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Stepping Closer To The Space Elevator
multicsfan writes "This article at Space Daily indicates that one of the major stumbling blocks against the space elevator has a potential solution. What do you make the elevator from? What's strong enough? It appears that carbon nanotubes may meet that requirement with a strength twice the minimum estimated." Now the problem is just getting a process that can get us from growing 4 mm in length to 47,000 km - I've got Wallace (and Gromit) working on it now.
Here's a link with some basic info about beanstalks (the 5 technologies required, etc...) and a link to the NASA white paper. This should help explain some of the questions I've seen posed here regarding the propultion of the elevator cars and the carbon nanotube requirements.
For example, I can understand the purpose of a counterweight. Not hard. Problem is, without knowing the numbers, it's hard to see what options are feasible or not. What mass are we talking about here (for the counterweight in space)? What force is required to get that mass up into space, if moving an asteriod is not a feasible option? Could the mass be replaced by an engine that always fires away from earth? How powerful of an engine would be required? While the suggestion of a large rock as a counterweight would be feasible, what other solutions may be feasible, e.g. could a nuclear engine provide enough thrust? What about a space sail (for the half or whatever time when the geosyncronous orbit allows a space sail to be used)?
Similarly, I'm wondering why an earth-based building is necessary. Does the end of the elevator/line actually have to be in contact with the earth, held? Could we carefully balance the line such that the need for a large building is necessary (this and past articles mention the huge buildings necessary)?
Yeah, what I'm aiming for is whether a continuously firing engine in space could act as an appropriate counterweight, and with enough control, be used to eliminate the need for an earth based building. Having a site with the numbers would be nice, so I could answer these on my own, and educate myself as to the details required to carry out this project. Yeah, I could have someone just answer these questions straight out, but I wouldn't learn anything consequential and maybe contributory in the process.
The main problem seems to be the amount of carbon to make the tubules.
Um, have you ever heard of coal? It is well over 90% carbon. Carbon is very abundant. The problem is growing nanotube fibers of sufficient length. The current processes for building nanotubes is completely slapdash. The result is black soot that the researchers must sort through to find buckyballs or nanotubes. I am sure people are working on more efficient manufacturing processes, but I haven't seen anything better yet.
Not just any elevator music... the muzak version of "Stairway to Heaven", over and over and over...
HSJ$$*&#^!#+++ATH0
NO CARRIER
I think you mean everyone with an ID over 500 is new :-)
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What our ancestors would really think, if they were alive today, is: Why is it so dark in here? (Terry Pratchett)
Yeah. 'cause that worked out just that way for that whole Panama Canal thing, right?
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Every year during my review, I just pray the words "slashdot.org" aren't mentioned.
Why hijack a commercial jet liner when you can send an orbiting base flying out of the solar system?
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Every year during my review, I just pray the words "slashdot.org" aren't mentioned.
If Libya built a space elevator, nobody else would do a goddamn thing, because Libya would have a huge advantage.
But the US is going to build one first.
And nobody else is going to be able to do a goddamn thing about it. (except the aussies, who will probably just pass an ordinance forcing all women to wear turtlenecks so the americans don't look down their shirts.)
These are my friends, See how they glisten. See this one shine, how he smiles in the light.
I would guess that though the main supporting member is 10cm thick at the base, there would be a vast infrastructure surrounding the beanstalk, and attached to the beanstalk all the way up, allowing more than one elevator to climb it at the same time.
Think bandwidth.
These are my friends, See how they glisten. See this one shine, how he smiles in the light.
At $1.50 per kilogram (for simplicity):
Cost for me to ride up: $163 USD
Cost for my wife to ride up: $78 USD
Cost of my wifes luggage to ride up: Twice the current national debt!!!
Remember the counter weight? It has to be going at the same speed as the elevator but is at a higher orbit so it would drag all the structure in space...
Black holes occur when God divides by zero.
I'm getting confused.
Wouldn't spliting it into stages reduce the likelyhood of it whiping the equator into a frenzy ?
--= Isn't it surprising how badly I spell ?
The other thing is that this elevator cannot be a direct lift into orbit. In order to work you need to break the climb into stages. The 1st would be a conventional aircraft up to a floating platform ( think 30 blimps in a cluster ).
The second and 3rd stages would also be blimp clusters but at increasing altitudes. That gets you well above the stratorfare and hence above weather etc... You then have the final hop to a low orbit satellite or space station...
Not as convenient as the original plan but this could possibly work without damage to the strand causing the whole thing to come crashing down in an unplanned manner ( Planing is key since the station would likely be bigger than Mir. If it comes down you better make sure it lands in the ocean. I can't imagine the kind of liability suite you would face for wiping out a small town.
PS: The individual stages could also tumble but spliting reduces both the risk and the extent of damage if it hapens.
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Quidquid latine dictum sit, altum viditur.
Whatever is said in Latin sounds profound.
--= Isn't it surprising how badly I spell ?
I read a really nice article about this in Popular Science YEARS ago.
-kidlinux.
Robinson himself admits that he was grossly over-optimistic in his timescale for terraforming Mars. Even with all the techniques he suggests, it would take several times longer. An interesting alternative I once heard about is the "world-house" (cf green house) a plastic skin holding down a km or so of breathable atmosphere near the surface, supported on pylons. Surprisingly, the physics can be made to work out without ridiculously strong materials, and the skin can be built progressively.
It's called a solar chimney, and they work with current technology, at least in pilot and demonstration systems. Large scale economics are another question, but it's possible. (Depending on efficiencies it may be worth covering the collector at the base with photovoltaics and just using the waste heat absorbed to drive a chimney.)
o la r%20chimney
9 2/ qid%3D950759721/sr%3D1-35/bargainsolarcom/107-9764 317-8756526
http://www.ccom.lk/energen/solrchmn.html
http://www.me.ufl.edu/SOLAR/chimney.html
http://www.google.com/search?client=googlet&q=S
http://www.amazon.com/exec/obidos/ASIN/39306986
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rant
I'm well aware of Boston's "Big Dig" Central Artery / Tunnel Project - I lived in Boston for many years & still contract there.
The $14 Billion of the "Big Dig" wouldn't cover the development & deployment of the spacecraft required much less their operation or the actual construction of the Space Elevator.
Good to see the old towne hasn't become any less provincial.
I don't read ACs: If a post isn't worth so much as a nom de plume to its author then I wont bother either.
Somehow I find that a very daunting list of requirements.
I'm not knocking the NEO idea, I'm just pointing out it's not a slam-dunk of a solution.
Please no one glibly answer "nanotechnology". Even if we could build the basic parts required there are still the command, control, and power-requirements of a nanotechnology-solution that promise to be at least as difficult as building the darn things. Answering "by clicking our heels together 3 times" would be as honest an answer at this point.
I don't read ACs: If a post isn't worth so much as a nom de plume to its author then I wont bother either.
Space Elevators work by orbiting synchronously with the Earth. Indeed due to their stationary nature they're often referred to as "beanstalks" (Jack and the...) There are other designs where they instead act as a giant rotating spar slicing down through the atmosphere and back up again but the most popular is where they're tethered (anchored is probably too strong a word) somewhere on or near the Earth's equator.
Many designs truncate the outer-end of the cable, instead substituting some sort of counterweight such a captured asteroid. For vertical transport sealed cabins would be used for passengers, unsealed would do for hardy cargo. The technologies wouldn't be very exotic, indeed they could be built today by anyway halfway competent Jr. Technical School.
Most designs have the cabins ascend & descend using electric motors (none using winches & cables found in the more traditionial elevators.) The motors themselves needn't be anything special, anything that can lift the cabin in 1G would do fine. Another alternative would be some sort of magnetic drive, Lawrence Livermore's Inductrak being one good candidate.
Power requirements would be fairly modest & using the electric motors as electrical generators on the down trip could recover much of the power used. A single large power station would be enough with today's technologies, or possibly several solar satellites using future technology.
However there are a couple of fundamental problems that are evident even from this far away.
- Carbon nanotubes have thus far only been created in very short lengths. Scaling them up hasn't been achieved yet.
- There isn't a good mechanism for bonding, braiding, or otherwise welding together the nanotubes.
- The mechanical, electrical & chemical properties of the tubes are still being studied. They may prove to be unsuitable for this application.
- Carbon is flammable, be it as lumps of coal or as diamonds or as nanotubes.
