Thread: space elevator

I just saw a show on the science channel called 2057. They talk about what it'll be like in 50 years and they were talking about a space elevator. I didn't think it was possible to make one but they are saying it is. There plan is to use nanotubes and attach them to an oil rig in the pacific and attack the otherside to a counterweight outside our atmosphere. Through cintrifical motion the nanotubes would stay taught. I wasn't quite sure what they said about propelling the elevator up the nanotubes but it was something about shooting high energy particles at a solar pannel at the bottom of the elevator. The trip would take half an hour. What do you guys think?

it's seems a bit silly, after all one gust of wind and...

thats what I thought... but they said it was actually possible. They said they took thunderstorms and debris in outerspace and a whole bunch of other things into consideration

they'd need to clean up space a bit with a vacume cleaner, hahahaha, get it, VACUME cleaner, no? oh well, sometimes intelligence is wasted on you people, any way, where was i? oh yes, what about lightning storms hitting it, that wouldn't be pleasent to be inside.

they said they did a lot of observations and the spot they chose to put it in gets very few storms

In 1936 they said by the 1960's we'd all be in flying cars.
1n 1976 they said by the year 2000 we would all have domestic robots doing all the chores.

In 2006 they said we'd have a space elevator within 50 years...

Am i the only one walking around in tin foil suits like those predicted in the 50's

Talking of getting into space, whatever happened to the project of firing lasers at a donut shaped craft? I remember seeing the initial tests with frizbee sized objects, they sort of worked well

ok i do believe that it could be possible, but that kind of endeavour would have to face enormous adversities, like storms, rain, wind, metal stress and fatigue, corrosion, just by naming a few...new materials would have to be developed to make it possible...

Originally Posted by captaincaveman

whatever happened to the project of firing lasers at a donut shaped craft?

Are you sure you don't mean donuts firing laser shaped craft?

Seriously though, those guys have gone onto something bigger now, called a space lasso.

Yes it will probably be constructed when nanotube structures can be produced on an industrial scale instead of the minute lab experiment scale as was achieved some time ago

it will sway like modern highrise buildings in a way that makes me crap my pants

Originally Posted by Megabrain

Originally Posted by captaincaveman

whatever happened to the project of firing lasers at a donut shaped craft?

Are you sure you don't mean donuts firing laser shaped craft?

Seriously though, those guys have gone onto something bigger now, called a space lasso.

i found a link to it

http://gopaultech.com/2006/02/laser-...ve-propulsion/

theres video footage there too worth checking out .its really amazing stuff :-D

Originally Posted by U-BoaT

ok i do believe that it could be possible, but that kind of endeavour would have to face enormous adversities, like storms, rain, wind, metal stress and fatigue, corrosion, just by naming a few...new materials would have to be developed to make it possible...

The highlighted items would effect less than .25% of the length of the elevator. Moreover much of this could be avoided by terminating the elevator at, say, 50,000' and shuttling between Earth and elevator with normal aircraft.

The elevator offers the only efficient way of getting out of Earth's gravity well. Once in Earth orbit the Solar System is ours.

A sort of Captain Scarlet-ish aircraft carrier in the sky but suspended on a cable leading to orbit! :-D

holy cow,

I hope I live long enough to see this! :-D :wink:

Originally Posted by Ophiolite

The highlighted items would effect less than .25% of the length of the elevator. Moreover much of this could be avoided by terminating the elevator at, say, 50,000' and shuttling between Earth and elevator with normal aircraft.

I'm trying to imagine the physics that would allow this to be stable, but I'm having a hard time doing it. Since orbital velocity decreases and orbital period increases as you move away from the earth, it seems like the elevator would slowly wrap itself around the earth as the bottom of the cable starts to "out run" of the top of the cable. What am I missing?

maybe the counterweight has a propulsion system?

I used to watch "tommorrow's world" tv show here in the UK. I was really conned by that show !!

Where are my hover shoes ?

heh

but im not trying to say we will have a space elevator in 50 years. I'm asking if you guys think it's possible and what you think about it.

no. id give it more like 300 years. and only if we are still around then. which i very much doubt.

Originally Posted by Scifor Refugee

I'm trying to imagine the physics that would allow this to be stable, but I'm having a hard time doing it. Since orbital velocity decreases and orbital period increases as you move away from the earth, it seems like the elevator would slowly wrap itself around the earth as the bottom of the cable starts to "out run" of the top of the cable. What am I missing?

The centre of mass of the cable is at the geostationary point in orbit, so that it rotates around the Earth at the same time as the Earth turns, thereby remaining over the same spot. Some plans call for using a small asteroid as ballast.

Originally Posted by Ophiolite

Originally Posted by Scifor Refugee

I'm trying to imagine the physics that would allow this to be stable, but I'm having a hard time doing it. Since orbital velocity decreases and orbital period increases as you move away from the earth, it seems like the elevator would slowly wrap itself around the earth as the bottom of the cable starts to "out run" of the top of the cable. What am I missing?

The centre of mass of the cable is at the geostationary point in orbit, so that it rotates around the Earth at the same time as the Earth turns, thereby remaining over the same spot. Some plans call for using a small asteroid as ballast.

