Space Elevator - Won't Happen

Okay, seriously people. The space elevator is not going to happen the way they say it will. There are many reasons why.

Too Heavy (not in space, but the trip up there)
Carbon Nanotubes are difficult to make with the current tech. we are at
High altitude consturction, hard and dangerous
Company involved does not have a clue of what they are doing
Not normal structual stresses here on Earth, in space its a whole new ball game.


This thread will releases the pressure on the Ion Thruster thread.


[edit on 6/1/2005 by GoldEagle]

Space Elevator will happen... ok it might happen. There are alot of things that need to come together before it is even considered a possibility. The biggest hurdle has already been jumped, that being the material with the structural capability to support such an endeavor, carbon nanotubes. Now the problem lies in creating the proper alignment and creating enough of them. The other factors, if considered, are quite negligible and require the use of present industry to accomplish, except, perhaps for the lifting device, which will need to be programmed and be in itself a moving assembly line, from what I gleaned of their ideas.

The benefits outweigh any of the negative aspects IMO. Sure it will be a lot of work, but when it is finished space will be opened like it has never been before.

[edit on 1-6-2005 by Sigma]

You know there is a distinct difference in being Skeptical and being a SuperSkeptic. The main difference is that Skeptics do their homework which you have not done as all the issues you have names save for the CNT problem have been resolved already. As for saying the company doesn't know what its doing well thats just stupid as no one really knows what they are doing with this technology, that is what science is doing things that no one has done before.

The Construction will NOT be done by humans Period. That is not a consideration. Carbon Nanotubes in case you didn't know are 1/6th the weight and 100 times strong then steel so the Weight issue is not an Issue.

The Primary Factors are as such:

1. Cost - Can be dealt with when CNT's become a commodity which is expected to happen within the next 10 years

2. Environmental - Just what effect will such a structure will have on the environment noone knows

3. Tearing - CNT's are prone to tear when strained. This is by far the largest hurdle according to Physists I have personally spoken too

As always things of this nature will seem impossible to the uneducated as was Skyscrapers and Heavier then Air flight but as you know they are now common-place.

EDIT: One other question, Just what is your education in the field of Physics? Highschool? College? University? I find it very hard to take you serously in this issue, as most the issues you name have already been dealt with.

en.wikipedia.org...
The cable must be made of a material with an extremely high tensile strength/density ratio (the limit to which a material can be stretched without irreversibly deforming divided by its density). A space elevator can be made relatively economically if a cable with a density similar to graphite, with a tensile strength of ~65–120 GPa can be produced in bulk at a reasonable price.

By comparison, most steel has a tensile strength of under 1 GPa, and the strongest steels no more than 5 GPa, but steel is heavy. The much lighter material Kevlar has a tensile strength of 2.6–4.1 GPa, while quartz fiber can reach upwards of 20 GPa; the tensile strength of diamond filaments would theoretically be minimally higher.

Carbon nanotubes have exceeded all other materials and appear to have a theoretical tensile strength and density that is well within the desired range for space elevator structures, but the technology to manufacture bulk quantities and fabricate them into a cable has not yet been developed. While theoretically carbon nanotubes can have tensile strengths beyond 120 GPa, in practice the highest tensile strength ever observed in a single-walled tube is 63 GPa, and such tubes averaged breaking between 30 and 50 GPa. Even the strongest fiber made of nanotubes is likely to have notably less strength than its components. Further research on purity and different types of nanotubes will hopefully improve this number.

[edit on 1-6-2005 by sardion2000]

Sardion,
Rather than putting down the Gold Eagle with a personal jab, you might want to consider some of the other tech balloons we've been sold for the past 20 years, say, fusion power, superconductivity, and, oh yes, cheap access to space via a somewhat reusable shuttle. They are all going to happen. Next year. Maybe in 5 years. Someday. For sure.

The space elevator is a cool concept, but even it's proponents realize there are massive hurtles to overcome. Simply dismissing the whole issue of the environmental impact by saying no one knows is silly. The last elevator conference at Los Alamos conducted a session on the topic and there are indeed serious safety problems that CNT 's pose.