- However recently other materials then carbon have been formed into nanotubes so it may not be the only choice.
- We don't have a way to get the construction materials into orbit from where to begin building. An expansion of space shipping by several orders of magnitude for an extended period of time would be required to ferry up an elevator's components from the planetary surface.
- As others have pointed out the dangers of a disrupted elevator would be significant, indeed catastrophic.
- The financial investment in such a project would dwarf all other civil engineering to date. While the payoffs could well be incredible the risk would be great & the markets unproven.
Space Elevators may well indeed prove in the long term the best way to get between orbit & a planetary surface. However they're a way off in terms of materials alone not to mention finances & other practicalities. Even if we were to develop a magic fiber tomorrow with all of the necessary properties it would be several decades before we'd be in a position to use it. That said it's never too soon to start laying the groundwork.I purposely didn't look up & embed URLs into this: Clearly you're already online if you're reading this so paste the interesting bits into your favorite search engine and look up the nouns yourself.
I don't read ACs: If a post isn't worth so much as a nom de plume to its author then I wont bother either.
Fountains of Paradise (also by Clarke, but printed in 1979) centers around the idea of a space elevator.
It sure has, why, the US has never interfered with Panama since the canal handoff, no sir, never.
Except for that Noriega thing, but never again.
Hemos posted on this same topic just a few months ago...guess he forgot ;)
:)
You must be new here. Next you're going to complain about the spelling.
p;
This seems to go seriously against the Engineer's main goal:
To retire without having a major catastrophy associated with you.
Sometime ago I read an Arthur C. Clarke book, I think it was called "Fountains of Paradise", which talked about exactly this type of technology and how it would be used.
I think the possibilities presented by this technology could revolutionise our space exploration capabilities as well as supply high bandwidth communications in the form of a huge spiderweb antennae surrounding the earth. and we could use that pulse coded transmission technology from TimeDomain to power it.
What do you think?
When shit hits the fan get some of these https://youtu.be/pY-GncsZ-UE
At Mars it would work. On Earth, you need taper, because without it you would overwhelm the nuclear forces that hold matter together. There is no material possible that could support an untapered tether at Earth.
If tits were wings it'd be flying around.
what about India and China?
ELITISM: It's always lonely at the top. Uninvited company is rarely welcome.
A space elevator on mars would significantly decrease the cost of shipping materials back from mars.. Getting materials into space is the expensive part of the trip. Earths gravity will provide all the energy needed to get stuff down. And if your willing to wait long enough, the mars-earth part would be pretty cheep to.. So a inplace space elevator would decrease orbiting costs to close to nothing when its running..
My point is that in the future minerals and ores will be harder to get on earth, and we will be performing some extra-testeral mining, possibly on mars. And to get the rock of mars, a space elevator might be more economical then rocketry. And you dont need a elevator on this end, as getting things down is easy.
A few years back, John Storrs-Hall (for many years the moderator of sci.nanotech) was talking about an interesting idea that, like the space elevator, is not very far beyond existing material science. It is also probably more economical. The gist is an airport runway, 300 km long and at an altitude of 100 km, with a built-in linear motor that can accelerate a spacecraft. Over 80 seconds at 10 G, the craft accelerates to 8 km/sec, necessary to maintain a circular orbit. Humans (at least young healthy ones) can survive this acceleration. Current approaches to space launch cost around $10,000 per kilogram. The space dock could allow launches for 91 cents per kilogram, dropping to 42 cents per kilogram as the construction was amortized over the first few decades of use.
WWJD for a Klondike Bar?
There is a difference between can and won't. We can put a man on Mars 32 years after setting foot on the Moon, we just won't.
Mod down posts with a "Free Mac Mini/iPod" sig, they're spam!
Once you reach geosync height, you have orbital velocity provided "free" by the Earth's rotation. The geosync station isn't held up by the cable at all. The cable is held up by a counterweight just beyond geosync.
Read the article. It says a traditional pulley system isn't viable, but a maglev-style elevator might work (and could even generate electricity as the thing slows down).
Your analogy would worry me, if the problem was that some terrorist might suddenly stop the Earth from spinning. However, a better experiment might be to spin around with your bullwhip, and then suddenly let go of it. (even that isn't a good analogy though, as you aren't the primary gravitational force on the whip)
I don't care if it's 90,000 hectares. That lake was not my doing.
It's definitely something where the failure modes would need careful study. Build the first one on the moon. (Smaller, cheaper, easier, less useful...) Practice throwing spaceships at targets, catching returns, etc. Then build a pinwheel at earth (high in the stratosphere to space). Useful, but not as expensive, fewer worrisome failure modes, etc. Then build a beanstalk on Mars. Think of it as a scale model for one on earth, and design it accordingly. It will be more expensive than one designed specially for Mars, but as a prototype of the real one at Earth, the cost should all be written off. (I suppose that one could use Venus rather than Mars, but only chemical plants would want to visit Venus).
Then expand into the web between the worlds. Eventually an elevator to the stars. (I might prefer MacroLife.)
Caution: Now approaching the (technological) singularity.
I think we've pushed this "anyone can grow up to be president" thing too far.
I'm betting that it will suck ass.
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"Outlook not so good." That magic 8-ball knows everything! I'll ask about Exchange Server next.
Building
Antennae
Span
Earth
Orbit
Why people keep posting that?
There are only 2 buttons: Lobby and Penthouse!
It doesn't mean much now, it's built for the future.
The hard part will be lifting the cable up in the first place.
Make it in space, and lower it to the planet surface.
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I'm a little confused what a space elevator would do for us? I mean, it's not like you're weightless when you get above the atmosphere, you have to be orbiting the earth for that effect. So you go up the the top of the elevator and then what? Take cool pictures to post on your web site?
I can't imagine they could build a building large enough to house much research in because it would have to be entirely supported be the elevator and if humans are to go up there it would require a lot of insulation and reinforcement to keep it pressurized.
I guess maybe we could build a small elevator to send up "space probes" to do automated research, but that seems like even more effort than launching them on a reusable rocket. And they wouldn't get very far on an elevator either.
Dammit, it's supposed to be a stairway to heaven, not a friggin elevator.
The attraction force between two bodies is given by F=G(m1*m2)/(d^2) (G=6,672*10^-11 N m^2/kg^2)- everything in SI of course.
The mass of earth is 5,977*10^25 kg and the mass of the elevator could be something like 1*10^4 kg. Reasonable estimate, maybe a bit on the short side - but they dont need to be that big.
Say things are lifted to 5*10^5 meters (you dont need to lift things to a 36 000 km orbit) you get..
F=G*(M[earth]*M[elevator])/(distance^2)
F=6.672*10^-11*5,977*10^25*1*10^4/(distance^2)
At ground level, the distance is 6000 km - giving F=1.1MN. At orbit (distance 6500km), the force is 9.4MN. The difference is just 15% - which can be easily taken care of by motors or even just by dropping parts of the counterweight/elevator as you go higher.
Or am i missing something obvious?
-henrik
An estimate has already been made that vs reusable launch vehicles, a space elevator may be able to achieve an advantage of 1000:1 or better in price per kilogram lifted into orbit. Possibly as much as 10K:1 advantage.
There are plenty of companies who lift kilograms into orbit to make this financially viable if the construction costs can be brought into the range where either a government or a very large aerospace firm can consider constructing one.
Scientific American had a very good discussion of the subject back in decemberish?
"Who is the Journal of Quantum Physics going to believe?" --Stephen Hawking
Yes, someone will invent a way to make nanotubes cheaply, but then we will have to wait another 20 years for the patent to wear off, hmm I wondering if Clark but patents into his 50 year estimate :)
Note: you'd also have to deal with higher orbits for the counter weight too, which would probably extend up atleast a few KM just a note.
Following the "thought experiment" given in the article, if the space elevator is cut from the earth base at the bottom, nothing would happen. The space base of the elevator is in geostationary orbit. It is then extended both toward the earth and away from it so that the center of gravity remains at the space base. It's extended this way until the shaft reaches the earth base. The earth base is likely to be quite tall to make the shaft as short as possible. The shaft, space base, and counterweight do not rely on the earth base for support. Want to get freaky? Build the elevator so that the shaft doesn't even touch the earth base.
So what happens when some terrorist blows part of it up or it crumbles because the maintenance guy slacked off? I don't know, let's ask the experts here...What happens to a geostationary satellite that's overly weighted away from the planet? (Assuming the shaft is the section that gets bombed/crumbles.)
