Space Elevator - Won't Happen

Mass producing carbon nanotubes. From: www.nanonordic.com...

We say that we’re at R&D phase II, as the equipment that we’ve built is more of a pilot plant than an actual piece of lab-equipment. If we work 24/7 we’re able to produce 50 gram/day. But we only run the equipment approx 6-8 hours a day as our primary goal is to investigate the parameters to look closer at production rate and quality. Our plan is to have a process-book available very soon. We want to move from 20KW to 100KW which would enable us to produce several kilograms daily. For mass-production and industrial applications yet more time is needed and it is plausible that we will arrive there around 2008, Bruno says and adds:

– However we’ve already started pre-commercial production and we’re selling small quantities already

Seems like this is going to be big business, the link says that nanotubes currently are quite expensive with prices ranging $100-$500 per gram. Don't know how reasonable there projections are, mass-production by 2008, but seems like its gonna happen. Big money in this stuff, no?

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Here is Brad Edwards
President of Carbon Designs Inc.
Dallas, Texas
Talking about various aspects,
He addresses wind, lightning, as well as other aspects of it.
www.sciencefriday.com...
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I don't know if someone has mentioned this before but in the last sequel to 2001, A Space Odyssey, Aurthur.C. Clarke describes a "space elevator".

The structure is one of four at equal distances around the equator. South America, Africa, Asia, and the Pacific. They are all connected at high altitude thus eleviating many of the stresses caused by the Earth spinning on it's axis and providing a high speed transport link across the globe.

I'd like to think it was possible but I can't see how only one could be built without the support of atleast three others similtaneously connected at stages. Otherwise it would bend against the rotation of the Earth in quite a marked way.

I've worked with high tech Carbon and yes it is strong but it is not indestructable and can be prone to stress fractures caused by repeated bending back and forth.

At that altitude the strength needed is not as in a sky scraper. The higher the structure the the more marked the effects of gravity on it.

Let me try to explain. At sea level around the equator the effect is as we all recognise but effectively the higher you go the greater the circumference of the rotation. A point at the tip of a building 20 miles high will travel further within the 24 hour period than a point at sea level.

Greater Distance of Circle + Same Time Period of Full Rotation = Increased Gravitational Effect. (Spin Appears Faster)

Unless, of course, multiple towers support each other.

One tower at the either pole would not have the same stresses. More twist stresses instead. And the axis of spin isn't constant. It wobbles through a small circle through a year.

I don't know if that adds anything to the debate.

[edit on 7-6-2005 by John bull 1]

John bull 1, you are right about alot of things.

Even the about the stresses that will be exerted upon the cable, you go into more details then I have. But it think that they would accelerate the orbiting counterbalance to match up with the rotation of the earth. This is my biggest problem with the project, and I'm going to defend it until I see this thing up and running or until some one gives me the math and proves me otherwise.

Carbon nanotubes are prone to stress fractures. But the ribbon is not all carbon, it has an epoxy to make it flexable to reduce the risks of this happening.




[edit on 6/7/2005 by GoldEagle]

I just wrote a relatively short thesis/research paper about the space elevator, and I intend to convert it to html format and upload it for everyone to tear apart or support if they so desire. I just want to flesh out a few parts because the actual paper had a length restriction (that I went over) and go to prom.

My views come across very clearly in the paper.

A geostationary satellite from the ground observer would appear to hover in the same place, because its circling the earth at the same speed of the earths rotation, so it appears to never leave its spot. the elevator would be much the same.

It would be 62,000 miles long, and at the end would be a counter balance, even if the the cable from top to bottom isn't perfectly straight up, it doesn't matter because the cable is flexable and not rigid like a building.

OK, the idea is really neat, and the technology is all fanciful and intriguing, but c'mon, really.

I see a couple of posts talking about the primary objectives that need to be overcome, and nobody is gonna mention the most obvious? Security.

How are you going to guard a space elevator tether against terrorism? All 62,000 miles of it? And what happens if something catastrophic happens and all 62,000 miles of it come crashing down to Earth?

This is a simple, practical concern that will be unbelievably daunting to say the least, not to mention the even more complicated technological issues. I've seen so many different versions of this idea now, that everytime I see another version, I can't help but think of those old black & white propaganda films that showed people living in houses shaped like bubbles. Then they'd come out of their house, and climb into a jet-powered car with folding wings. They were pretty sure our world would be just like that, but it didn't turn out that way.

Originally posted by AlphaMail
How are you going to guard a space elevator tether against terrorism? All 62,000 miles of it? And what happens if something catastrophic happens and all 62,000 miles of it come crashing down to Earth?

- before you go spounting off on how it cant be done, how about you learn about it first...With this post I quoted from you its obvious you havn't even read other peoples previous posts.

and of course security will be the biggest things...and when its all said and done some of the security measures wont be public knowledge, and for good reason.
However some is revealed, like: It will have a large no fly-zone, and its location doesn't interfere with any routes, there will be patrol boats, and its highly probable that it will be gaurded by the US military, as for that cable itself...when the cable is 'deployed'/'unraveled' it wont be complete, they will use the 'climbers' to finish it.....Then once they have one cable successfully built they will use there first cable to build another one, making the cost of building another one greatly cheaper, They are currently thinking of around 4 of them. So if the missile actually hits the cable, and actualy destroys it, they still have 3 more, and still have the 4th ones ground base, which they will re-use to re-build the 4th one.

I want to address the heat problem with the elevator. The sun hitting the ribbon can generate large abounts of heat. I remember from a building that was getting worked on that the concept of "solar loading" can generate tremendous amounts of heat on the walls of a buildings. In one case I can recall that tempratures exceeded 100 Celsius. This cable will be constantly exposed to large amounts of solar radiation, more than here on earth which generates heat. This on 60000 + km of ribbon can cause large amount of expansion and contraction which can de-nature the carbon nanotubes.

As a vauge example, sort of how glass is prone to stress fractures, from applied forces, expansion, and contraction.

Nanotubes are very resilient to temperature fluctuations, which is why they have been considered for laser weapondry protection. Inaddition it is well known that nanotubes have the worlds highest torsion/tension/compression/expansion factors. I don't think it will be a problem in a future space elevator.

[edit on 12-6-2005 by Sigma]

Originally posted by Sigma
Nanotubes are very resilient to temperature fluctuations, which is why they have been considered for laser weapondry protection. Inaddition it is well known that nanotubes have the worlds highest torsion/tension/compression/expansion factors. I don't think it will be a problem in a future space elevator.

[edit on 12-6-2005 by Sigma]

I don't know about it's torsion/tension/compression/expansion characteristics, I wan't to get some numbers. Can you get us a link of the properties of carbon nanotubes that you got your information from?

Thanks.



[edit on 6/15/2005 by GoldEagle]