Scientists gather to engineer space elevator

By
09.17.2003 :: 1:43PM EST

Space exploration has fired the imagination ever since Jules Verne penned From the Earth to the Moon and “Space, the final frontier…” was uttered on television. Images of humans whisking their way across the stars appeals to the romantic notion of exploring the unknown cosmos. But today we're rather hamstrung by our mother planet's stubborn gravity. Lifting material into orbit is fantastically expensive, on the order of US$10,000 per pound.

Costs like this have kept all but a few humans on the ground permanently, but there are a number of ideas floating around that could revolutionize space travel and bring costs down to the point where anyone could go into space. Chief among these ideas is the concept of a space elevator.

Right now, to get a pound of anything into orbit requires hundreds or even thousands of pounds of fuel, all exploding in a somewhat controlled, but extremely dangerous, fashion. Space elevators would do away with all of this. Instead of rockets, a cable would be suspended from a geosynchronous satellite down to a point on the Earth's surface near the equator. Anything destined for orbit would climb this cable more or less like a conventional elevator. No excessive G-forces, no exploding rockets, no massive aerodynamic stresses, just a smooth ascent to about 50 miles (83 km). Space elevators have been featured in science fiction for a while, but scientists recently gathered in Santa Fe, California to discuss how such a device could actually be built.

Oddly enough, we may already have the technology in place to do so. The biggest hurdle in constructing a space elevator is the cable itself. A geosynchronous satellite would orbit at an altitude of 64,800 miles (108,000 km). Even if made of the lightest, strongest metals known, a cable this long would snap under its own weight, to say nothing of transporting cargo.

Carbon nanotubes, however, have the requisite tensile strength, stiffness, and lightness to make such a cable. Experiments indicate the cable would be a hollow cylinder, as little as 3 feet (1 m) wide and as thin as a sheet of paper.

Formidable obstacles remain, however. Thus far no one has fabricated a carbon nanotube larger than microscopic size, although no one sees any reason why larger ones can't be made.

ERIC'S OPINION
I'll admit it: I'm a space exploration nut. I've followed everything there is to know about the Mercury, Gemini, Apollo, Soyuz, and other manned space programs. Hubble pictures grace my desktop. I'm a Star Trek afficionado. If it has anything to do with space and technology, I'm interested in it.

Space elevators, as I said above, will revolutionize the entire concept of space travel and might finally open up the stars for the largesse of humanity. It could be one of the best things that's every happened to this tiny blue orb.

NASA's commiting funds, but a paltry few million. NASA spends billions on such flawed programs as the Shuttle and the ISS. It's a pity NASA's vision no longer extends to the stars. It's instead rooted in lucrative government contracts and good ole boy networks. The spirit that fired Apollo is dead.

While writing this article, a darker thought intruded into this grandiose idea: terrorism. Building a space elevator would be incredibly expensive and time consuming. What a tempting target that would make for another plane filled with religious fanatics! Forget killing thousands of civilians by toppling skyscrapers, you could cripple a national space infrastructure quite easily by slicing the cable with an airliner, a fighter plane, or maybe even a small civilian aircraft.

Such a thing as a space elevator could enrich and enliven all of humanity, but I have no doubt that there's some wacko, some thug, or some fanatic out there right now who would cheerfully destroy it all out of sheer malice. Such is the reality of our world.

It is my sincere belief that opening space to cheaper exploration and exploitation will lead to a more stable, more prosperous global environment. Even our own solar system contains a virtually inexhaustible supply of resources and energy that's there for the taking. We need to get out there.

USER COMMENTS 81 comment(s)

And When The Cable Breaks(1:49pm EST Wed Sep 17 2003)if they can create such a cable, it comes crashing down killing thousands. – by The Shaft

Redundancy(2:07pm EST Wed Sep 17 2003)If you can make a single cable, you can make 3 or 4 spaced apart. So long as a single cable survives life is good.

It might also allow the maintenance/repair of an active elevator.

Space has always been a hostile environment, redundancy is always part of the equation.– by more is better

well…….(2:21pm EST Wed Sep 17 2003)I believe that we need some way to colinize other planets. I am also fascinated by space travel and exploration. But I don't think that suspending cables into space and creating an elavator is engineering or economically possible at this time in science. I'm sorry to say that this new idea does not create a fesible alternative of transportation to space. And I also concurr with Eric when he says it's a terrorists gift. Im afraid the only way we can reach the stars fornow is by rocketry. – by Alpha

Plus(2:22pm EST Wed Sep 17 2003)I am sure this would be heavily secured with rocket launchers and lasers and such – anything trying to get near would have it's ass blown off without second thought. I think one thing that 9/11 has shown all of us is that there are idiots in the world trying very hard to undermine thier children.. trust is earned and I don't think many people are willing to trust first anymore. Sad.. – by ai-joe

correction (2:23pm EST Wed Sep 17 2003)i misspelled colonize and didnt space between for and now – by alpha

Skeptical at best…(2:33pm EST Wed Sep 17 2003)Let's consider the required tensil strength required. The cable must be able to withstand the weight of the cable, the strength of the winds, thermal expansion/contraction plus the weight of any freight. This is all in addition to whatever exiting forces are on it due to the centrifical force that keeps the cable in place to start with.