-sk
...as an aside, could you build the counterweight so that it serves as a sheild and/or solar array for the space base and shaft sections?
Another thing to consider is the safety. If you build this thing, and it collapses, it could theoretically tear the earth in 2.
Just a few random thoughts.
I think the Saturnians tried this millions of years ago, and look what happend to them: planet pulled apart into a low density giant; stupid rings make space travel essentially impossible; civilization destroyed, etc. I say we wait for antigravity drive.
I don't think a non-tapering stalk is feasable. You want to taper, so that the minimum stress is on each portion. You start with the stress at the end points, and you need 1 unit to handle that stress. A bit further in, and you need 1 unit to handle the end point stress, and 1 unit to handle the stress of the stalk from the end to that point, and that means you need to taper. It's the same reason why we build our tallest buildings tapering, except in that instance the taper is away from the ground instead of to it.
O----x----o
O= earth
o= counterweight
x= construction satellite
The bit you might be missing is that you want to attach the counterweight and the earth at close to the same time, so that the beanstalk goes from being under tension at neither end, to under tension at both ends.
Arthur C Clarke's Space Odyssey 3001 - printed in 1997 - have space elevators and in the end of the book he explains that they could very well be possible to manufacture using tubular buckminsterfullerene. In the back of the book he says:
"Meanwhile, the discovery of the third form of carbon, buckminsterfullerene (C60) has made the concept of the Space Elevator much more plausible. In 1990 a group of chemists at Rice University, Houston, produced a tubular form of C60 - which has far greater tensile strength than diamond. The group's leader, Dr. Smalley, even went so far as to claim it was the strongest material that could ever exist - and added that it would make possible the construction of the Space Elevator."
"Terrorists attacking beanstalks" is a very common theme. I've seen several short stories directly address the attacks, and indirect references in Friday (Robert Heinlein; Lima stalk) and the David Brin "Startide Rising" universe (where one character's last view of his wife was her losing her grip at the 20 km level... but I think that was just a partial stalk.
In fact, I believe the first story involving beanstalks involve an attack on one - the companion "science fact" article explained their physics. I'm sure I'll remember the name of the author just after I hit submit - probably either Benford or Sheffeld.
For every complex problem there is an answer that is clear, simple, and wrong. -- H L Mencken
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Patrick Doyle
I mod down every jackass who puts his moderation policy in his sig. Oh, wait a sec....
Brazil?
Ecuador? You could anchor it in the Andes and save a few miles of cable.
So will spray-paint stick to that fancy carbon shit? Cuz we ain't gonna let Whitey forget they roots, nowahmsayn?
"Smear'd with gumms of glutenous heat, I touch..." - Comus, John Milton
The House Between - Original Sci-Fi Series
But a geostationary orbit means that it will stay over the same spot all the time. Where do these forces come from? Is it all the material in between that would naturally have faster orbits at their height?
BTW, it's probbaly better to ship up the parts of a sapce ship and assemble it there, rather than lifting the thing up there whole.
Agreed. Robinson's RGB Mars rule. One point of interest which I must raise as something of an SF buff, is Charles Sheffield's book The Web Between the Worlds. It's all (um, almost) about space elevator (or "beanstalk" as he prefers to call them) technology, some of its implications, with lots of technical background. And, you gotta love the part where Mr Sheffield "objects" to Robinson's crashing elevator, because it destroys the city where the elevator was anchored to Mars. The name of the city? Sheffield, of course. ;^)
main(O){10<putchar(4^--O?77-(15&5128 >>4*O):10)&&main(2+O);}
makes sure that the upper terminus can't have a circular orbit - it will have to slide on the cable like a bead on a string
In the Mars trilogy the 'stalk was cut away from its upper anchor and gravity took over ... as it starts to move closer to the planet it starts to spin up (moving to a lower orbit and all that) . with the bottom still attached the result is that it starts to wrap around the planet coming down faster and faster as more and more of it comes in
I don't want to be a party pooper, but I beleive it was on slashdot that I read about the space elevator, that would use a nanotube rope.
I even think Isac Asimov was mentioned as the author of a novel where such an elevator is mentioned. In this novel the elevator has it's earth base on Sri Lanka.
Or maybe it was some other sci-fi writer, but that was the idea.
Sigged!
I think I got a spam the other day advertising just that.
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It seems to me like there would be a problem in that you still need to impart that 17k mph orbital speed to whatever you lift up. Since the elevator car just lifts straight up, the acceleration would come out of the inertia of the elevator itself, which would slow it down over time, causing it to smack into the earth at hypersonic speeds, destroying civilization as we know it.
(before you question the physics, do this: put on your socks, go in the kitchen, spin around with your arms out. bring them in. watch self speed up. extend. watch self slow down)
Am I missing anything? Do current plans just call for having a rocket on the station to keep it at the right velocity? How would it work with lateral forces on the cable itself?
The perfect carbon source and counterweight would be a carbonaceous asteroid. We snag one, put it in geosynchronous orbit, and weave the cable downward from it. We pull in additional asteroids from time to time and use solar energy to convert those asteroids' mass into plasma for thrust to keep the anchor asteroid stable. We lower the cable through the atmosphere, and meet it with a several mile high anchor structure/building.
Sounds simple enough, but I suspect to weave the cable we need to wait for nanotech assemblers, and of course we also have to get out to the asteroid belt and actually do something with them other than bump our probes into them. :)
The other nice feature here would be the solar farm required for the plasma generation station could later be used to send power down the cable to the large city which would undoubtedly develop around the cable's base.
Get off my virtual lawn, you damned virtual kids!
The real problem is all the orbiting nuts & bolts that will strike the elavator at 17,000 mph.
If the construction of the ISS is by all means a small project compared to this one and it's alreday over budget and delayed. Imagine what it would take to coordinate the creation of technology to produce those high amounts of new materials. This would be an endeavour that will dwarf the manhatan project and puting a man on the moon altogether. If we can't put a crew on Mars 32 years after setting foot on the Moon there is a very slim possibility of pulling this one out.
"In God we trust, all others must bring data" - W. Edwards Deming
For anyone who has any interest whatsoever in engineering, I highly suggest the book Cat's Paws and Catapults. It details the physics involved in much of these "engineering enigmas."
...Anyway, a counterweight would be useless because of the gravitational force, but then you have to realize that it would be absolutely impossible to use a counterweight in the first place. Even if you could make a cable out of carbon nanotubes, by attaching a cable from the Earth to a space station in the sky, you suddenly render the entire space station to the gravitational pull on the rope.
Just like flying a kite...when you make a kite, you don't use steel cable, because there's no way the wind force on the kite can support the weight of the steel cable. Because there is a gravitational pull on the cable, anything attached to the cable is going to be pulled with it.
Now, let's say you take a different approach: turn the "tube" from the Earth to the space station into a vacuum tube. That way you could set up some mag-lev propulsion system to go back and forth between points A and B. But then you run into two more major problems.
1) Spacial disturbances. There is turbulence in space...solar winds, debris orbiting the Earth, the gravitational pull of the sun with different pulls on Earth and its "attached space station," and plenty others, which would put an incredible amount of sheer and stress on anything running between the Earth and the Station that it would break. That would not be a fun ride for whoever's going between point A and point B (either you'll be jetisoned out into the outer atmospheres of Earth and enjoy burning up on your way back in, or you'll enjoy being propelled down to the Earth from three or more miles up).
2) You'd cause the space station to fall back to Earth. The ISS revolves around the Earth once every ninty minutes. Why? Because that velocity maintains their orbit. A balance of inertia and free-fall causes the ISS to "orbit" Earth. By slowing down its speed, you slow down inertia, therefore destroying the balance, causing the ISS to "free-fall" back down to Earth, aka give everyone down below a multi-billion dollar fireworks show.
Heck, with all the money they're spending on this program, I would think that they stand a better chance investing in learning how to beam people between point A and point B rather than trying to build some carnival ride into space.
Well, um... great concept, but I think you're ignoring the fact that most of the good humor on Slashdot depends on the context of the discussion. I don't really think most of the +5 funny posts would stand on thier own.
"The new wave is not value-added; it's garbage-subtracted" - Esther Dyson, Dec 1994
Excuse me if I am full of shit but I think the problem with your solution is that the added tension of the weight of the cable in your solution would mean that an incredibly efficient system would need to be used for joining, and I do not believe there is a current technology to do this. In summary the tensile strength requirement includes the requirement to carry the weight of the cable itself and once you adjust the weight of the cable you need more strength. If you can do it....choose your equatorial home with the ability to raise the budget!