Originally posted by sardion2000
You know there is a distinct difference in being Skeptical and being a SuperSkeptic. The main difference is that Skeptics do their homework which you have not done as all the issues you have names save for the CNT problem have been resolved already. As for saying the company doesn't know what its doing well thats just stupid as no one really knows what they are doing with this technology, that is what science is doing things that no one has done before.

The Construction will NOT be done by humans Period. That is not a consideration. Carbon Nanotubes in case you didn't know are 1/6th the weight and 100 times strong then steel so the Weight issue is not an Issue.

The Primary Factors are as such:

1. Cost - Can be dealt with when CNT's become a commodity which is expected to happen within the next 10 years

2. Environmental - Just what effect will such a structure will have on the environment noone knows

3. Tearing - CNT's are prone to tear when strained. This is by far the largest hurdle according to Physists I have personally spoken too

As always things of this nature will seem impossible to the uneducated as was Skyscrapers and Heavier then Air flight but as you know they are now common-place.

EDIT: One other question, Just what is your education in the field of Physics? Highschool? College? University? I find it very hard to take you serously in this issue, as most the issues you name have already been dealt with.



[edit on 1-6-2005 by Realist05]

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Firstly a cable has to support its own weight.

A steel cable hanging down will break under its own weight at around a few hundred miles.

As you get very far from earth the gravity does gradually become reduced, but the cable has to hold all the cummulative weight how ever far it hangs. These nanotube cables will have to be near perfect.

Now add the car's weight.
Now consider wind/weather/tectonic-shift stresses.
As someone has mentioned the cables wear.
Imagine the repercussions if a 10,000 mile long cable snaps, don't want to be standing anywhere close to where it hits, and recoils and hits and recoils. edit: maybe your could have auto release connectors if the cable breaks.

I thought of a circle of slightly smaller cables [all around the car]. That way you could replace one without stopping service. The car itself could pull out a single new cable as the other end was wowned up, using the remaining cables to run on.

I am guessing it would be impractical to have the car be pulled up on a central cable [like an elevator, too much cable] so i think it would have to crawl up the cables using some kind of clamping friction grip wheel pairs. How much fuel would that take? A large part of the initial weight would be the car fuel. The trip down could be powered by gravity and braking friction.

Also there is a small amount of inertial velocity that is lost each time some mass is move up the cable, so you would have to [from time to time] add a bit of velocity to the orbiting platform/planetoid. If you moved about the same amount of mass down the cable this could be equalized. maybe you could have two cable sets with one car going up while the other went down. I wonder if there might some ability to use the freefall energy of the down car to give some lift to the up car?
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[edit on 1-6-2005 by slank]

whoa there slank, Your talking about a normal elevator...which this isn't the "cable" is actually a riddon, a few feet wide and paper thin. It would pull itself up.

look...i'm kinda getting tired of repeating myself on this matter.

THIS IS TO EVERYONE
Learn at least a little about the topic before you add your 2 cents.....thanks.

The big key is producing the nanotubes the correct size. Most likely that 'factory' would be shipped to an orbiting space state and the cable would be dropped from orbit to a ocean based platform. ONce that is done you can start "spinning" the cable to strengthen it, like you would for a susupension bridge.

THeortically possible, yet impraticle at this point becauseof the lack of matrials and money.

a counterweight would be used to left and lower people on the elevator a low level of accelertion similar to what you would find in elevators if sine if the tallesy sky scrapers.

Most of the contruction ideas I have heard about uses robots and not humans to do most of the menial work

can you find a company that does know what it is doing when it comes to making space elevators?

THere is actaulyl very little stress invovled and most could be taken care of by giving the cable a slight, controlled wobble

we will see in the next 20 years how far they can go. The big pay off is cheap and energy efficiant way to get into orbit and off thise Forsaken rock

I learned the topic. I know what it's about.

slank your right, but a bit off. The cable is not supporting it's wieght. It is rather being swung into place by a counterweight, just like if you put a weight at an end of a rope and spun around. The forces are responsible for keeping it strait and tought. This method of keeping it up is well thought of. The only problem is that the stresses are going to be enormous and thats my biggest problem with the idea. Who knows, in 20 years we might be able to maintain those forces, but the idea is sci-fi by todays standards.

I still don't think it's going to happen. Mabey not in 20 years, but in a long time.