So, say we can build it (which I think is a huge leap of faith). Consider the surface area exposed to the next huricane, thunderstorm or simple gust of wind. If it flexes, does the constant flexing set up a standing wave? How about elastic degradation? Oxidation? Lightning strikes? – by Hodar

wow, so much fear(2:38pm EST Wed Sep 17 2003)relax guys, stop watching fox news, something. the thing doesn't even exist, and already you are afraid of what it might do or what might happen to it.

it is far more likely that when an elevator is built, it will be coopted for military use, that is my fear.

but why focus on fears in the face of something with so much positiver potential. we can be aware of the dangers even as we are supporting this endevor, and hopefully we can see this in our lifetime. – by Stinky Pete

Isn't this(2:47pm EST Wed Sep 17 2003)an old Arthur Clarke story? The sequel to 2010? As I recall, the south Pacific, or Indian ocean are ideal locations. The human urge to explore can't be stopped, only delayed. – by Darwin

Worth to note…(2:50pm EST Wed Sep 17 2003)I think it's worth to note Arthur C. Clarke's novel “A Space Odyssey: 3001” in which he described huge towers dubbed “space elevators”. Also, in a later press conference about said book reporters asked him when he thought these space elevators would be developed. To which he replied, “Probably about 50 years after everyone quits laughing.”

Looks like we've stopped laughing because NASA (among others) has been researching this idea for some time now.

Also, nicely said Pete. Americans are the most fear-bent group of people on this planet. Stop watching American news… start watching Canadian news.. shit… you'll probably live longer. ) – by Johny-D

Stinky Pete(2:55pm EST Wed Sep 17 2003)Hmm, does this mean you have to relax as well? You are already thinking about it getting coopted for military use and it hasn't been built yet.

Everything is speculation until it's been built. But that's what this thread would be for.

Another case of the pot calling the kettle black. – by WW

Ahh….(3:02pm EST Wed Sep 17 2003)Once we make this cable….how do we get it out to the satelite? A ladder? Tie it on the back of the shuttle? – by Doc_Stihl

How to assemble?(3:16pm EST Wed Sep 17 2003)I imagine it would be in sections. Starting from the satelite they slowly build it towards the ground. – by Maybe?

space elevator is cool(3:18pm EST Wed Sep 17 2003)I truly think this is the NEXT BIG thing….Mars here we come…I hope I ride up with Sting…adoodoodoo adaadaadaa – by eric r

Hey(3:18pm EST Wed Sep 17 2003)Who will make the huge “Out Of Order” sign that will be required for an elevator this big? -)) – by d0geek

Ummm….(3:36pm EST Wed Sep 17 2003)If there's an elevator pulling something up from earth is it not also pulling itself down? Will there be huge engines on this thing or what? – by b0zak

Hit it with an airplane… It will cut the plane in half or thirds. And not be severly hurt.

At low altitudes where fire is supported (0-20,000 feet) there MIGHT be some damage. Not likely since the fuel and plane would be falling away from the ribbon unless it hit the building at the base. In which case, a few thousand feet of ribbon might evaporate (it's only 2 atoms thick unless woven of multiple ribbons…).

Nothing else happens. Doesn't fall (it's held up by that stretch on the other side of geosynchronous orbit).

The bigger problem is the junk in low orbit (though that could be eliminated by carring water to a level above low orbit and venting to the vaccum. As the frozen droplets fall they would be hit by the junk slowing it down out of orbit as well as deflecting it to the side).

It would be nice.

Read the book.– by old sampler

This Is a Joke(3:41pm EST Wed Sep 17 2003)This won't solve anything. It will just put a bunch of junk into space.

We need to reinvent propulsion. It's our only method to escape the planet.

NASA is a joke! They won't do anything thing significant in out lifetime.

The thing is reinventing propulsion is a cache 51. It's a threat to national security. Imagine a nuke or some other object achieving destination within mins. There goes central intelligence.

Bottom line, humanity is on the eve of destruction. We can choose for something unknown to end without the technology to escape or we can provide the tech ourselves to end it.

It's sad, but I can't see it any other either way. Our real problem is socialism. We can't get along on the Internet. – by Mpeg3s

by the way(3:47pm EST Wed Sep 17 2003)There are other methods related to space elevators that can be done sooner…

One is to use a 120 mile long ribbon in orbit. The ribbon rotates like a wheel such that the end toward the earch is moving at near 0 speed relative to the earth. Use this end to attach to a transport pod (at 70 miles altitude). The pod then rotates away from the earth. At the high end of the rotation it lets go (60 miles above the center of rotations) to reach a high orbit. Reverse the procedure to come down.

Momentum must be maintained, so some fuel will still be needed by the hub (center of rotation) to maintin orbital speed.

Other writeups use a hub with spokes attached to a wheel for the same thing.– by old sampler

Catapult(3:52pm EST Wed Sep 17 2003)Don't you think a space Catapult would be more fun? Plus we'd have the added bonus of using it to hurl giant rocks at countries like Canada. -)

Seriously, It's a cool concept but I think it's more likely that we'll come up with better propulsion systems before we could get a project like this 'off the ground' (no pun intended) Plus, independent spacecraft have the advantage of being a lot more versatile. – by jmac

re: b0zak(3:54pm EST Wed Sep 17 2003)“also pulling itself down..”