Never underestimate the dark side of the Source
You also have to work your way through a fucking retarded matriarchal society at the beginning of (or all the way through?) Green Mars, which I never got past.
The only "intuitive" interface is the nipple. After that, it's all learned.
"The question of whether a computer can think is no more interesting than that of whether a submarine can swim" -EWD
The major stumbling block with building a space elevator has nothing to do with whether it is theoretically possible to build one, but rather with economics.
Let us assume, for the purposes of illustration, that all this technology was totally proven and risk-free. We have carbon tube launch vehicles and a potential carbon tube elevator. I will blithely also make up a few more numbers: Counting sustaining costs, an ultra-light ultra-strong space elevator trip costs only 1/4 that of a new ultra-light ultra-strong space vehicle, and it takes a mere 100,000 flights to build the elevator.
My assumptions are probably wildly optimistic, but the conclusion you reach still shows why it won't be done: You break even when you reach (merely) your 125,000th trip into space.
Even the most wide eyed space enthusiast would have trouble justifying such demand for space travel.
Therefore, I propose we find the amount of mass and distance needed to perform the same thing with the earth. Thousands of platforms/elevators that will slow the earths rotation giving us more bag/sex time... then on special holidays like MartiGras, we quickly retract these and speed up the Earths rotation.... WEEEEEEEEEEE!!!
All in jest, any morons pointing out actual mathmatical formula that proves this or that isn't possible, please go and get laid... quickly!
I seek not only to follow in the footsteps of the men of old, I seek the things they sought.
In Nick Park's claymation Wallace and Gromit episode entitled "A Grand Day Out", inventor Wallace creates a rocket to go to the moon, because they need cheese, and as everyone knows, that's what the moon is made of. The dumber people think you are, the more surprised they'll be when you kill them
Unfortunately, you have simplified the problem too much in the heat of your arrogance. While pressure can be regulated on craft such as airplanes or submarines, this is because you are dealing with a closed vessel of limited size. A space elevator, if ever built, would have incredible length and girth to accomodate more than people. At it's smallest, the tube would require an incredible amount of effort to keep pressurized. In addition, the compressors would most likely need to be placed along the length of the tube. However, the tube does not necessarily need to be pressurized. If the car of the elevator were to be properly equipped, you would not have to. Yet this means that the elevator would have to carry an oxygen source.
Since you thought of the problem as merely something tethered in orbit, it's obvious you oversimplified things. The problem is not one that is easy nor feasible. You err in thinking that pressurization would be easy. The entire project would be trememndously difficult and, despite the optimistic tone of the article, not possible at this time in our technological development. Also, as had been said in the article, the elevator will not provide a tremendous benefit to the holding nation. The reason is as follows: explosive weapons. This structure would be extremely vulnerable along the whole of its incredible length.
Pax Digitalia
I presented multiple possibilities on ways of accomplishing the idea. I said there were two situations: one where you pressurize the interior and one where you pressurize the car. While the concept with the cart running internal requires a lot more to accomplish, it has actually been one suggested by some.
As for your assertion of my stupidity, I would remind you that since the entire concept is just that, a concept, there is no standard to compare against.
Finally, to argue semantics you should have learned in 5th grade geometry: a tube is a cylinder with another cylinder with the same height yet smaller radius subtracted from the original. To argue that a tube has nothing within a tube to pressurize is to ignore everything you should have learned in school.
Pax Digitalia
However, you said tube. You didn't say nanotube. Without the prefix one assumes that a fool like you is using the word incorrectly to refer to the concept I spoke of: an internal lift. Perhaps you should remember to be precise in your language if you'd like to be arrogant. No one is debating the size of a nanotube. No one ever intended to. It is only by your diminished ability to read that you came to this conclusion.
If you intend to speak of the cable, say cable. Do not call it a tube. If you intend to speak of the nanotubes, say nanotubes not tubes. If you wish to speak about the internal concept of space elevators, say tube all you want. You are in the wrong.
Pax Digitalia
In case you haven't realized by my ignoring your previous, extraordinarily similar response, I'm sick of trying to explain to you that I covered both ideas. Instead, you feel the need to repeat yourself by responding to the original post not once, but twice, with the same trite crap you've said before. I never said that the only concept proposed for a space elevator was one using a core cable. I also never said the only one was one using an internal car. However, you are mistaken in assuming that the pseudoscientists of scifi, whom you seem to think speak gospel, have never proposed both models.
Also, before you speak about using bloated, pompous language, perhaps you should make sure that you don't misuse the bloated, pompous words that you use yourself in an attempt to sound intelligent. If you wish to take issue with my use of the English language, perhaps you should first grasp the basic concepts.
It's obvious that you have no indepth knowledge of carbon nanotech otherwise you wouldn't be so ludicrously lauding the material. You can not create a cable that could withstand an attack with even todays martial technology, and also incorporate the mag track you would need for the propulsion. The article conveniently ignores this fact. If you, being well versed in the crap SciFi authors come up with, know what the current "paradigm" uses to circumvent this, I'd be glad to hear.
I'll admit, that the internalized elevator is incredibly demented. However, the work that this idea comes from is quite old. While you may fancy yourself quite the scifi reader, you must not read some of the odd writings of old.
I was merely speaking of all the different proposals, particularly the one I assumed the root author, in his odd statement, was referring to. The fact that you seem to think that I proposed this merely to be contrary angers me. If I assumed wrong, and he wasn't speaking about an internal model, then I'm puzzled as to how there would be pressure problems.
Pax Digitalia
The cord should have some sort of self-destruct feature. The real threat is the top of the cord -- it's more massive, higher in the gravity well, and is constantly pulled planetward by cord below it. By cutting the cord, you ensure the top will strike later and more softly. The bottom, of course, will strike sooner and harder, but that's an easy trade-off. Cutting into many pieces would also spread out the impact time, turning a single cataclysm into a sustained round of heavy abuse. And since the cuts would be planned, most of the falling objects will have a predetermined size and mass, and a somewhat predictable impact profile. With good enough simulation, much of the cord might be cut into pieces such that they fall in "safe" areas.
The top would probably still be bad news, though. I think the best strategy would be to cut off the biggest possible piece from the top and tow it back into orbit, and chop the bottom into the smallest practical pieces and get away from the impact path.
A lunar elevator might well be tougher to build than a terrestrial one (I'd have to see the math to be sure). The length of the elevator depends on the speed of rotation of the body it's being built on as well as its mass- it needs to extend through the synchronous point- so the fact that the moon's rotational period is almost 30 times longer than the Earth's would mean it would be tougher than you think. Putting one on Venus would be impossible because its rotational period is so long. In that sense, it would have been a lot easier to build one on Earth a few hundred million years ago when the rotational period was shorter and the geosynchronous point was lower.
There's no point in questioning authority if you aren't going to listen to the answers.
The amount of destruction is going to be strongly dependent on where the break happens and the exact design of the elevator. The one in Red Mars was essentially a worst-case scenario: a comparatively thick, non-tapered elevator (which would be possible on Mars), a thin atmosphere that didn't provide much protection against falling objects, and a break at the ballast asteroid that produced the maximum possible material to fall. In such a case you would have a particularly nasty fall. FWIW, the sabotage in that case was the deliberate separation of the ballast asteroid by destroying its achoring to the cable, rather than an attempt to break the strand itself- not something that would be defended against by anti-breakage measures.
I also think that your suggestion of designed in breakage system to chop off chunks as it fell would be a truly bad one. Adding in such a system would actually make the elevator more dangerous, as it could cause an undesired cable breakage if it were accidentally or deliberately set off when it shouldn't be. A really dastardly terrorist could crack the control system, blow up the highest mounted cable-breaking charge to precipitate a fall, and then crash the rest of the system. Then you have a falling cable and no way to stop it- the exact thing that you're trying to prevent. IMO Robinson's proposed alternative- built in anti-debris defense stations along the cable- is a more plausible solution to the problem.
There's no point in questioning authority if you aren't going to listen to the answers.
I think the damage caused by a space elevator falling on Earth would be considerably more than that portrayed in Red Mars. Firstly our gravity well is stronger, secondly, the elevator cable would fall mostly into the ocean, which would cause massive waves, probably wreck a lot of coastal cities.