Ah, I see - I didn't realize that that cable was actually supposed to be "supporting" its own mass. The tensile strength would have to be pretty crazy. I suspect that by the time we can make a material like that, the world will already be a very different place.

apparently a carbon nano tube is so strong that a (large) cable could be used for a space elevator (or so they said in a report I saw, but carbon nano tubes can only be manufactured in a lab in small quantities for now.

Originally Posted by icewendigo

apparently a carbon nano tube is so strong that a (large) cable could be used for a space elevator (or so they said in a report I saw, but carbon nano tubes can only be manufactured in a lab in small quantities for now.

I have a sneaky feeling it will be another one of these 'wonder' materials promising a revolutionary new world, but in fact ends up being used as something like a new kettle element, and perhaps golf club shafts - or ladder proof stockings, shopping bags that don't tear.... :wink:

Just like computers really, promised a new world - we end up with windows - which plays games and plays music but does 'Far call' for humanity!

Hello,

New here..

My wonder is why make a space elevator in the first place? What would be the purpose?

it's a quick and easy way up into space, no rockets, no depris and little danger. It would also be a good place to stick a telescope (no light polution) plus it would be good for the economy because people would pay to say they have been into space

Originally Posted by Nevyn

it's a quick and easy way up into space, no rockets, no depris and little danger. It would also be a good place to stick a telescope (no light polution) plus it would be good for the economy because people would pay to say they have been into space

Only real snag is that cos a pair of crank Phd's say it's possible people follow them like rats after the pied piper!

Nanotubes at the moment are no more than the size of drinking straws for amoeba!

true, i really should have put it as a hypothetical

You'll learn I'm a cynical old sod at the best of times, it will not happen in my lifetime, though after I've been incinerated I might end up as part of it!

And if I am - it'll be the part that snaps, just to prove I'm right ie it's a crazy idea!

Originally Posted by Nevyn

it's a quick and easy way up into space, no rockets, no depris and little danger. It would also be a good place to stick a telescope (no light polution) plus it would be good for the economy because people would pay to say they have been into space

Yeah you are absoltely right !! What a FANTASTIC idea of sticking a telescope in space. You might have been on to a serious winner of an idea there !! That is if NASA hadnt thought of it already and put one there !

Its called Hubble. :wink:

I love the idea of the elevator. It would allow the transport to space of nuclear materials without the risk of a rocket exploding...spreading radioactive material over half of Florida.

Off topic question:
If you put a nuclear reactor in space and essentially poked a hole in the side of it and let some of the reaction out and controlled it...would it make a good engine?

Originally Posted by leohopkins

Originally Posted by Nevyn

it's a quick and easy way up into space, no rockets, no depris and little danger. It would also be a good place to stick a telescope (no light polution) plus it would be good for the economy because people would pay to say they have been into space

Yeah you are absoltely right !! What a FANTASTIC idea of sticking a telescope in space. You might have been on to a serious winner of an idea there !! That is if NASA hadnt thought of it already and put one there !

Its called Hubble. :wink:

I know, i know, but i was coming up with ideas for LightningBird and was quickly running out of things to put, and besides, it's an easy way to put a telescope into space, check it's working(cough,hubble,cough) fix it easily and then release it

Originally Posted by MacGyver1968

I love the idea of the elevator. It would allow the transport to space of nuclear materials without the risk of a rocket exploding...spreading radioactive material over half of Florida.

If you can get a ticket with all those christains in the queue...

Originally Posted by MacGyver1968

Off topic question:
If you put a nuclear reactor in space and essentially poked a hole in the side of it and let some of the reaction out and controlled it...would it make a good engine?

off topic answer:
secondly yes, but it's more subtle than 'poking a hole in it' - google it I forget what it's called 'nuclear powered thrust' might get you there.
It was tried but the nuke ban halted that.

I hope they really improve nanotubes so they could use them to make an elevator in my lifetime! It would revolutionize travel to outer space.

Originally Posted by Scifor Refugee

Ah, I see - I didn't realize that that cable was actually supposed to be "supporting" its own mass. The tensile strength would have to be pretty crazy.

Steel has a tensile strenght of around 1 GPa. Carbon nanotubes have been made with a strenght in excess of 60 GPa.
Source: Min-Feng Yu et. al (2000), Strength and Breaking Mechanism of Multiwalled Carbon Nanotubes Under Tensile Load, Science 287, 637-640

Originally Posted by MegaBrain

Only real snag is that cos a pair of crank Phd's say it's possible people follow them like rats after the pied piper!

Once again MiniBrain is confusing sarcasm with objective analysis.
It is unclear whether his objection is to the concept of the space elevator, or to carbon nano tubes, or both.
Let us examine his claim that the first of these concepts is based upon the thoughts of 'a pair of crank PhDs.

The idea was originally proposed by Tsiolkovsky, the father of rocketry and space flight. A more detailed proposal was made by Yuri Artsatanov, a reputable Russian engineer.
The concept gained popular attention following a novel - The Fountain's of Paradise - by Arthur C.Clarke. You know - the 'crank' who proposed the concept of geostationary communications satellites.

The Marshall Space Flight centre held a conference in 1999 to review aspects of building and operating a space elevator. You know the Marshall Space Flight Centre - those are the cranks responsible for rocketry and the like within NASA.