Yes and no. Yes momentum must be maintained, but not a problem for 10-15000 years. The engine keeping the elevator up is the earths daily rotation.

Momentum is conserved when incoming traffic matches outgoing.

More outgoing would reduce the earths rotation, makeing a day last longer (not detectable on any single transfer). Incoming traffic would speed up the rotation, reducing the length of a day. – by old sampler

Secondly, Arthur C. Clarke was the **scientist** and popular writer who — based on his ideas expanded from the work of a Soviet **scientist** about a “space elevator” — published the novel _The Fountains of Paradise_ in 1979.

Thirdly, fellow **scientist** and popular writer Charles Sheffield [who was a friend of mine as well as the Chief Scientist of the Earth Satellite Corporation] published his novel _The Web Between the Worlds_ about a “beanstalk” also in 1979.

Both of these men held double Firsts in Mathematics and Physics [our equivalent of simultaneously acquiring double Master's degrees as undergraduates] from the most prestigious universities in England.

I would also suggest reading David Gerrold's _Jumping Off the Planet_ series for a fully realized [and delightfully entertaining] exegesis of the dynamics and engineering problems inherent in a space elevator. – by JJ Brannon

RE: Mpeg3s(4:12pm EST Wed Sep 17 2003)“This won't solve anything. It will just put a bunch of junk into space.We need to reinvent propulsion. It's our only method to escape the planet.”

You must learn to crawl before you can walk or run. Right now there's very little incentive to develop long-distance space transportation because of the enormous costs of just getting into orbit. You're missing the whole point of the space elevator by being shortsighted here.

A rocket, any rocket, will use 90% of its fuel load just getting into orbit. A space elevator would eliminate this phase. Once in orbit, going at least orbital velocity (18,000mph) escaping orbit will be far easier. A space elevator could even be used to “slingshot” rockets on their way somewhere. Remember, the counterweight for the elevator will be in a geosynchronous orbit, moving at many times the orbital velocity of low-Earth-orbit satellites. Any craft lauched from the counterweight would receive this velocity for free, not needing any rocket power whatsoever. Far from your prediction, it would eliminate much of the need for more radical propulsion discovery!

But we still need better propulsion technology, which is where the space elevator comes in again. Right now, the best theoretical propulsion ideas revolve around nuclear principles. Unfortunately, you can't launch a fission (or a theoretical fusion) rocket from the Earth's surface without lots of environmental contamination. AHA! But if you didn't have to launch from inside Earth's biosphere, this limitation is removed! Nuclear propulsion, making use of an orbit-elevator slingshot, could make the Earth-Mars transit in just a month, but conventional chemical rockets launched from Earth need a year!

AIR DEFENSE!(4:24pm EST Wed Sep 17 2003)A simple Soloution to this. Definitly Install Devensive Missiles and restrict airspace around this thing. then no religious fanatic #@#*($@#5t can get near it, it would be great to see such a thing built, and im still young so i believe i will see this come to reality before 2030.

On planes to Stop Them Crashing into Builings, infustructures they should have the capability to be overrided somehow , How An Automatic Long Range Sensor To Avoid These objects giving no control to the User of the plane

– by Matt

Matt(4:27pm EST Wed Sep 17 2003)sorry mistake in last post,

planes Should Be overrided By Computer Control or High Security override If they were to head for a building, Installing a Smart Computer into a plane shouldnt be a problem , should it?

– by matt

No engine required(4:36pm EST Wed Sep 17 2003)Addressing the points of “what keeps this thing up in orbit”…have none of you ever twirled a rock at the end of a string? What keeps the rock whirling around instead of falling down? Centrifugal force, of course! Or, as purists would call it, inertia.

A space elevator would require a ground station situated somewhere near the equator and an orbit station placed in a geosynchronous orbit. Any object in a geosync orbit *stays* there. It orbits the Earth at the same speed the Earth rotates, thus keeping it over the same spot on the ground. Orbital mechanics would keep the orbit station up, not rockets or any other propulsion. Thank Isaac Newton.

As for those of you bemoaning “what happens when a hurricane this this thing”…again, you're not thinking too far along, are you? There aren't a lot of desirable land-based spots along the equator, but who says the Earth station has to be land based? The most feasible plans call for an ocean-based Earth station. This has a number of advantages. First, you don't worry so much about national sovereignty. Second, the platform can be movable to a certain extent. Hurricane coming? Move the platform. The orbit station counterweight could change orbit (within limits) to accomodate movements of the ground station.

Lastly, someone up there griped about the cable falling down and killing a lot of people. If it's in the middle of the ocean, it's not going to kill anyone, but in reality the cable would not fall — at least, not completely. If a terrorist sliced the cable at, say, 30,000 feet, the bottom 30,000 feet would indeed fall down, but the upper 424,080,000 feet would remain in place, anchored to the orbit counterweight.