"Mind, as manifested by the capacity to make choices, is to some extent present in every electron." -Freeman Dyson
if i did the math right we only have to wait 50 years for the 47000km tubes to be avalable
Ascii artist &
Wouldn't this thing need to be flexible though? If it's too rigid, it'll snap. I can't imagine even a diamond being strong enough to keep a structure of that size rigid. If it can't bend, it'll break. I think that would qualify as a Bad Thing®.
--
I have seen mention of the physics, the construction, the economics, and someone mentioned social issues.
These seem to be the ones always discussed.
How about the meteorological effects this will have?
How about the ecological effects?
how about just a measly Sky Scraper first? If you can build a 47000km elevator I suspect you could make one heck of an office building.
lol, the white man made war right? after the south amarican people and the Africans stop killing one another and enter the world market on the level of the EU and US THEN we can talk, untill then, keep killing one another.
Did i just feed a troll?
________
Does anyone actually have a Java program designed to control air traffic, or for the operation of a nuclear facility?
No, we just need to make 4mm nanotubes and weave them together into a 47,000km cable. Nanotubes are currently in micro-meter lengths; 4 millimeter nanotubes will be cohesive enough to provide a strong weave.
Can we get a "-1 Wrong" moderation option?
The hard part will be lifting the cable up in the first place. That's the only problem I haven't heard solved yet.
Can we get a "-1 Wrong" moderation option?
No elevator cable, use magnetics instead. Electromagnets evenly spaced along the way just have to lift the elevator a few inches.
Can we get a "-1 Wrong" moderation option?
Gee, they've solved THAT problem with airplanes and rockets, right? Airtight pressurized cabins? ever heard of those?
Can we get a "-1 Wrong" moderation option?
this isn't another one of those penis extension spam email things i keep getting, is it?
we just shift from a WAR ON DRUGS to a WAR ON SPACE.
... in less than a decade, we have one in the Carribean....
A few shinny suits from a good PR house could have it wrapped up in no time
-- www.globaltics.net
Political discussion for a new world
... a space elevator, they could get those parts up in no time...
-- www.globaltics.net
Political discussion for a new world
Do you have any idea how much carbon that would remove from out biosphere!? The surface temperatures of the Earth would drop, growing the ice-caps and lowering the sea level! Catastrophic changes of weather patterns could occur!
We need an international treaty (which trumps all such petty issues as "national sovereignty" that might get in the way). To prevent this from happening!
Failing that, we should ramp up a massive effort to extract more carbon from the ground and introduce it into our biosphere by burning fossil fuels. Everybody leave your cars running all day, every day, for the rest of the Century... that might almost be enough to give us a chance. If you drive a small car, or an electric, go out and get the biggest-assed SUV you can afford. Hurry, your planet needs you.
Information wants to be anthropomorphized.
I felt that the first book in the series, Red Mars, had more fruitful discussion of the role of space elevators in a changing economic system.
This page is a worthwhile discussion page on the issues raised in Red Mars, for those interested.
Devolver's Homepage... more fun than a box of crackerjacks.
Centrifugal force will keep the elevator up. Placing a large weight (say, an asteroid) at the top of the cable will keep it in place, then the speed of the earth rotating will create a centrifugal effect, keeping the rock up and thus keeping the cable up.
Devolver's Homepage... more fun than a box of crackerjacks.
You've actually hit upon a lot of the ideas in the book; you should probably try reading it, if it sounds at all interesting, you would probably enjoy it.
To clarify what happens in the book: The terrorists blow up the central portion of the space elevator, pretty much directly at the midpoint. The top half flies harmlessly into space. The bottom half, now no longer balanced by the top half, flies into the ground.
And since it's made of these insanely strong carbon tubes, it doesn't crumble or break. It's a giant tube, thousands of kilometers long, falling into the earth. (If this still doesn't sound bad, here's the right thought experiment. Imagine cutting down a tree (and arguably a tree isn't such a bad model for carbon tubules). If you've ever cut down a big tree, you know the amount of force with which it hits the earth. Now imagine that same tree, except now it extends 20Km into the sky.
For the people who are still nay-sayers: Try computing the potential energy stored within a 5kg mass 10,000 km above the earth. Now convert that to kinetic energy and figure out the ground velocity. (Given, energy will be burnt up or diminished in the atmosphere, but anything that hits will have lotsnlots of joules.) Larry Niven talks about dropping 'crowbars' (with minimal guidance/targeting) from orbit as a weapon in the book Footfall. It's actually amazing how much power such a weapon could hold. (A projective travelling at 3000 m/s has a much kinetic energy equal to its weight in high explosives.)
In the Red Mars, Green Mars, Blue Mars trilogy by Kim Stanley Robinson, he describes a space elevator on Mars which is destroyed by terrorists. The effects of the billions of tons of carbon tubules smashing into Mars as the space elevator falls (wrapping itself around Mars in the process) is on a par with the destruction caused by asteroid/comet impact.
The books are quite good, with a lot of cool ideas, and are probably one of the most realistic treatments of how we could terraform Mars. But you'll have to work your way through some lengthy discussions about the geology of the red planet.
sure, everyone around the equator is kinda disappointed, but what a show!
why not embed small nuclear (or since we are daydreaming, antimatter) charges to blow it up into tiny pieces if it starts to fall.
and what about the jackass who pushes all the buttons just before he gets off?
/m
Why do you use a sig from a Nazi war criminal?
He caused the death of thousands of slave laborers.
Seems to me that the description in the article can't be quite complete:
imagine elongating the satellite inwards towards the Earth, and at the same time outwards into space, so that its centre of mass remains in geostationary orbit.
This might be fine for a quick and dirty thought experiment (so it's fine for this article), but it's obvious that the centre of mass is an approximation for spherical objects, and it won't hold up if you deform it too much, which of course, is exactly what we're doing.
I don't know enough physics to figure this out myself... Anyone have a more complete description of the mechanics, or a link to some website? How exactly do you place the counterweight?
--
Accountability on the heads of the powerful.
Power in the hands of the accountable.
Bringing it back to the airplane/space shuttle example. In any case, in most plans, the car runs up and down the outside of the shaft, rather than inside. That saves a great deal of material, and pretty much mandates the pressurized section being restricted to the car.
___
__
Do ya feel happy-go-lucky, punk?
...the price of land near the equator will increase shortly. :)
I hadn't known there were so many idiots in the world until I started using the Internet -Stanislaw Lem
Three words: linear magnetic motors. You don't have to take the description "elevator" so litterally.
I hadn't known there were so many idiots in the world until I started using the Internet -Stanislaw Lem
However, there is a huge problem with a space elevator: The Van Allen belt. By its nature, a space elevator would have to cut right through it... and it's something like 2500 rems of radiation.
I hadn't known there were so many idiots in the world until I started using the Internet -Stanislaw Lem
You're missing the centrifugal force. But that's moot anyway.
I hadn't known there were so many idiots in the world until I started using the Internet -Stanislaw Lem
The Van Allen belt isn't continuous - there are holes, mainly towards the poles. That's the trajectory that manned spacecraft adopt, BTW. But at the equator, it's continuous.
I hadn't known there were so many idiots in the world until I started using the Internet -Stanislaw Lem
Uh, no. The belt itself is a region where charged particles from the solar wind are concentrated by earth's magnetic field, and this is beneficial, because it shields us down here from the said solar wind. But once you clear the belt (BTW, there is more than one belt, so we hould really call them "belts"), you get exposed to the background radiation which is certainly higher than on earth's surface, but not unacceptably high or something that can't be shielded.
I hadn't known there were so many idiots in the world until I started using the Internet -Stanislaw Lem
Huh? If you think a 6-foot-thick lead wall would be cost-effective on such a device, think again...
It may work for nuclear reactors, but this doesn't make it a solution for the space elevator.
I hadn't known there were so many idiots in the world until I started using the Internet -Stanislaw Lem
"Andromeda Strain" - one of the early books by Michael Crichton (of "Jurassic Park" fame).
I hadn't known there were so many idiots in the world until I started using the Internet -Stanislaw Lem
And regulators...
You know, those things that regulate...
What makes you think that pressure in an airplane or space shuttle that is autonomous is easier that regulating pressure in something that is tethered to the earth?
This is in fact an easier feat than attempting to regulate pressure for a human to travel to the bottom of say the marianas trench for instance.