I could go on, and will do if required, or requested. The bottom line is that the space elevator is not a wild, nonsense notion, but one that is well founded in science, and for which the engineering is being systematically developed.

Of course human progress has been routinely interrupted by those lacking imaginations and who choose to live in the past, so I shouldn't really be surprised by MiniBrain's take on it.

My opinion that the space elevator is a crackpot idea is, not unreasonable. Although such a system may be theorectically possible I believe other technologies will supersede it. In the field of superconductivity, real progress is being made towrds materials which will superconduct closer to 'room temperature' these are complex compounds which so far have raised that temperature to around 120K [if I remember correctly].

In the aerospace field materials are constantly under development which will withstand both the temperature and forces necessary to survive an unpowered launch to orbit, and a steeper decent angle than is currently used.

Modern breakthroughs in Power semiconductors alllow switching times which are far shorter than previous. Switching times were typically measured in micro/nanoseconds. Switching times less than 1 pico second have now been demonstrated.

I fully expect within 10 to 20 years all of the technology will be fully developed to build a sytem which could launch an engineless cargo vehicle into earth orbit.

In 2003 the Japanese propelled a train at a world record speed of 581Kmh. The next generation Linear system could easily launch a vehicle every 30 seconds [plus whatever interlaunch inspection time is required].

That is why I contend the space elavator is 'crackpot' as well as the 'catastrophic failure syndrome'. The earht based magnetic launcher presents far less maintenance problems, and gives the vehicle an initial velocity which is maintained once in space. If you want to move on from your asteroid you will still need a rocket to accelerate you from a 'near zero' initial velocity.

http://archives.cnn.com/2002/TECH/sp...hes/index.html

as i understand the concept, the estimated cost are out of line for the value of results. while nanotech, is making progress, this same progress is also in miniaturizing whats required to manufacture items. its not inconceivable, one moon (some day) shot could carry a refinery and/or other things to produce on the moon, what most envision the elevators missions. likewise a single malfunction, in one very costly project could create more problems than are being discussed.

personally i hope study and test continue on SE, as nanotech will. to envision is the future of science, although i will question who is or is not qualified. to many folks are blinded by their educations, piers, social structure and even worries of upsetting some financing group or social organization. this also means efforts to think of a proposed idea, for lack of creditability.

Just for the record - the highest superconductivity critical temperature recorded is unofficially 150K and officially 132K.

For info on the 150K superconductor see http://superconductors.org/150k_pat.htm

Originally Posted by Megabrain

My opinion that the space elevator is a crackpot idea is, not unreasonable.

On the contrary: it is wholly unreasonable.

A crackpot idea is defined as foolish or harebrained. As I have amply demonstrated, these ideas are well founded in science and engineering. Yes, they push the envelopes of what is currently possible, but that is true of much good science and engineering.

You may dispute the economic viability of the concept; you may question its potential for failing catastropically; you may cite alternative methodologies that are to be prefered; but you cannot, if you have any respect for the meaning of words in the English language, call it a crackpot idea.

There comes a time for all of us to accept the new and throw out the old, your post suggests a reluctance to do this, space elevator may once have seemed a fair proposition but in your post you do nothing to defend it, or promote any advantages over the newer megalev system.

Now assess the two systems objectively and tell us honestly which one would you invest in?

MegaBrain, I am favouring neither. I simply objecting to your misapplication of the term crackpot theory to the elevator, and your claim that it was dreamt up by a couple of crackpot PhDs.
That was pure unsubstantiated rhetoric. I called you on it. Have the good grace to admit you were wholly unobjective, misleading and downright wrong.

Your post implies I used either or both the terms "crackpot Phds" and "crackpot theory", neither term can I find in my posts in this thread.

THe words I used were "crank phds" crank in this sense being 'eccentric or peculiar'.

On the occasion I did use the word "crackpot" it was in the present tense, in the knowledge of cheaper, safer, more efficient alternative systems. It is my opinion that to continue supporting the space elevator [other than as a theoretical exercise] is crackpot, that is, foolish or hairbrained.

Crank/crackpot etc etc.

I have not checked the exact wording you have used in these earlier posts since your meaning was very clear.

You maintained the idea was foolish and supported by only a couple of eccentrics. That is not the case. You were wrong, no for *****'s sake admit it, so we can move on.

Let me be clear. Crank phd is what I said, and that is what I meant. NOT crackpot. It may be that people ascribe the words as meaning the same, that's not my problem.

Now back to to space elevator, I do not see it happening now, or at any time in the future. The satellites that provide us with TV are mostly in geostationary orbits, yet each of these requires daily adjustments in their positions*, this is achieved [in modern systems] by using low power ion drive engines. An asteroid in a captured orbit would also require regular minor adjusments, since it's mass would be large so would the energy requirements. The initial energy of 'netting' an asteroid, guiding it towards earth, adjusting it's velocity for a geostationary orbit, positioning it an equatorial orbit, might even require more energy than it could 'save' over it's useful life period.

NASA actively supports research into 'nanotubes' this may not be for the primary reason of creating a space elevator. Carbon nanotubes are likely to have other applications in space, perhaps for providing a frame for spacesails, the strength of this material may find a use as a barrier to MMD (micro meteoroid damage). It may even offer better thermal protection.