In fact, this points out the logical way to design the system in the first place. Cable would not be made on the ground and towed up, it would be made in orbit and lowered down. If something catastrophic were to happen to the cable, more cable could be made, attached to the orbit end of the existing cable, and lowered down. – by J. Eric Smith

Ways to defend the cable against terrorists(4:44pm EST Wed Sep 17 2003)Missles and such might be of some use to defend the cable, but I don't see it doing much good from a short range perspective. Unless you completely destroy the plane a good distance away from the cable, any terrorist might have a chance to glide or crash-land a crippled plane into the cable.

What would most likely work is a large hemispherical “no fly” zone around the cable. Any aircraft entering this zone would be instantly intercepted and, if needed, shot down. If the ground station were located on land, this would not be too much trouble because it would have to be on the equator. There aren't a lot of really big cities near the equator. If the ground station were in the ocean, you'd have to send passengers and cargo via boats in order to preserve the no-fly zone. I suppose some radical fanatic yearning for his particular 72 virgins in paradise might try to sneak a nuke onto an ocean transport, but rigorous screening would likely make such an endeavor difficult to pull off — far more difficult than hijacking a plane. – by J. Eric Smith

Saturn V(4:47pm EST Wed Sep 17 2003)Forget Space elevators, just build a more powerful, modernised Saturn V! Space elevators are extremely boring! At least with the Saturn V you get plenty of noise and excitement, which you will never get with Space elevators!!! Space elevators will completely take out the thrill of space exploration! – by Dominic Pledger

Conservation of…(5:16pm EST Wed Sep 17 2003)angular momentum. Could you really move your object up the cable all the way to the counterweight “for free”? By conservation of angular momentum, shouldn't moving a massive object farther out from the axis of rotation require the rotation as a whole to slow down i.e. counter weight no longer at orbital velocity unless you kick it up a notch? I'm supposing you could use more efficient electrical means for moving objects up and down the cable, but wouldn't getting that weight to go faster require the same old chem rockets needed for propulsion in space? I suppose the fuel could be pumped up the center of the pipe or carted up, but it doesn't seem like it would be “free”. I might be wrong since this just occured to me, but it seems that the advantage of a space elevator would be potentially more efficient means of getting stuff up, but not getting stuff up without imparting the energy to that stuff one would otherwise have to have done. – by Binarius

…the big expense with the space shuttle is that it needs such vast volumes of fuel (Of course the enormous fuel tanks are extremely expensive as well). I think it should be possible to make space travel cheaper if you could launch the shuttle from some high mountain and with some high initial velocity attained by some cheap means(thus reducing the need for fuel, making smaller fuel tanks possible and everything gets cheaper).

My suggestion is to build a vertical tunnel inside some big mountain with some kind of vertical maglev track (needs only “cheap” electricity). The track will start at sea level and go to the top of the mountain (perhaps 5000 m asl) The shuttle will then be loaded on the maglev train/elevator which accelerates it to the top of the mountain and there releases the shuttle at 5000 m asl and with a very high velocity. A reasonable upward acceleration would be perhaps 5 m/s^2 which would give the shuttle an initial velocity of 220 m/s (800 km/h) when it leaves the elevator track. During every launch the tunnel should be pumped so the air pressure is the same as at 5000 m (perhaps 60% of sea level pressure). Maybe it would even be possible to create a vacuum in the tunnel so that the elevating vehicle won't experience any air resistance at all, thus making it alot easier to reach the needed velocity. As a safety precaution the shuttle itself should probably turn on its engines already at the bottom of the tunnel, but not give full gas until it is clear out of the mountain.

Of course this would be extremely expensive to build but since you could use it for thousands of launches it would be worth it. – by Svitjod

Why use a cable?(5:40pm EST Wed Sep 17 2003)If the cable is the main sticking point, why not use a hydraulic lift instead? – by Dust

Read the published info(5:42pm EST Wed Sep 17 2003)What happens if?

Edwards and his colleagues working on the concept have well-researched answers to your questions/objections already. Go to the ISR website () and read the papers.– by Patrick

LiftWatch.org(5:53pm EST Wed Sep 17 2003)We've just started LiftWatch.org, a news/portal site dedicated to discussion of space elevators and related technologies. Come check it out!

– by Chris

RE: Svitjod(6:01pm EST Wed Sep 17 2003)First off, the highest mountains on the planet represent the merest fraction of the altitude needed for orbit and space travel. Sure, a 15,000 foot peak puts you three miles closer to orbit…but orbit requires you to be about 54 miles up! Increasing the altitude won't help enough to matter.

Further, launch sites for anything leaving the Earth's surface need to be close to the equator. NASA doesn't launch shuttle from Florida because they like they weather. They do it because they use the Earth's rotation to “boost” rockets leaving the surface. This is why almost all rockets are launched in trajectories that follow the Earth's rotation instead of counteracting it. If you look on a map, you'll see there aren't a lot of mountainous regions located near the equator, and those that are don't exactly seem very hospitable.

The maglev launch system you mention is a viable technology, though. It would work, but has a number of drawbacks. First and foremost, there's Earth's atmosphere. Anything being fired from your electric launcher would have to overcome aerodynamic friction as well as the Earth's gravity. The payload would have to either be very small or the launcher would have to be very big — too big to be any more cost effective than current launch technologies.