I do not get it: To 'elevate' something into space you have to 'hook' the upper part of the elevator to a space station. Then it can use some kind of a motor to pull the cargo. As space station pulls the cargo it goes down itself. For this whole thing to work you would need to use rocket engine to keep the station's orbit. To use rocket engine you need fuel. So what is the difference if you still need to get the fuel and the cargo into the orbit from the level 0? dba.
...to nowhere!
where is this "elevator" going to lead to?
better yet, it's a long trip, what are you gonna do on the way? i hope there is going to be a mcdonalds or something on the way, i reckon people would get hungry!
and what about funding? i mean this is gonna cost a heap! who is going to pay for it? well there could be a few billboards on the way, advertising could rake in a fair bit of cash.
Kids, you tried your best and you failed miserably. The lesson is, never try. -- Homer J. Simpson
Hemos posted on this same topic just a few months ago...guess he forgot ;)
They even used the same (rather silly) concept art.
Xentax
You shouldn't verb words.
Arthur C Clarke's Space Odyssey 3001 - printed in 1997 - have space elevators and in the end of the book he explains that they could very well be possible to manufacture using tubular buckminsterfullerene.
Fool! It may have been printed in 1997, but it was WRITTEN in 3001!
"And like that
Can you imagine a world where near-earth-orbit travel becomes almost banal?
The least popular Jackson brother may have wasted that 20 million after all.
There was actually a proposal (to one of the gov agencies) back in the late 70's to generate power via these tall structures. The proposal outlined the basic science involved, and pointed out that technology was available to build such a structure, at a cost not too different from nuclear plants being proposed at the time.
Not transparent, just by condensing water at the top. The resulting internal downdraft would drive turbines at the base.
kinda.
I am not sure about the statement another poster made about kevlar being able to stretch to 300%...
but I was watching a show on spider silk vs. kevlar, and the reason that it is "stronger" is because it stretches more than kevlar does before breaking. as I recall it was near double the percentage of kevlar.
The article kept on mentioning that the cable would have to be hooked up to a satellite on a geostationary orbit. Correct me if my physics aren't right, but wouldn't the structure of the string itself be enough to keep it straight? By analogy you can swing a string round keeping it straight even when it does not have a weight at the end of it. This possibility appears to be a function of the rigidity of string.
People also tend to forget that crystalline carbon would also satisfy the requiresments for a "space elevator". Crystalline carbon, better known as diamond, has sufficient strength to hand all the way down from GeoSync Orbit. I would think that it might be easier to develop a way to mass synthesize diamond (not jewelary grade, trolls) and use it to build this thing, rather than grow 46,000K long tubes.
The one in the lowest orbit is just long enough to dip down into the atmosphere, where you "dock" with it using some type of plane, etc. THen the end keeps swinging up and tosses the cargo into orbit like a giant sling (a kilometers long sling). You also put one in orbit around the Moon. Easy travel back and forth. Look it up.
"I'm about to drop the hammer and dispense some indiscriminate justice!"
And when a multibillion-dollar project is at stake, what engineer would work on the ragged edge?
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A person of moderate zeal
At least what will make it work in my lifetime?
Given that the article talked about it happening by the end of the century, probably nothing.
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A person of moderate zeal
The two articles have the same artist rendition at the top, and drops the same numbers, but the September article has more cool pictures.
--brian
When (not if anymore :o) such an elevator is build, the first will probably be a joint-venture between a number of country's, like what's happening with the ISS. A single nation wouldn't be able to do it all by itself, the costs are way to high, and the monopoly-position would alert anyone with a grain of common-sence. Maybe the UN should start it all up in 50 years, but all you american's first need to pay those UN-bill's before we can start with Eiffel#2 :o)
This sig is intentionally left blank
In Kim Stanley Robinsons {Red|Green|Blue} Mars series (mentioned earlier in this thread) one of the problems of building a space elevator on Mars is the fact that one of the moons orbits below geosynch orbit. They solve it by vibrating the entire elevator so the moon misses every time.
Doing this with multiple objects could be interesting...
This is the most comprehensive site I've found for deep bakground on Carbon Nanotubes: http://www.pa.msu.edu/cmp/csc/nanotube.html
--CTH
--
--Got Lists? | Top 95 Star Wars Line
Well, I got halfway through the other comments, and haven't seen a thread bringing up this point yet, so...
Has anyone given any thought to how a stationary permanent space elevator will restrict the number of orbits available? No more equatorial orbits at all, at any height (except geosynch), and any orbits that cross the equator (say, the polar orbits that many spy satellites are on) would have to be VERY carefully calculated so that they would be in a resonance pattern with the elevator, and miss it every time. Well, that covers every orbit possible, doesn't it.
Other people's thoughts on this?
PS - credit to Larry Niven Rainbow Mars for bringing up that objection.
It may look like I'm doing nothing, but I'm actively waiting for my problems to go away.
--Scott Adams
Actually, you'd want to make it in the orbit it's going to stay in. "Lower" both ends in opposite directions as you build it. Red Mars says it nicely, move an asteroid in at the balance point.
The asteroid eventually becomes the ballast, after the elevator is complete.
Eww Good Idea, we only need a couple million more goats and we can get into space! GOATS are for the future, for space!
Seriously though, do you think we could make a space elevator out of a fiber that stretches 300% of its own length?
----- 70% of all statistics are completely made up.
Concerning the falling elevator scenario - dense air will make things different on the Earth, at least higher parts will have no chances to reach ground, but, nevertheless, it would be tremendous catastrophe.
Crio
Even if they can get these tubes to grow to 47,000km, what is going to lift the people up? I mean, think about it, 47,000km is a long distance for an elevator. Cables aren't going to cut it, and if your lucky, your might be able to do it with magnets. But really, what is going to make this work? At least what will make it work in my lifetime?
01101001 01100001 01101101 01101110 01101111 01110100 01100001 01101100 01100001 01110111 01111001 01100101 01110010
1st of all let me say my physics are, eehm, rather corroded. Nonetheless, perhaps someone can answer me this question: If you build a construction of this magnitude, won't that change the aerodynamics (or whatever they're called in space) of planet Earth, which allow it to remain stable in it's own orbit, around the sun, in the first place?
regards, EK
--
Gosh, thanks. That must be why the other ships call me Meatfucker -- GCU Grey Area (Eccentric)
do you really know how many tons of CO2 you would need? also, the 2 O atoms would be split off. Their isn't enough C in the air to do that. Their is enough captured in the ground to do it, however. We may need to mine the moon to do it, if we don't want to do mass conversion of Coal to Carbon.
:)
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Provide high speed connections to your ISP with out the expensive infrastructure!
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Hey, at least I didn't use the BLINK tag!
If the elevator is severed from its counterweight it will accelerate as it falls. Take a bullwhip, hold it by the handle, and spin in a circle so that the tip is "orbiting" you. Suddenly stop spinning. Let us know how tightly the whip wraps around you (analogy of impact of the cable) and whether the tip hurts when it hits you.
Brackets contain world's first nanosig, highly magnified:[.]
Being in the process of reading Kim Stanley Robinson's MARS trilogy, I found his solution rather interesting. First off, get yourself a nice carbonaceous asteroid. Park it in a Clark orbit over the equator. Then sic auotmation on it that eats the asteroid from the inside out and weaves the nanotube structure from it. Let the structure dangle above the surface of the Earth. Use station-keeping rockets to keep your hollowed out asteroid in place.
He convinces me that it can be done. :-)
The bitter lessons of a veteran coder: http://bitterprogrammer.blogspot.com
Oh, cool! We're almost there. So, when does it go up...next week, or do we have to wait until after the summer? By the way, just how much pure carbon do you think they'll need, anyhow? I might be able to spare a few grams of it from off the valves in my car...
For your security, this post has been encrypted with ROT-13, twice.
Some people here are concerned with what will happen if the structure will collapse. Well, it's not even a structure. If you read the article, you'll know it's a cable. Possibly a few feet thick. Not "billions of tons of carbon tubules". Granted, it would be one long cable, but the result of it falling would probably end up destroying the cable due to the variations in gravity and disrrupting it's pseudo-orbit, than destroying the Earth.
People have always been alarmists, I for one think this will be a great idea. You could send over a pound of stuff up to space for little over a dollar, compared to the thousands it costs now.
Frankly, we haven't even seen the start of the space age.
"I'll just chip in a bit for RedHat: I actually have that installed on my university machine." - Linus, '95
to would control it.