I have tried to find links of NASA actively funding a space elevator but have failed [other than NASA 'considering' the idea]. THe Magnetic launcher however they have put money into as my previous link shows.

Practically, I see the idea of a space elevator only occuring when the problems of mass propulsion are advanced beyond what any of us can currently envisage by which time the need for it will no longer be required.

It is needed today, it is not practical today.

* these adjustments are required to overcome the gravitational effects of the moon, solar winds, and other minor perturbations of their orbits.

Originally Posted by Megabrain

Let me be clear. Crank phd is what I said, and that is what I meant. NOT crackpot. It may be that people ascribe the words as meaning the same, that's not my problem..

Your problem appears to be that you don't know when you are beaten. Goodnight.

we are each entitled to our own perceptions and points of view. - sweet dreams.

This video might make you laugh when you see the speed of the elevator in action

http://www.youtube.com/watch?v=gyBJvx2FaGw


heres a site about space elevator
http://www.pbs.org/wgbh/nova/science...01/02-why.html

15 to 20 years did he say?.

Originally Posted by shawngoldw

I just saw a show on the science channel called 2057. They talk about what it'll be like in 50 years and they were talking about a space elevator. I didn't think it was possible to make one but they are saying it is. There plan is to use nanotubes and attach them to an oil rig in the pacific and attack the otherside to a counterweight outside our atmosphere. Through cintrifical motion the nanotubes would stay taught. I wasn't quite sure what they said about propelling the elevator up the nanotubes but it was something about shooting high energy particles at a solar pannel at the bottom of the elevator. The trip would take half an hour. What do you guys think?

Ha ha ha !
This defies logic, let alone physics.

Lets see a nanotube cable or ribbon, what ever its size, mass and weight, will require an anchor greater than an off shore oil drilling platform. It would also require a reel to hold the cable, and be able to deploy same at a fast enough rate. (the empty reel would be part of the anchor system)

What is the attachment point? (a sky hook?) And what is used to lift it into space? (a sky hook rocket?) And maintains it's position above the anchor point, while turning with the earths rotation. While not being affected by solar flares, and radiation.

An elevator space craft, large enough and light enough, to transport a payload of what? What size? what weight?
A 12'x 12' x 40' container, a payload of 10,000 lbs, 40,000 lbs? or 4,000 lbs which would be hardly worth the effort and cost. The space anchor point, would have to adjust its position per a payload, while the payload traversed the cable to the point of weightlessness, within its safe limits of tensile strenght of the cable itself. And how much fuel would the geosynchronous satellite sky hook, store and use in the whole process, during its lifetime.

And after its lifetime, how will it be dismantled, and scraped. When a better air/space craft is built, that makes the elevator obsolete. We will never tether the Moon or any other planet. This is a nano-pipe dream! Our resources and investments are better tethered, on propulsion engines and fuels. And set our thinking, on Moon based construction facilities and stations between Earth and the Moon. Life support and spacecraft shielding from moon concrete, and ceramics. Moon based robotics and solar power stations, design electrical conponents, robots can assemble and maintain with logic circuitry interface for I.D. and traceablity scans.

You don't think the designers of the space elevator, will be the first ones to go up do you?

Okay, they want to make carbon nano-tube ribbon, which may be possible in the near future. They are not planning on using rockets as that sort of takes the whole point out of using an elevator. They are planning on placing an electric motor to propel the elevator car that the people and/or cargo will ride up the ribbon and into orbit. The electric motor is supposedly going to be powered by firing lasers onto a solar panel at the bottom of the elevator car from the off-shore platform. The lasers can be powered by any means, whether using fuels, solar, wind, or whatever. There will be a geosynchronous counter-weight in orbit to keep the ribbon taught. The off-shore platform will be anchored into the sea-bed in a similar manor modern-day suspension bridges are anchored.

I've read about it many times also. And the artwork is awesome too !

But, I don't see how keeping a high strenght ribbon taut, is going to prevent the elevator from twisting in the wind, and keeping the ribbon from twisting, kinking and becoming weakened and unusable. The same would apply with a two ribbon prototype, and even worse with a four ribbon (in each corner of the platform) model. Let alone keep a beam focused on it to power it up and down, while it swings in the wind.

It's a boondoggle scheme, people will invest in only to see if it can be done.

What were these brainstormers before they thought this up, scriptwriters for Roadrunner cartoons?

Beep beep !

The tether would be at least 35,000 km long. The Earth's atmosphere is no more than 100 km thick. There are many technical obstacles, but I doubt if blowing in the wind is one of them.

Carbon nanotubes and ribbons may be improved, I guess, beyond their theoretical maximum strength. I think the way we do this is by alternating left and right winding yarns to form rope. Rope grows stronger under tension, because the yarns are compressed. This is why a steel rope ("cable") is much stronger than a solid steel wire of matching weight.

A nano-built rope need not be perfect in every link, to outperform straight nano-ribbon or tube. Anyway, a little fault is not always catastrophic!