Really, until we master an efficient form of antigravity, there's not going to be a more cost-effective way to get into space than the space elevator. It's just got too much going for it. – by J. Eric Smith

Elevator Music?(6:44pm EST Wed Sep 17 2003)The idea of magnetic launching is something that has been toyed with. The military has experimented with magnetic guns. The problems are 1. The power required to operate the magnets 2. Getting the magnets to temperatures low enough to become super conductive.

Also there used to be a program for using a giant gun to shoot small (150lbs) payloads into space.

One thing does scare me about the space elevator idea. Space elevator music. Can you imagine listening to elevator music for the length of time it would take to get 50 miles up? – by Chris

Discovery channel program(7:22pm EST Wed Sep 17 2003)There is a Discovery channel program that I saw a few months ago that described space elevators.

To call this thing a cable or a ribbin is an understatement. The show I watch depicted this cable similar to the main support cables of the Golden Gate Bridge, they looked like they were the thickness of a Greyhound bus. The lift was huge, it looked like you could put the whole space shuttle inside of it.

The show I watched also said the there are suspention bridges on the planet today that have as much cable in them as such a space elevator would.

I think the big hurdle is getting the strength to wieght ratio as high as possible for this to be practical. Hence the use of some super material to get it done. The article estimated around $7 billion, given that a submarine, a semiconductor fab, or a really big sky scraper cost about $1 billion I think $7 billion would be a bargan. Much better deal than a fleet of space shuttles at several billion apiece…– by space geek2

50 miles up @ 50 Mph = 1 hr(7:24pm EST Wed Sep 17 2003)I don't think going up 50 miles would take as long as people might think. If you elevator hit a top speed of 50 miles per hour (not hard to do), it wouldn't be that much longer than my daily commute… – by 50 miles

Classical forces(7:41pm EST Wed Sep 17 2003)Hmmm… I'd like to see the balance-of-forces equation for this thing, I bet it's pretty nasty. – by mathhead

Discovery and 50 miles(7:48pm EST Wed Sep 17 2003)Read Edwards' paper rather than trusting the Discovery channel. (Which I enjoy, but that's not the point.) The proposed elevator is about 3 ft wide at the widest point and about a micron thick. This much mass can be orbited by a few EELVs. A cable the width and density of a bus would require Star Trek technology to orbit, and in that case the elevator would be superfluous, hmmm? :)

But you are right, the only major question mark in the proposal is manufacturing a carbon-nanotube composite cable with the necessary strength, durability and light weight. Everything else is standard aerospace engineering, pretty much.

Secondly… where did the 50-mile figure come from? The elevator as proposed can take payloads to, and release them from, any point along its 62,000 mile length. Payloads released from the end would have enough energy to go to the outer planets.

Patrick – by Patrick

One more nit(7:55pm EST Wed Sep 17 2003)While the cable is 60-something thousand miles long, most of it is above geosync, which is at about 22,000 miles rather than 64,800 as stated in the article. – by Patrick

Lol(8:02pm EST Wed Sep 17 2003)And When The Cable Breaks (1:49pm EST Wed Sep 17 2003)if they can create such a cable, it comes crashing down killing thousands. – by The Shaft

Actually, the cable comes down killing thousands (maybe), the satellite remains in its geosynchronous orbit.

I like this idea for anti gravity, but this doesn't bring us any closer to a technology to be used for NASA space exploration. I doubt this thing would be able to bring up a spacecraft to transport astronauts to mars or the moon for example. It would primarily serve as a tourist attractions. Sure, I would go, but would it really be anymore useful than the statue of liberty? And how would you stop a terrorist from simply going and blowing up the wire or flying into it with a plane? Just my 0.02 – by Mystix

gut level MTBF(8:14pm EST Wed Sep 17 2003)Every system has a MTBF (mean-time between failures) that is estimated in part by the number of things that can go wrong. The 5M SqFt fabric area and corresponding number of molecular bonds must surely* exceed the complexity of the relatively tiny Space Shuttle with its reliability-challenged O-ring seals and heat-deflecting tiles. Which would you rather inspect? How would it hold up under Isabel? K.I.S.S. (Keep it simple stupid.)

*but not necessarily – by ElectRon

This Idea doesn't make any sence(8:51pm EST Wed Sep 17 2003)

think how big this object has to be to maintain orbit while elevating things into orbit

unless you use something Really big and heavy it will be using a lot of fuel Just to maintain orbit.

ramp(11:15pm EST Wed Sep 17 2003)what happened to the ramp idea? the one where the object to be sent into space is launched off a ramp (sling shot???) i forget the term. – by aggg

Re:Bill(11:41pm EST Wed Sep 17 2003)Why would it need to use fuel to maintain orbit? the moon seems to do a good job without fuel, and I think it is bigger than anything involved in any plans for a space elevator. Or how about the Earth, it doesn't seem to need fuel to orbit the sun. – by someoneelse