Though I find it very had to believe that the powers that be would allow some country outside the G8 to control a space elevator. Friggin Ron Reagan has a shitfit that Nicarauga has a democratically elected government that did not cow-tow to the Capitalistic line, what would his spiritual descendants do if say Libya built a space elevator?
If we had the technology to build tall structures several miles high, we could conceivably use it to generate electricity. The air in a tall transparent tube, maybe several meters across, should rise up very fast as it is heated by the sun. By installing high-yield wind turbine generators at regular locations inside the tube, it should be possible to generate enough electricity to make it economically attractive.
Questions to greenhouse physicists and structural engineers: What is wrong with the above scenario? Will it work? How much power can one generate from say, a mile-high glass structure that is about 10 meters across? How much would it cost?
Thanks for the links and the info. Very interesting. I wonder if there has been any sudies done on the ecological impact of the large-scale use of these chimneys.
What about transporters? Isn't anyone working on those? I saw them in Tron and all the Star Trek movies, someone's got to have some good ideas...
Really, keeping the elevator correctly pressurized has got to be a headache. After a few thousand feet we're going to have a whole bunch of dead people being elevated.
Perhaps they can play Stairway to Heaven...
Dancin Santa
one more reason to move as soon as i am done with highshcool...
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so i says to mable, i says
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so i says to mable, i says
It seems to me that an enzyme set would be ideally suited to building N-length nanotubes. Additionally, you could glue them together with that indestructable stuff barnacles use to cling to stuff. It's got huge compression strengths, while nanotubes have awesome tensional strength. Bio-composites anyone?
No, the elevator would be stationary with regard to the earth's surface, not necessarily the magnetic field. And as you can see here, there is a huge difference in the shape of the magnetic field with regard to where the sun is. Thus every day you'd be going through huge variations in magnetic field strength. And if nothing else, fluctuations in the field would also have unpredictable effects, and likely cause all manner of stress and strain. This is another good FAQ.
cryptochrome---If you can't trust a nerd, who can you trust?
Actually, nanotubes are NOT cohesive enough. In fact in nanotube composite materials, the tubes are so smooth and so non interactive that they slip around each other and any binding matrix. So I'm afraid we'll be needing that nanotube polymerase or polymerizing reaction or nanomachine constructor. Potentially some slight modifications may need to be made - if it's twice as strong as it needs to be, maybe we could compromise that strength a little by cross-linking them. If they were somewhat longer, weaving might also be an option. Perhaps carbon nanofibers (VGCF) would be easier to produce. How would they perform?
But there are other problems too. Nanotubes will degrade under certain high-energy conditions. Therefore they might not work so well in space. And finally, one of the forms of nanotubes is conducting. If you have an electrical conductor (the elevator wire) sweeping through a magnetic field (the earth's) you'll generate an electrical current in the conductor (high voltage, potentially useful) as well as mechanical force perpendicular to the magnetic field and the conductor (BIG problem). It wouldn't take long for that to be dragged down to earth. I'm not sure how the semiconductor form would hold up. Carbon nanofibers are very conductive too.
cryptochrome
---If you can't trust a nerd, who can you trust?
Uhh, how is the discussion of artificial spider silk, one of the Holy Grails of science, "Off topic"?
Over half the article talks about the problem of finding something strong enough, and pontificates about carbon nanotubes.
I am for the complete Trantorization of Earth.
> Friggin Ron Reagan has a shitfit that Nicarauga
> has a democratically elected government that did
> not cow-tow to the Capitalistic line,
That's because democracy is subordinate to freedom, not primary over it. You do not, in fact, have the right to vote away massive amounts of other people's freedom.
I say this space elevator is very important! Mr. President, we cannot allow the Rooskies to develop a space shaft before us. They'll heft nukyooler weapons and dangle them over Iowa. Mr. President, we must not allow a space shaft gap!
I am for the complete Trantorization of Earth.
Maglev still needs something to mag against, so you might as well attach a track of some sort to physically claw your way up. You'd probably end up with much less weight using a physical track than whatever maglev would require.
I am for the complete Trantorization of Earth.
Ehh, I just looked it up. One web site claimed spider silk was only 80% as strong tensile as Kevlar, so it isn't even as good.
I am for the complete Trantorization of Earth.
Some guy has a whole herd of breeding goats that have spider silk generators in their DNA, they extract the chemicals from goat milk, and presto! He's gearing up for commercial production.
That's way stronger than Kevlar, isn't it?
I am for the complete Trantorization of Earth.
...would cause the end of it to fly off into space with the remaining tether if a terrorist explosion separated the tether at some point. I don't think it would crash into the earh à la Red Mars...
You know, I was thinking about all the +4 and +5 Funnies that routinely pop up on Slashdot, and I suddenly came up with a great idea.
You see, not any one Slashdotter is routinely side-splitting, but all of us put together (with appropriate moderation) routinely come up with the finest tech humor around! So why not capitalize on it? Our timely, hilarious comments are like an open-source scripting (pardon the pun) of a late night comedian's monologue, a la Letterman!
Think of it! Every night Hemos or Taco gets on a live stream and goes through the day's news, complete with all the +5 punchlines and a live studio audience to laugh at them all over again. There can be celebrity guests too -- why not Slashdot regulars like Katz, or special guests like Mundie? Or how about the "Top Ten Trolls" of the day? We'll call it "Slashdot Tonight!"
It's time to tap the potential of this free, volunteer humor base! Who's with me?
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I wonder if you will have to give Gene Wilder a piece of chocolate before you can ride it.
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Is that all of you seem to be bassing your asserations about this crash off of a work of FICTION (Red Mars). Now I know that often SF authors do research and their secnarios are accurate, but this may not be the case. I'd consult a physics professor before making any firm judgement in this matter.
Are you saying you can't make a space elevator out of Lego ?
I think that the cocept is sound, my biggest concert however would be protecting this tower through the atmosphere. I mean, it would of course be subject to all of the storms and weather patters of whereever it was located. I would also hate to see the result of a plane colliding with such a structure
Do you really believe that this could ever be built by ONE country? Especially for the first one, the financial resources required would be enormous! It not like the only hurdles are scientific.
:)
And as far as the prospect of tearing the earth in two, just how well are you going to attach this thing
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Scientists restrict study to entire physical universe; creationist
- First, the lower parts of the elevator are very, very thin. If you just let them drop by themselves, they would be slowed to a relatively low speed by an atmosphere of any significant density. They don't have very far to fall in the first place.
- Second, the upper parts of the elevator are almost (geo/are)synchronous already. Cut them loose from the parts below and they stay in orbit; there is no "Earth-shattering kaboom!"
- The problem parts are the ones in the middle. If you have a mechanism to cut pieces off on command (and you'd have to, for damage management from space debris) you could just chop off chunks from the bottom as it dipped into the atmosphere; splitting them into narrow strands is good for extra points. Because the bottom end of the elevator-fragment is moving slowly, there is little energy in it and it can mostly be dissipated in the atmosphere.
- The falling of the elevator-fragment turns potential energy into kinetic energy, and chopping off the bottom end by degrees leaves most of that energy with the upper part. Eventually you've transferred enough energy to the remaining fragment that it has assumed an orbit. It's kind of useless as an elevator, but so long as you have raw materials floating around conveniently like that it would be not unreasonable to have a new elevator going in a very short time, built out of the salvaged pieces of the old one.
- You'd have to have this kind of failure-mode effects management built into the elevator anyway because a chunk of space rock could do what KSR's terrorists do. This renders the terrorist scenario just a little bit unbelievable in practice, regardless of how great a literary scene it makes.
In conclusion, I don't think that this is the kind of thing it makes sense to worry about even with today's technology, let alone the kind of damage-response mechanisms we will have developed by the time we get around to building things like this.--
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You might also want to look at this.
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On a discussion of ways to purify U-235 for making an atomic bomb (this was in the 1940's), a scientist was talking about atomic-mass spectrometers. He said, "A unit can purify uranium-235 more than sufficiently to make a bomb, but it would take a million years to purify enough for just one bomb."
Someone from the audience said, "So you build a million units, then it only takes one year."
We currently make cable in machines that go much more than one mile per hour. The rest is just assembly and orbital mechanics (you have to put the stuff in orbit and build it downward, or rather outward both ways from geosynchronous orbit).
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1. The aforementioned how to lift the cable.