I asked my son (at age 4) about space elevators, explaining the basic principle. He thought that it should be made out of ants. Maybe we need crawling nanobots to keep this in good repair. He also suggested we make the elevator out of magnets. I'm unsure what he had in mind. Is carbon nanotube electrically conductive, or not, or is it optional? What would happen if we ran current through one spiraling lay of carbon rope?

Just wanted to add more to take away confusion, the ribbon won't be pulling the elevator car, the elevator car will be pulling itself up the ribbon.

Of course there will be robotic repair/failure-detection machines, just as there are on large bridges today.

as for blowing in the wind, the counterweight will be placed far enough away and of large enough mass to prevent a catastrophic bend in the cable, though the cable will probably be able to sway slightly just as bridges and buildings do without causing catastrophic failure.

In the case of catastrophic failure, the car will be able to control its descent and land safely.

Gyroscopic sensors in the car could relay changes in position of the solar panels to the lasers which could adjust their position accordingly. Backup power will be available on board the elevator car as well. Under this method, the amount of energy needed might not exceed the amount of energy used in a trans-Atlantic flight.

Fixed ribbon, I can see the car getting stuck between flaws or foreign objects (e.g. ice) on the line, if it has to crawl. Then how do you get down?

Why not run the ribbon as a loop, kinda like an escalator? Then you have one side "going up", the other "going down". And major repair of the entire length possible at either end.

Originally Posted by SuperNatendo

Okay, they want to make carbon nano-tube ribbon, which may be possible in the near future. They are not planning on using rockets as that sort of takes the whole point out of using an elevator. They are planning on placing an electric motor to propel the elevator car that the people and/or cargo will ride up the ribbon and into orbit. The electric motor is supposedly going to be powered by firing lasers onto a solar panel at the bottom of the elevator car from the off-shore platform. The lasers can be powered by any means, whether using fuels, solar, wind, or whatever. There will be a geosynchronous counter-weight in orbit to keep the ribbon taught. The off-shore platform will be anchored into the sea-bed in a similar manor modern-day suspension bridges are anchored.

Are you just repeating what you've read, or have you given this some thought?

How do they get a geosynchronous satellite anchor point into orbit in the first place? Not a nano-tube cannon!

Why is this called a counter-weight?

How in the heck, will a nano-tube remain rigid it's own weight and cross section will affect its free end on the way up.
I know, these guys were sitting around late one night at the local airport hotel cocktail lounge, sticking cocktail straws end to end, and the first one to reach the ceiling got to take Betty the bartender to the penthouse on the elevator. And they got this idea !
Bravo Boys! the drinks are on me ! Unless it's just a Frat prank, then buy your own brew-ski's

Who said, the wind will not affect the nano-tube ribbon?

Are these thinkers all landlubbers, and the wind will never blow, have they considered the Beaufort scale, even a kite will fly in a light breeze. And the string better be really strong in a 13 to 15 mph. breeze.
But then nano-tube cable or ribbon will slice right through the wind!

The fact remains, that any elevator with a payload for space, will have mass and weight, with a cross section at any time while going up or down and the satellite anchor will automaticaly adjust its position with rockets/engines in any direction North, South, East, and West, also in tension with the sea anchor.
And this will have no effect on the strength of super nano-tube in compression of its own weight and payload weight. Plus the strength in torsion against any known force. Including induced frequency vibrations, from drive motors, wind, solar-wind and flares, (above the Earths atmosphere) and flying space objects.

Like I said in an earlier reply, the money required for this idea, would be better spent on newer engines and space/air craft. And Moon bases, robotics and stations between Earth and the Moon. And keep the Hubble in position.

I also think, we should be solving ways of construction and metal forming in space, like designing a machine to form box beams in space, (like a roof gutter machine) and or trusses, geodesic domes/structures.

This whole scheme, sounds fishy to me, like a Spring Brake, Science Guy's Gone Wild DVD !

Originally Posted by Pong

Fixed ribbon, I can see the car getting stuck between flaws or foreign objects (e.g. ice) on the line, if it has to crawl. Then how do you get down?

Why not run the ribbon as a loop, kinda like an escalator? Then you have one side "going up", the other "going down". And major repair of the entire length possible at either end.

You don't want the cable to move for many reasons. One reason is that the cable may actually require an angle until a certain height. Another is the cables may have to be wider in some points than at others. Ace for the ice, that is what the robotic maintenance machines are for. If the elevator car can climb the rope, it can descend just as easily if not easier!! All you have to do is get up, the elevator could use rollers to climb up the rope. to get down, you just use a controlled descent.

It's not about not having to design better space or aircraft, its about spending less money getting the spacecraft away from earth's hold on it.

the counterweight could be built in space just as the ISS has been using traditional rockets.

As for where I get my info, there are many many sources. I first learned of the Idea in a Science Fiction novel, I later read about it in magazines. I also saw the Discovery channel episodes where they were mentioned. Also, there is a large amount of info on Wikipedia. I am just putting forward the most logical ideas at least as far as my opinion is concerned but there are many different ideas surrounding such an engineering feat.

@OldSage. I just wanna clarify no segment of the nanotube is under compression - it's in tension all the way up.


@Supernatendo. A conveyor loop is so much better though if we can pull it off.

It sets up better. Because you can start with a small strand and then wind on additional lays until you've got a working thickness.