Carbon Nanotubes are stronger than airplanes(12:29am EST Thu Sep 18 2003)Why are we worried about people flying planes into this thing. If it can support 10000km of its own weight + counterweight it wouldn't cost much extra to make the bottom few km a little thicker to survive aircraft impact. A aluminium aircarft would be cut in half. – by mmdcnt

re:Lol (12:59am EST Thu Sep 18 2003)“I like this idea for anti gravity, but this doesn't bring us any closer to a technology to be used for NASA space exploration. I doubt this thing would be able to bring up a spacecraft to transport astronauts to mars or the moon for example. It would primarily serve as a tourist attractions. “

I think you miss the potential here. Wouldn't they be able to dock space ships at the station that the cable leads up to? Passengers could take the elevator up to the station and then board an already orbiting space craft. The only problem now is fueling it. – by elite

Ignorance(1:58am EST Thu Sep 18 2003)The elevator pad will be built int he middle of the ocean far from any airline routes. This has been said so many times in the history of the project. Besides an airliner hitting a cables as hard as diamond would result in a sliced in two airliner with a nice guitar note emiting from the cable. (or something like that).

If the cable ever snapped, it would launch out in space nver to be seen again, like someone stated above, tie a rock to an end of a string and swing it around…. what happens when if the string breaks? Does the rock and string come to you? no.

Obviously the cable station would have defences, the only real threat regarding location is submarines. – by simplistic minds

answer(2:02am EST Thu Sep 18 2003)“I think you miss the potential here. Wouldn't they be able to dock space ships at the station that the cable leads up to? Passengers could take the elevator up to the station and then board an already orbiting space craft. The only problem now is fueling it. – by elite”

An already orbiting shuttle would require very little energy for momentum while in space. A docked shutle could use solar power perhaps, or the same system that will power the elevator, Laser. The elevator will be powered by laser being shot at a unit that will collect the energy from the laser beam. No reason a “space ferry” couldnt do the same. – by simplistic minds

What about such a “elevator” as a power-source?(3:10am EST Thu Sep 18 2003)Couldn't one use the different electrical potentials between ground level and the upper end to harvest big amounts of energy?

I read something like that about future satellites using long “tethers” to get power…

Sponsored by Great AdventuresTheme Parks(4:41am EST Thu Sep 18 2003)OK if it fails, I hope Great Adventures bids for this elevator thingy to be the worlds (Universe) longest Free Fall Ride there is! What fun….comming down to earth with charcoal griddles on our cheeks! hahaha – by LMB

Engine Noise(5:44am EST Thu Sep 18 2003)There is nothing like the noise of five F-1 engines at full thrust!!! Resurrect the Saturn V at once!!! – by Dominic Pledger

Isn't it Rocket Science?(5:50am EST Thu Sep 18 2003)Ok, let's suppose it is all buildable now, including the lift “Cable”. Would it really be more efficient?

As the load is lifted will it not attempt to pull the top station down, thus affecting it's orbit and therefore it's geo-stationaryness (to possibly coin a new term). If the top station is to maintain it's position it will have to use fuel. How is this fuel any different to the fuel used in getting a standard rocket into orbit? I first thought “A rocket has to lift the payload as well as the fuel”. But wait a minute, this fuel is already up there in space, so it had to be lifted up there.

So, how about the Earth end of the cable is not fixed to anything. The payload is attached (using a scoutish application for knot tying) to the end and the top station alters it's orbit to move away from earth. Would this be any more efficient? The load is lifted from earth, but energy has to be imparted at the top end to make it happen.

Where are the energy savings? – by Confused

Whoa(7:35am EST Thu Sep 18 2003)Now I see what they are going to do. This huge lump of space station will be whizzing around tied to planet earth via the cable or ribbon. So as long as the climbing load doesn't impart more downward force than is already apparent as an upward force in the cable itself……

Hmm, I hope they can release the cable from the bottom end pretty quick, cos if the top station goes walkabouts it will be like a conker on the end of a piece of string.– by Still Confused

I Repeat…(10:48am EST Thu Sep 18 2003)Go read _Jumping Off the Planet_, _Fountains of Paradise_, & _Web between the Worlds_ if you don't want to slog through technical papers.

THese highly entertaining novels all do an excellent job of informing one of the engineering constraints, physics, and energy production capabilities of beanstalks.

David Gerrold said to me just before Christmas last year that he regularly taps the expertise of a nuclear engineer he knows who looks like someone's kid brother.

When people see them together they ask David who his friend is and he's always confusing them when he says his buddy's a military officer and nuclear engineer, with a Ph.D. in nuclear physics.

I really think it would be a short sighted solution to the problem and clean, safe, efficient vehicles will be around before it could be done. But that is just a guess. I am assuming that the future holds technologies that will be far more efficient at getting payloads in to orbit and beyond. Technologies that involve vehicles. All really speculation. The engineering problems are enormous, complex, and even the expets do not fully appreciate all of them yet I am sure. It will be interesting to see how this develops.

There will be commercial flights to space soon and not long after that commercial orbital flights. The engines (clean burning by the way) have already been full burn tested. With such things on the horizon it is hard to justify such a huge engineering exercise. But it is interesting. – by Astronut

I Love This Stuff(12:10pm EST Thu Sep 18 2003)I love this stuff.