2. Maintenance issues - what happens if the cable happens to break. Making and installing a new cable in the existing structure would probably be extraordinarily expensive. Seems like it would be time consuming at best to do any routine maintance on the elevator shaft.
3. How mad do you get at somebody whose kid presses all of the buttons on your way to the 213,117,876th floor?
4. As you get higher, the force of gravity will be less. Somehow you have to balance the g-forces of the speed of ascent with the steadily decreasing gravitational pull so that your passengers are neither squashed against the floor or floating around the ceiling.
5. You can't just use a cable to manipulate this car. When the car is at the top, there won't be enough gravity force to pull the car down (as conventional elevators have). You'll need to give it a push towards earth...then use the cable to keep the speed of the fall under control.
6. Nobody's ever constructed a structure inside the atmosphere at the kinds of altitudes we're talking about. There are all kinds of challeges to just existing at 40,000 feet much less trying to build a massive tower.
7. The stress on that structure at an altitude of 40,000 feet. As the earth spins, only the base of the tower is attached to earth, the rest of the tower has to withstand the torque that is applied by that.
Just some random thoughts. Some may have easy answers, some don't.
-Coach-
Perhaps the world's greatest tragedy is that ignorance is not impotence.
two parts: A. Dreams. A space elevator is imagined as an alternative to feul-based methods of reaching orbit. The complexities of the more likely designs require nothing less than new technology, invention of new materials; an elevator capable of acceleration, gravities, and life support - or basically a spaceship launched by cable. That's what we're really talking about here. A ship. We can build those. But, this cable/tower/counterweight/platform contrivance is presently an impossibility, theoretically or otherwise. Even if we could build it tomorrow, you're still moving "MASS." So? Well, now we're not just moving the mass of the aforementioned ship, now we have the mass of this elevator device included. No one knows just how massive it will really be, but there are no figures below millions of tons. Even a super monofilament cable would be massive at nearly 50 thousand feet, but that's not the worst of it. The orbital platform's mass must also be taken into the calculations. Its enough mass to equal dozens, perhaps hundreds of shuttle launches. All the transference of mass still requires energy. For this kind of energy, we're talking fusion or nuclear power. Its illegal to put nuclear power in space under international law, but that law might change. However, nuclear power might well be insufficient, given the extreme mass of a terrawatt nuclear plant! And fusion doesn't exist in a useable form yet. No, at the moment this is nothing but a crude dream. Maybe after Fusion becomes portable, and we invent superstrong filaments, and superconductors that operate at room temperature. Its simply "COST EFFECTIVE" to launch rockets, by comparison. I feel that the best look forward for now is the ground to orbit to ground shuttle design that doesn't require booster tanks. Fly into space the same way the SR72 and A2 did, and the Transonic Jet. If we could get the equivalent of a C17 cargo jet into low orbit just by flying it there, the elevator is unnecessary. B. Taking shots at Linux. I read articles critical of Linux as much as ones ripping MacroSloth. Remember how we used to bash MS because we hated having to use it, while Linux was still growing and couldn't run Mechwarrior? Now I see exactly the same grumbling from MS fronts about Linux. They hate having to use it, because their software can't. If GPL, or Linux, or open source was so bad it wouldn't be leading the industry now. I just applied for a new job, and the people there tell me 'you'll need to be fluent with Unix systems and C programming, we're phasing out the NT boxes.' This is no little company, but until I'm safely hired [or not] I'm not going to say who it is except that they are not MS. I never learned how to use NT. I hated it, and I still have 98 on one box. Now I can smile as I apply for positions that no longer ask me to learn it. PS. Slashdot still kicks butt. I haven't been to CNN's web pages in months, the best news is here.
we don't need no steenking signatures!
When I first started, it was a little painful, but I figured it had to be better than being painfully little. I was only hanging fishing weights from my wang, but I quickly increased the load (and needed higher chairs!).
Now I've had a special seat hung by thick steel cables between the Petronas Towers, from which I hang an oil tanker just inches from the ground. I'm doing it right now; I've got internet and everything up here. It feels wang-tastic.
It is a little-known fact that properly conditioned wang is the strongest material known to man, surpassing even carbon nanotubes.
Once day, I will be the first astronaut to double as a space elevator.
(this post is dedicated to Penny Arcade)
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Those silly spacedaily people, you don't need 1 continuous cable (assuming you don't use magnetics). Cable A lifts you 1 km, then cable B attaches (cable A is released) and pulls you another 1 km up, then cable C etc. 47,000 1 km cables powered by 47,000 motors. Actually, due to the decrease in gravity, the higher up you are the longer the cable can be.
Stick a metal pole parrel to the floor on a ball. Spin the ball, doesn't the pole fly off. Now stick a pole ontop of the ball, perpendicular to the floor and spin the ball. Wouldn't a polar space elevator require a lot less anchoring?
The whole cable thing bothers me... I just don't understand the concept of a tapered cable... In my mind it would have to be formed in a closed loop to keep the distribution of mass equal with a counterweight as in conventional elevators. But this thing tapers at the ends and has a huge bulge in the middle... how does that go around a pully? Even if that wasn't how it worked, how is the cable being driven? where is the end opposite the elevator car going? My thoughts revolve more around pneumatics as opposed to the linear induction motor. The mass of even aluminum along 36000km would be prohibitive, not to mention the power distribution. Why not simply apply a small amount of air pressure (and a huge volume of air) to the shaft to lift the elevator like the old pneumatic tubes? A pressure of 1psi across the area of a typical elevator (let's say 10'x10') would allow you to lift 14400lbs! (at sea level) I know people will envision air rushing out the open end of the tube, but I don't see this happening, as it doesn't happen in the wide-open atmosphere. The higher the car gets, the less pressure is required to lift it (not to mention gravity holding the air in the tube). Essentially it's just a pneumatic lift (like a hydraulic lift in low-rise buildings). There's probably a lot of holes in this I haven't thought of, and plenty of other solutions to the problem out there besides mine. But I think it's more workable than 47,000km long cables. Wow... that rambled on a bit.... NORgasmic
This kind of reminds me of Arthur C. Clarke's 3001. In the book there are 4 towers (one for each hemisphere) that stretch out beyond the upper reaches of the atmosphere. Virtually all astronomical observations and all shuttle/rocket launches take place from these towers for convenience. All in all it's a pretty cool idea. But I think he's right in that it's still a good ways away in the future.
This isn't correct. The cable can be under tension (a verifiable amount of force) from the counter weight beyond the geosync point. As long as the loads going up don't pull 'harder' than that tension, you don't need to worry about the whole shebang falling on your heads. And you don't *have* to use rocket fuel. In all likelyhood, the counterweight will probably be on some sort of motorized track system to adjust the tension as needed.
No! It's a *SIG*. Keep the Special Interest Groups away! (Con joke!)
actually that may not be that far fetched (as opposed with all this futuristic discussion...) ...
CNTs have very little defects , IIRC this is because they are a very steep energy local minima, or , put other words, once you have the start of an CNT, and heat it to 2000 degrees, it will reject other atoms for carbon in the right configuration (repair itself) (providing this is a single-walled NT, for multi-walled NTs the above/below layers limit this greatly)
so, I would guess heating an area of such a bundle to ~2000 K may even have a healing affect.
of course you need to take the large heat conductance into effect.
-- just a guess
Working for necessity's mother.
how much would you tip the bell hop?
being an elevator operator is usually a good job... but it has its ups and downs.
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Space elavator, huh? Saw those things on Star Trek a couple of times and thought they were the stupidest things in sci-fi. Who knew they were actually working on it. Can see the advangtages of it, though (for any country with enough money and balls to build it). Easier to lift cargo into space, heavier lift capacity. Also see potetntial disaster in it. As others have noted, if that thing were to come a tumblin' down, were toast. Gives me an idea, too. Take all the soot tossed into the atmosphere from coal and oil fired plants and process it into nanotubes. End up getting a lot out of this darn little idea: 1) Space uses (duh) 2) Clean up environment by cutting emisions 3) Solve energy crisis as new plants are built
-- If any of the above made sense, I assure it was purely by accident.
Another problem nobody ever mentions about the space tower is how long it takes to build. If it grows at one foot an hour it will take 13,000 years to reach geosychronous orbit. One foot a minute gets us down to 200 years. One mile an our is two and a half years. But how are you going to construct a tower that fast?
Can you imagine listening to elevator music for 47,000 kilometers???