It repairs better, for obvious reasons. We can talk about crawling nano repair bots when we're 80. Though ground repair must always be more thorough and efficient.

It even dismantles better.

The climber needn't drive up and down the nanotube, which is going to wear it you can be sure. Imagine what will happen if a bit of dust gets pinched between the wheels and the ribbon... how could we prevent this from ever happening? A motorized climber is so much irrelevant weight too. Better just ...duct tape... your parcel directly to the ribbon. Gah, does the world really need another "car"?!

A loop could carry a continuous stream of lightweight payloads up, and down at the same time. No waiting for the one car to ascend, then descend... at snail's pace too lest this wheeled vehicle damage the ribbon. Or a loop could carry one big container equal to the car weight but I personally like distributing the load to keep stresses consistent.

I don't believe the taper will be necessary, because everything I've read about nanotube & ribbon tensile talks of single walled or multiwalled (laminated) varieties but never wound or woven, never rope. Actually it is referred to sometimes as "rope" by those "landlubbers" Oldsage spoke of... they say "rope" for a uniform tube with walls one atom thick. When we do lay it into proper rope the strength will be significantly greater than the plain straight material, I'm almost certain.

BTW it was quite recently that someone got the idea to make rope out of fibreglass strands, and it turns out that a given thickness is stronger than steel cable, lighter than steel cable, and it doesn't corrode!

Originally Posted by OldSage

Are you just repeating what you've read, or have you given this some thought?

How do they get a geosynchronous satellite anchor point into orbit in the first place? Not a nano-tube cannon!

You either tow an asteroid into position or launch the mass for the anchor from the earth or moon.

Why is this called a counter-weight?

Because its only purpose is to act as a counter-balance for the mass of the cable. So counter-weight seems like a good dscription.

How in the heck, will a nano-tube remain rigid it's own weight and cross section will affect its free end on the way up.

Usually the cable is dropped down from orbit, rather than "raised up" from the ground. Most of the cable is just hanging. That's why it need to have a very high tensile strength - it needs to support its own weight.

I know, these guys were sitting around late one night at the local airport hotel cocktail lounge, sticking cocktail straws end to end, and the first one to reach the ceiling got to take Betty the bartender to the penthouse on the elevator. And they got this idea !
Bravo Boys! the drinks are on me ! Unless it's just a Frat prank, then buy your own brew-ski's

No, actually this was all thought up by serious physicists and engineers.

Who said, the wind will not affect the nano-tube ribbon?

Anyone who did the math? The cable is at least 35k km long. Only 100 km of that is even in the atmosphere. You can calculate the force that wind could exert on the cable and see how much it disrupts the elevator. Well, you probably can't, but other people can.

http://www.mill-creek-systems.com/Hi...chapter10.html

Thank you scifor, that saved me the effort.

Originally Posted by Scifor Refugee

Originally Posted by OldSage

How do they get a geosynchronous satellite anchor point into orbit in the first place? Not a nano-tube cannon!

You either tow an asteroid into position or launch the mass for the anchor from the earth or moon.

A possible counterweight is the cable itself, just longer.

Originally Posted by Ophiolite

Thank you scifor, that saved me the effort.

No problem. That sort of "I'll immediatly conclude that it's dumb without doing any real research because I don't understand it/my gut feeling says so" thing really annoys the hell out of me. Yes, space elevators are somewhat counter-intuitive. Yes, anyone can probably think of lots of possible problems with 2 minutes of thought. But when a lot of serious scientists and engineers have put a lot of thought into the idea and concluded that it's feasible, only an arrogant idiot would think that he can immediately spot problems that the professionals didn't notice after years of careful analysis.

When a lot of educated people who know more about the subject than you have an opinion that seems strange or outlandish to you, the obvious conclusion is that the professionals know something you don't that causes them to have a different opinion. At least make an effort to find out what they might know that you don't before you go around making pompous pronouncements about ideas being crap.

Originally Posted by Pong

A possible counterweight is the cable itself, just longer.

I think it depends on how much mass you want to lift. You have to keep the system's center of mass near geostationary orbit for it to be stable. As I recall most proposals for carbon nanotube cables involve cables that mass in the hundreds of tons. If you have a 300 ton cable you probably can't lift payloads that weigh many hundreds of tons without moving the center of mass too much unless you have a really, really massive counterweight at the top. If you only want to lift a few tens of tons, you could probably get away with a much less massive counterweight. Although you might be able to lift heavy masses without disrupting the cable if you jettisoned the mass off the top of the cable or something.

Originally Posted by Scifor Refugee

Originally Posted by Ophiolite

Thank you scifor, that saved me the effort.

No problem. That sort of "I'll immediatly conclude that it's dumb without doing any real research because I don't understand it/my gut feeling says so" thing really annoys the hell out of me. Yes, space elevators are somewhat counter-intuitive. Yes, anyone can probably think of lots of possible problems with 2 minutes of thought. But when a lot of serious scientists and engineers have put a lot of thought into the idea and concluded that it's feasible, only an arrogant idiot would think that he can immediately spot problems that the professionals didn't notice after years of careful analysis.

