's been that way for 20 years.
Very amusing indeed.
Especially since Kim Stanley Robinson wrote his "Red Mars" series & specifically addressed these issues. He correctly identified the problems, and came up with very realistic solutions.
Yes, the orbital section had to have thrusters to combat what is mentioned in the article.
He also determined that the 'elevator' portion would require significant advances in materials, and require a futuristic substance that could withstand the sheer loads & twisting due to wind, atmosphere, etc.
He even took it to the point of examining what happens when the terrorists from Earth blow up the link cable that connected the orbital portion, resulting in the elevator 'crashing' down to Mars. He even correctly showed how it would actually wrap around the planet (as opposed to falling straight) and when the final piece impacted it caused a huge crater from the sheer kinetic energy. (like a whip-lash).
Good stuff. Maybe these 'scientists' should bother to read once in a while, they might save themselves quite a bit of time. Of course, that would mean budget reductions, so they probably wouldn't have bothered anyhow.
I told everyone it wouldn't work. But would they laugh at me? No!
I know you were joking, but I really think it won't work for reasons not specified in the article. It's such a simple reason that I can't believe it's so rarely mentioned or addressed.
The earth is built very much like a capacitor. The ground has a fairly strong positive charge and the ionosphere has a fairly strong negative charge, with an insulating layer of air in-between. Carbon nanotubes can conduct electricity; so can most other materials I have heard of that would be used for a space elevator. I imagine that any conductor (and possibly dielectrics also when you consider electrical breakdown and the sheer current involved) would vaporize as soon as this circuit is closed. Coriolis forces and weight distribution and whether thrusters would be necessary seems trivial by comparison.
It is a miracle that curiosity survives formal education. - Einstein
If the reason for coming with such a thing as a space elevator(which I agree is pretty impossible with any material currently known) is to cut down on the cost of getting things into space then why hasn't anyone been looking to build a "supergun" like Gerald Bull had experimented with ages ago? It just seems logical that if you built it at the equator you could cut down on fuel required by using a gun style launch and then having the thrusters kick in at the top of the arc and use the momentum to assist getting the vehicle into space. And if we could build it as a magnetic coil or rail gun we could save even more by using electricity, which is easier to produce, than chemical engines.
So is there anyone looking at the "supergun" concept? or did the idea die out with Bull?
ACs don't waste your time replying, your posts are never seen by me.
The earth is built very much like a capacitor...
So use the current flow. You're breaking the earth's magnetic field lines with the cable. Not a lot of field strength, but it's a lot of field, sounds like a generator to me. Ship up the necessary kilograms of (i don't know, zinc perhaps) sacrificial anode and dump the potential via ions accelerated as lateral thrusters running continuously, and vary the flow in any particular direction to adjust the position of the cable terminus. The spare current could run the elevator cars.
Do not mock my vision of impractical footwear
People who don't know, or who refuse to accept that things are 'imposible'. They're the ones who drive progress. Think the Wright brothers, Einstein or better still Michelangelo, who imagined flying machines and submarines that were only inviable because the necessary technology (engineering & materials) were not available.
After all, geosync orbits were thought up by first by a scifi writer...but to your point, Arthur C. Clarke did have a good grasp of Physics...
The space gun concept would really only be good for a very narrow range of payloads that can withstand the extreme g-forces produced by such a device. You can reduce the g-forces by using a longer barrel but it's still a concept that really isn't feasible.
What we should be looking at is a Space Fountain. Yes, it seems like a very odd idea but it's backed by a lot of very good science and a lot of people are saying that it can be done with present materials and technologies. At the very least we should be experimenting with them on a smaller scale, using them to erect temporary masts and towers.
Sapere aude!