Note: Nice how you call people like me uneducated. That's one of the greatest personal insults to me, becuase I didn't just blow $75000 on pencils, textbooks, paper, pizza, and calculators. Thanks for the comment! Thanks for bashing me up like that, I mearly am providing another side of this debate. You can't seem to understand that can you? This space elevator is a life or death thing for you it appears, then fine, but for me it's another think that needs to be worked out. Just because people don't think like you, It doesn't mean were uneduacted.

[edit on 6/2/2005 by GoldEagle]

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Whether it is the tension out or gravity down it is still the tension break point/energy that has to be considered. The weight of the cable still has to be factored in up to the point that gravity becomes zero. All those atoms of carbon are still being pulled to the gravitational center of the Earth. Also the additional tension pulling out has to be added to gravity. This will have to be one 'H' of a cable(s).

A ribbon would be much more subject to wind problems.
With something that thin and long a ribbon would likely be wracked by the wind.

A round cable is essentially as streamlined [from all directions on a plane] as is possible so would have as minimal wind problems as possible. But a cable holding the tension of its own weight and the orbiting planetoid/station has to additionally stand wind and weather stresses and the weight of a car.

ground tower?
You could build a structure upwards for some number of miles [50, 100?] to elliminate some of the length/gravity stress on the cable, but I doubt that would be a significant factor. [but since that is where gravity is strongest it might make some difference]. Any tower though also has to withstand its own wind problems, as is common with tall buildings.

What about a partial elevator?
Where you took a flight up to a car that hung down from some orbiting [at freefall] platform? Then rode the car the rest of the way up? Probably wouldn't work but anyone see problems or advantages with that?

A partial elevator might elliminate a big portion of the cable weight, where gravity is strongest. The cable [& orbiting platform] would probably be moving with respect to the planet, so the plane would have to syncronize the same speed with it for transfering passengers and cargo.
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The stresses are so enormous that the ribbon will hardly move around in the wind at all.

I couldn't find it, but what is the mass of the "planetoid" that this thing is attached too? It would need alot of mass to keep that large cable, err... ribbon tought. The tensile force would exceed 160GPa. I think that ribbon should be a bit thicker instead of paper thin.

Remember in space you are wieghtless, but not massless. If things were massless you would be able to stop the space shuttle with one hand in space.

Originally posted by sardion2000
3. Tearing - CNT's are prone to tear when strained. This is by far the largest hurdle according to Physists I have personally spoken too

sardion2000 who are these physicist you are talking to? I live in Toronto too, If they are at a university I want to meet with them sometime.


[edit on 6/2/2005 by GoldEagle]

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With something even yards across but thousands of miles wide with only a small amount of flexion of each atom the ribbon would be able to twist and wind all around.

You might have to build in shock absorbers in the cable to keep it from breaking as the earth shifts around.
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slank - we cant build a 50 mile high building...thats crazy. If you use steel it will collapse under its own weight at just 2 miles.

and the concept you referred to exist, where you have a hook around 150km up, and a space plane uses a rocket to get there and hooks the payload on to it.

However then you also need to build a space plane.

But that idea has become less popular over the last few years, because the people that though it up relized that carbon nanotubes were very strong. In fact the President of LiftPort says they are 3 to 5 times more powerful then they need to building the space elevator.

and shock absorbers??? it will be built on a floating movable oil-rig-like platform, and will be built where hurricanes are rare, and good weather is often.

Murcielago you did a good job in ironing out the ribbon problems, but can you help me out here a bit. How will the "cars" function and what are the specs on them? Will the be like the Mag-Lev or have wheels the "drive" up the cable?

Another thing that got me down about this space elevator thing is that I belived it was a figment of Richard Hoagland's bizzare imagination. He uses it to explain that damn Iapetus crap. You all know how much I get along with him.

[edit on 6/2/2005 by GoldEagle]

Gold Eagle
I couldn't find it, but what is the mass of the "planetoid" that this thing is attached too? It would need alot of mass to keep that large cable, err... ribbon tought. The tensile force would exceed 160GPa. I think that ribbon should be a bit thicker instead of paper thin.

It proably will be thicker then a sheet of paper, I type that so it sets in in peoples minds that its not your typical round cable. However it will still be very thin.

earlier version suggested a large planetoid counter balance, like an asteroid. But now they relize they dont need something that large, in fact the weight at the end of the cable of all there equiptment and what not will be enough.