Building a space elevator, the sooner the better. Designing the technology to build it, the sooner the better. Imagine standing in South America or Africa and seeing a perfect verticle line stretching into the sky, unwavering. They will even sprout out of the Oceans.

A mound of a city apearing from nowhere centered on this artifact. New economies, new social structures, new possibilities. Yes terrorism will always be a threat but it will be just another problem to be solved. The technology that can build such a thing will also be able to break it. If one is built more will be built thereafter.

Oh by the way, it will probably have to be built all in one piece, in space. Once the first is deployed why would the builders stop with just one? Why would they stop with Earth? They will sprout from our Moon, Mars, Venus, Mercury, IO and all the engineering problems for each will be solved.

I love this stuff, the sooner the better. – by Big Al G

Re Confused(12:29pm EST Thu Sep 18 2003)that was exactly my point

they will have to use fuel and rockets anyway – by Bill

“The spirit that fired Apollo is dead.”(1:24pm EST Thu Sep 18 2003)I'm suprised no one has commented on this yet.

The Soviet Union is indeed dead.

Let's not forget in our “noble space exploration” fervor that the reason we got to the moon so quickly was simply to beat the Soviets there. There has been little or no competition in space exploration for over a decade.

The idea (idealistic concept?) of a space elevator in the middle of the ocean (so there are no soverignty issues) is nice, but that means no nation will fund it. That leaves corporations or a group af nations as the only possible backers, neither of which will happen without the (exclusive) economic benefits being shown long beforehand. – by JRink

I have an Idea(1:43pm EST Thu Sep 18 2003)Why not nuke all of the middle east, flatten it out and build the elevator there?? – by WD

hello(3:37pm EST Thu Sep 18 2003)This idea has been around since the 1950s, but has been firmly beyond our reach until the bucky-ball was discovered in the early 90s. The biggest problem to this plan is of course weight, since this elevator would have a total length of 60,000 feet. thanks, got to go. the damn professor is making me leavebye- – by joe

Confused(4:04pm EST Thu Sep 18 2003).. please do what JJ Brannon said in the earlier post…but in a nutshell – do elevators in large building need huge amounts of fuel and rockets… anyways – same principle – counterweights and balance – could be done in two ways – with a counterweight that would be lowered and raised at the end of the rope (beyond the satellite) or exactly like an earth elavator works – one comes down while another goes up. – by snipe

think how big this object has to be to maintain orbit while elevating things into orbit

unless you use something Really big and heavy it will be using a lot of fuel Just to maintain orbit.

i guess you would be pumping the fuel from the ground

well – that might work even if its small – by Bill———————————–—Re Confused (12:29pm EST Thu Sep 18 2003)that was exactly my point

they will have to use fuel and rockets anyway – by Bill———————————–—It will require no fuel to stay in orbit at all, take a string and wizz it in circles at 10000 km/h or so with a weight tied to the end. (providing the string does not break) You would have a hell of a force pulling from your arm. The space elevator works in the same way. It could easily hoist heavy loads.

Now why would rockets and fuel be needed? The space elevator will have its own motors, it will climb the ribbon with potentially large rubber rollers that grip the ribbon. It will not have any power cords, cables, pulleys or counter weights or any sort. It will be an independent climber. Its power will come from a laser at the base station that will beam power into a power converter onboard the elevator.

Snipe, this is how it will work, none of the ways you mentioned. ) They are all way too impracticle.

– by simplistic minds

Re: J. Eric Smith(4:49pm EST Thu Sep 18 2003)About my “maglev elevator” idea. You are probably right that it wouldn't make a very big difference just putting the launch a few kilometres asl. And the initial velocity will only carry the shuttle another 2-3km up or so, so it wouldn't matter much. Probably the cost of building such a thing would be as expensive as rebuilding Iraq, so it won't happen. About equatorial mountains. The Himalayas are at about the same latitude as Florida and surely there must be some high mountains in indonesia and south america. Perhaps you could even use the volcano kilimanjaro in kenya! )

About the space elevator idea, I agree it's a really cool concept. However, I would be gladly surprised if it was built during my lifetime. I believe that if it's ever built it will be built by Red China which I think will be the real super power in this world some 30-50 years ahead. I've heard that the chinese are planning to send some men to the moon in a few years time. At least they are willing to put some money into space research, and their economy is getting stronger for every day (which is hardly true for the US and Europe). – by Svitjod

Simplistic(4:54pm EST Thu Sep 18 2003)…says…It will not have any power cords, cables, pulleys or counter weights or any sort.…Assuming that the weight of the elevator car is insignificant in proportion to the weight of the cable then you could be right – however I don't think it will be that simple..If you simply took a weight and 'wizzed' it around the earth it would take a hell of an anchor to keep it grounded (read impossible) Surely it would be easier if you let the cable below the geosync orbit balance the part above the geosync orbit – then it would simply float above ground. – by Snipe

Pulleys(5:08pm EST Thu Sep 18 2003)BTW: I did not mention any pulleys – I simply said as one weight goes up another most move down the cable (if both are below the geosync point – if you put one weight above the geosync point then you would move both up or down though at different rates to keep the total cable balanced around the geosync point) – by Snipe

Snipe, and others…(6:20pm EST Thu Sep 18 2003)Why don't you save yourself a lot of head scratching and useless speculation, and go read the paper?