When a lot of educated people who know more about the subject than you have an opinion that seems strange or outlandish to you, the obvious conclusion is that the professionals know something you don't that causes them to have a different opinion. At least make an effort to find out what they might know that you don't before you go around making pompous pronouncements about ideas being crap.

Yeah! But its us arrogant idiots, that send you to College in the first place. The first ones you run to when you need Funds.

Many very serious scientists and engineers, spend years in R&D, and spend their entire fortunes while doing so.

Only to be beaten from their goal, by wiser colleagues and R&D teams, with a better idea, and greater funding from arrogant benefactors also.

Don't bite the hand that feeds you!

And remember someone first thought of the screw, before the first nut was made!

And Oh Yeah! It's OK to fail, after your dead and gone, someone in the future, may use your idea, and might even give you credit for it.

Originally Posted by Scifor Refugee

You have to keep the system's center of mass near geostationary orbit for it to be stable.

That's another reason to distribute loading on a continuous loop. A likely elevator design would actually be unstable if it weren't loaded.

Originally Posted by Pong

That's another reason to distribute loading on a continuous loop. A likely elevator design would actually be unstable if it weren't loaded.

I guess it all depends on how expensive the cable is.

Originally Posted by OldSage

Yeah! But its us arrogant idiots, that send you to College in the first place.

I paid for college myself, thanks.

Originally Posted by OldSage"

Many very serious scientists and engineers, spend years in R&D, and spend their entire fortunes while doing so.

Only to be beaten from their goal, by wiser colleagues and R&D teams, with a better idea, and greater funding from arrogant benefactors also.

Don't bite the hand that feeds you!

And remember someone first thought of the screw, before the first nut was made!

And Oh Yeah! It's OK to fail, after your dead and gone, someone in the future, may use your idea, and might even give you credit for it.

I have no idea what any of this is supposed to be about.

OldSage, you are new here. (Welcome by the way.) Take a deep breath and calm down.

Scifor has correctly pointed out that many posters criticise an idea without having understood how well researched the idea is. Your criticisms appeared to be based upon just such an ignorance of the space elevator concept. There are real objections that could be made about the practicality of the device, but these are not the ones you raised.

Further debate on the pros and cons of the elevator could be interesting, but you would need to attack it with solid reasoning, not an argument from incredulity, which is what you seem to have used.

Let us all return to a discussion of the topic, rather than exchanges about arrogance.

Ionoshpere + charge, Earth - charge. Tesla knew this, lightning proves this. How can the elevator rope cope with that kind of discharge and how will discharging the entire ionosphere affect the atmosphere, should the tether survive ?
Bouncing short wave radio would be a thing of the past.
Internal reflection of energy diminished - global cooling ?
The atmospheric standing wave set up by lightning discharge that happens to oscillate at the same frequencies as all mammalian alpha brain waves would cease.
http://www.earthbreathing.co.uk/sr.htm

Originally Posted by Max Time Taken

Ionoshpere + charge,

Are you sure this is right? Isn't the ionosphere essentially electrically neutral since there are equal numbers of electrons and positive ions?

Earth - charge. Tesla knew this, lightning proves this.

Yes, Earth has a slight negative charge, but lightning comes from clouds, not from the ionosphere, so how does this prove anything about the ionosphere? Occasionally lightning does goes upwards from clouds into the ionosphere. Is this what you have in mind?

NEVER happen-only my opinion-materials don't exisit, atmosphere too unstable, rockets cheaper. hazzard to orbiting vheicles . on and on

Originally Posted by fizzlooney

materials don't exist

Well, carbon nanotubes existed last time I checked- that is what the elevator would be made from seeing as it's one of the strongest, yet relatively lightweight, materials we know of.

Originally Posted by fizzlooney

rockets cheaper

Yes, in the short term, however- if a space elevator was constructed (well-constructed!) then it would be far cheaper in the long term. Plus rocket fuel isn't cheap these days either...

Originally Posted by fizzlooney

NEVER happen-only my opinion-materials don't exisit, atmosphere too unstable, rockets cheaper. hazzard to orbiting vheicles . on and on

And this opinion is based on what, exactly? Your experience/education in high-tensile-strength materials and atmospheric modeling?

41 years experence in the missile industry- materials science-
you asked for an Opioion-you got one
People that ask for an opinion and then want to argue abuot it bug the shit out of me.
BYE have a nice day

Originally Posted by fizzlooney

41 years experence in the missile industry- materials science-
you asked for an Opioion-you got one

Somewhere I missed where scifor asked for an opinion. Indeed he was berating people who provided opinions that offered little in the way of substantiation.

It seems you miraculously expected your readers to:
a) be aware of your extensive engineering experience
b) accept that the experience was 41 years worth and not 1 year, 41 times.
c) Drop all scientific scepticism and fall prey to the Argument from Authority fallacy

and when scifor didn't you got pissed off!

Thank you for helping me develop a better understanding of you.