Originally posted by Murcielago

Gold Eagle
I couldn't find it, but what is the mass of the "planetoid" that this thing is attached too? It would need alot of mass to keep that large cable, err... ribbon tought. The tensile force would exceed 160GPa. I think that ribbon should be a bit thicker instead of paper thin.

It proably will be thicker then a sheet of paper, I type that so it sets in in peoples minds that its not your typical round cable. However it will still be very thin.

earlier version suggested a large planetoid counter balance, like an asteroid. But now they relize they dont need something that large, in fact the weight at the end of the cable of all there equiptment and what not will be enough.

Okay, I see what you ment. I know round cables would be difficult to work with. The asteriod thing would not have worked well... becuase where are they going to get an asteroid, and move it into orbit.

I hope this elevator thing will work but in the back of my mind there are burning questions and a feeling I can't get rid of, that leads to it not happening soon, but it may in the distant future. I think it's politics and money are the big problems for me - Richard Hoagland's tripe, I strongly oppose his idea's (not him as a person) and space elevators came up, and I've been trying to prove him wrong ever since.

Work continues in the development of long Single-walled Carbon NanoTube (SCNT) fiber production; espcially at Rice University, and with the suppport of organizations like LiftPort. It is really just a matter of engineering before we can produce CNT's of a meter or so in length in quantities and at low enough cost to make the rquired ribbon a possibility.

Prediction: 2-3yrs to develop a technique to cable of mass prodicing high-quality meter length CNT's, 1-2 more years to weave said fibers into a test cable/ribbon; infrastructure development for first cable with 10-15 yrs of today. 1st Space Elevator operational by 2035.

Now to correct a common mis-conception about space elevator systems: It is NOT centrifugal force pulling the robbon taut, it is gravity pulling the ribbon down from space.

Actually the very term Space Elevator is somewhat misleading; it is actuall more of a Space Bridge, albeit a bridge 22K miles long and, relative to the perspective of us earthbound humans, a bridge that goes up instead of across.

Think of it like this:

Two cars, side by side begin driving around a circle 50FT in diameter. Now the outside car, while staying exactly paralell to the inside car, increases the distance between the two cars by, say 12FT. Now, the passenger in the outside car begins extending a tape measure tape to the driver of the inside car, who clips it to his door. The tape is now a bridge between the two cars.

you can call them cars/climbers/lifters, but whatever you call them there is no set design. there are a variety of looks. But there are some features that stick with virtually every design. and that is: There will be a powerful laser on the ground that will "beam" the power up to the climber, which will likely have solar cells on the bottom of it, to collect the power. then picture the tether, and on each side of it think of a tanks wheels/tracks.

Heres some pictures:











The Future?

You know instead of point out flaws in the space elevator, I would be beinifical to a lot of you skeptics to educate yoursefl on the propsals, and theories withthe contruction and design of the space elevator.

Look thru this and a lot of the ideas are laid out for you to look at
www.isr.us...


One of the Chalalnges discussed is if the Cable breaks. Even a worse case scenario with a break at the Anchor point in orbit most of the elevator would burn up and turn into Nanotube and expoxy dust, with a small segment at the bottom imapcting the ground.

The ideal location this group has proposed for the space elevator is off the coast of ecuador where there is a low occurance of lighting strikes, and no hurricaines. Send it 50 miles off shore and there is very little chance of damage to land based structures.

Regardless a 20 ton capacity cable has less mass then 2 fully fueld TitianVIb rockets which are the current alternative to getting things into space.

For an estimated 40 billion US dollars I don't understand why govenemtns are jumping at the chance to make this a reality

If the cable snaps in the middle (for whatever reason), it will settle back down to earth, because its lightness, it would be how most imagine, which is a steel cable come whiping down from a hurdred miles up, slicing people in two.

ho, and LiftPort says they can build theres for an estimated 10 billion. which for contrast, is 2/3 of Nasa's yearly budget.

I have a friend who has a patent pending for a new method of creating carbon nanotube lattice structures that he says can be used in the construction of the space elevator. He says He can also make filters with this method that will filter a single type of molucule. He can lay the nanotubes to allow only a certain shape of molecule through.