Perhaps you will convince yourself that Los Alamos physicists really can do physics. :) Also it's a fun read. – by Patrick

RE: Patrick(9:21pm EST Thu Sep 18 2003)Thanks for that link…While I am convinced that Los Alamos physicists can do physics I also believe they do make mistakes…

What I wrote is correct. The cable has to be in gravitational balance between the earth pulling it down and it's rotation pulling it away. It is not simply matter of taking a heavy object and twirling it above earth.

However, with statements such as “shorter the cable the larger the counterweight mass required with it eventually reaching infinity when the cable only reaches geosynchronous.”.. from the paper at the link provided… What would happen with a very heavy mass (one approaching infinity) is that the geosynchronous point of orbit would get closer and closer to earth.

So while it may be armchair science, I rather like to debate and discuss and I still don't appreciate being told to shut up and let the 'real' scientists figure everything out. – by Snipe

I Got The Solution(7:07am EST Fri Sep 19 2003)This is a joke, OK?

Why don't we tie the cable to the Moon?

– by Mpeg3s

Snipe(9:29am EST Fri Sep 19 2003)Your last statement [and the interpretation of the excerpt from which derives] seems to miss the concepts.

[Once again, this is all covered in the novels I mentioned, and in Charles Sheffield's non-fiction Borderlands of Science.]

The nanofilaments are grown/extruded up and down from a geosynch satellite so that the mass-centroid lies in a stable orbit.

The spinning string example is accurate, requiring >40K miles unless a large counter-mass — such as a small asteroid is added to the orbital terminus.

Geosynch doesn't change, but to balance the mass-velocity equations, the closer the counter-mass is to the geosynch fulcrum, the larger it must be.

Imagine a seesaw/teeter-totter with a 70-lb kid 4' feet from the swivel-axis [280 ft-lb] and yourself with on the opposite shrinking torgue-arm.

Neglecting friction, at 2' you need 140#, at 1'->280#, 6″->560#, 3″->1120#, 1″->2240#, and at 0″-> infinity.

No, you don't fuel. A beanstalk collects a stupendous amount of energy not only from kinetic effects, but from whipping through Earth's magnetic field at >1000 mph[surface] or >7000 mph [geosynch]. We will neglect extra-atmospheric solar cell surfacing as trivial compared to the other effects.

A beanstalk is a power-generator able to support several small nations.

Once a beanstalk is built, the fuel needs for a lunar trip are reduced by a factor of 1000 at least.

However, the construction cost will probably be in excess of four trillion dollars. – by JJ Brannon

Hey Snipe…(1:53pm EST Fri Sep 19 2003)No offense didn't mean to say you should shut up. Just that there is a lot of available information that clears up many of the questions posed on this forum.

The swinging-string analogy is not complete, because other forces are at work with the space elevator–namely, the earth's gravity. The elevator isn't just held up by centrifugal force, it's in orbit around a massive gravity-generating body. A guy swinging a bucket on a string doesn't exert sufficient gravitational force on it to noticeably affect its motion. (Theoretically, yes practically, no.)

There's a lot of math involved in describing orbits, but for the se it boils down to the fact that for any planet, there is only a single orbital altitude at which an object can be geosynchronous, and for the earth that is at about 22,400 mi. or so. Anything lower, and a posigrade object drifts to the east as seen from the ground, because its angular velocity is greater than the rotating earth's anything higher, and the object drifts to the west as seen from the ground, because its angular velocity is lower than the earth's. (This is why the moon is 15 degrees further west in the sky every night.) And an object that stays motionless in the sky with respect to north/south must also have zero inclination to the equator–geostationary (GEO). The se is actually a satellite in geostationary orbit–a very looonnnggg satellite, sufficiently long that its bottom touches the ground. To pull that off it must have a counterweight above GEO such that the center of mass remains in GEO. – by Patrick

insert a semicolon(1:56pm EST Fri Sep 19 2003)This site doesn't seem to like semicolons, and I like them a lot. So in my above post, insert semicolons where things seem to run together–for instance, after “No offense” and “rotating earth's.” – by Patrick

Speak Your Mind

caseyctg

As far as the power and energy concern…they are going to use maglev. It takes a fraction of the energy..it could be powered low cost, and it can have backup batteries that could power it long enough for an emergency. It is also very fast. They already have a maglev train in japan, nearing 400 mph. Boost the magnets and the power a bit and you have yourself a way to go up, lets hope that CNT holds…Also, how much radiation is in space??? Put a powerdock on the end of the cable (or asteroid), build some sort of rocket power on the space station that fuels itself by the immense radiation in space, solar power, solar wind, etc….that way, IF the cable breaks, the thing doesn't go flying away or hurling a cable down to earth…well, the cable could even have Helicopter dock stations while in our atmosphere too, just in case the cable breaks. Extra support to shut up the worry warts. With a flying power station on the other end of space, it opens up the idea of a space resort (which is being concepted & developed by hilton)