Those little communicatons/tv satellites that orbit the earth in geostationary orbits constantly use fuel to adjust their positions to remain wthin a certain 'space' (100KM cube boxes if I remember correctly). This is due to minor gravitaional changes caused by such things the relative posistions of moon sun and earth, distance of the earth from the sun (as earth's orbit is slightly eliptical), the planets, the solar wind uncle tom cobbly and all. Just before the fuel runs out, the satellite is parked in an orbit outside the geo-stat band. You would need something a lot larger than one of these as the destination of a 'space elevator' and it would need constant supplies of fuel to adjust it's position. The 'weight' of the anchor chain would represent a 'dead weight' pulling on your station, thus trying to pull it down. I have heard of 'capturing' an asteroid and using that, well, newton can tell you how much fuel you would need to use one of those, all the thousands of construction flights etc - these would probably need more fuel than could ever be saved. I don't rule out, I don't say it is impossible, but my money would be on some form of propulsion being found that would make a tethered station obsolete or at least uneconomic, if man can avoid self destruction or global warming or both. If you want it developed/explored in your life time just tell the US army they could drop bombs from a single elevator to any point on earth by releasing them from the elevator as it rises!.

LAST SENTENCE OF OPs QUESTION-"What do you guys think?

Originally Posted by Bunbury

Originally Posted by Max Time Taken

Ionoshpere + charge,

Are you sure this is right? Isn't the ionosphere essentially electrically neutral since there are equal numbers of electrons and positive ions?

Earth - charge. Tesla knew this, lightning proves this.

Yes, Earth has a slight negative charge, but lightning comes from clouds, not from the ionosphere, so how does this prove anything about the ionosphere? Occasionally lightning does goes upwards from clouds into the ionosphere. Is this what you have in mind?

I take it you didn't look at the earth breathing link I posted.

Can the cable handle say 12GW ? And what of the ground station ? A large cumulonimbus carries more than 4 lighting strikes worth of energy.

Wouldn't it be simpler to make a spacecraft that can glide and use powered flight in the atmosphere, Hollow out Everest(6Km of tunnel), put an elevator in it and do fly by pick-ups from there ?
Miniature fission fusion hybrid for power on craft ?

If that sounds expensive check out how much has already been spent on the elevator.
How much more useful and eco friendly would miniature fission fusion hybrids that can be used in air craft fuelled by hydrogen oxygen fuel that simply fill their tanks with salt water ?
Even to power hotels etc etc etc.

Originally Posted by fizzlooney

LAST SENTENCE OF OPs QUESTION-"What do you guys think?

So you acknowledge that scifor was not the one who asked for an opinion. So berating him for asking you about your opinion was simply you being rude. Thanks. I just wanted to get that point clarified.

Originally Posted by Max Time Taken

I take it you didn't look at the earth breathing link I posted.

I glanced at it but seem to have an aversion to reading white-on-black text so didn't get very far with it.

I have read elsewhere (NASA e.g.) that the ionosphere does indeed carry a positive charge so thank you for bringing that to my attention. The potential difference earth to ionosphere is 300,000 volts.

Can the cable handle say 12GW ?

I dunno. Does it have to? 12GW divided by 300,000 volts gives a current of 40,000 amps. Divide 300,000 volts by 40,000 amps and you get a resistance of 7.5 ohms. Is it conceivable that a 30 kM long cable of any material could have a resistance as low as 7.5 ohms? I'm just asking.

Originally Posted by Home200

You would need something a lot larger than one of these as the destination of a 'space elevator' and it would need constant supplies of fuel to adjust it's position.

No, you wouldn't. The physics of the space elevator cause its position to be self-correcting. It has to be, because every time a load travels up or down it, it changes the angular momentum slightly. Fortunately, it corrects itself automatically without the need or engines etc. The energy needed to do this comes from the earth's rotational energy. It does not behave the same as a satellite trying to stay in a certain spot in orbit.

Originally Posted by fizzlooney

you asked for an Opioion-you got one
People that ask for an opinion and then want to argue abuot it bug the shit out of me.
BYE have a nice day

No, I never asked you for your opinion. Some guy named shawngoldw asked for it (well over four years ago). I asked if you had any experience with high-tensile strength materials or atmospheric modeling. And now, I must add reading comprehension to the list...

Originally Posted by Scifor Refugee

And now, I must add reading comprehension to the list...

I had already added being polite, so he's getting quite a list.

Originally Posted by Anonymous

In 1936 they said by the 1960's we'd all be in flying cars.
1n 1976 they said by the year 2000 we would all have domestic robots doing all the chores.

In 2006 they said we'd have a space elevator within 50 years...

Well I'm now beginning to create my suicide note..

Your comment discuss me, I found my self in a state of awe and grossed of the idea of a someone capable of accessing a world data base filled with every single bit of information gathered through out human existence and one of those contributors is saying

Originally Posted by Anonymous

In 1936 they said by the 1960's we'd all be in flying cars.
1n 1976 they said by the year 2000 we would all have domestic robots doing all the chores.

In 2006 they said we'd have a space elevator within 50 years...

How simple minded, horrifically limited, contained can you, WE! be.
I know the future, we will split. form two human governments ONE full of cultured domesticated mindless entity's, the other throwing away everything that is what you define as "human" becoming purely calculated conscious entity's with one goal that is to survive...
There will be trillions of us by 2100.

Just try and grasp that information and apply it to your comment.

If we were having this conversation face to face oh what I would do...

How did his comment discuss you? I thought it discussed the idea you posted.

Perhaps he meant "disgusted"? That would fit in with tenor of remaining post. Just a supposition.