The Space Elevator

[Jonathan]

One would think a person who calls himself Spock would be interested in a space elevator...

[Spock]

...I'm a logical person......and agree with Mork from Ork; "reality, what a concept"

[trolls' bane]

Originally Posted by durinsbane2244

so...a spaceship carries a cable, and pretty much just drops it to earth? what about burning in the atmosphere? what makes it fall with no gravity? what keeps the whole elevator and folks therein from burning?

No burning... It would, of course, be lowered at only a few hundred feet per second. It would take quite a while for it to drop.

And Jonathan:
That would be a pretty difficult target for anythign to hit. A bird would pose no threat. A mircometeorite (or a big one, 'cause in this case the chances of it hitting would be greater), on the other hand might pose a major threat. But the tensile strength of nanotubes is far beyond simply breaking.
But on the other hand, I don't have an answer for your climber question. I guess I'll have to read my new book to find that out.

EDIT: In fact, if I can't answer, refer to Bradley Edward's paper.

[Jonathan]

Originally Posted by trolls' bane

That would be a pretty difficult target for anythign to hit. A bird would pose no threat. A mircometeorite (or a big one, 'cause in this case the chances of it hitting would be greater), on the other hand might pose a major threat.

At ground level? No, I think the chances of a bird hitting would be much greater than a meteorite impact. Because we are talking about a thin string of nanotubes hanging down from the sky, right?

Originally Posted by trolls' bane

But the tensile strength of nanotubes is far beyond simply breaking.

The tensile strength of "a cable a few nanometres wide" (basically a single nanotube molecule) is broken very easily.

You know, a material's ability to break is related to its thickness. The thicker, the stronger. Even though nanotubes are much much stronger than most other materials, you're greatly overestimating its tensile strength if you think the material is "beyond simple breaking" when it's that thin.

[trolls' bane]

*shuts down and goes into "Ask Doctor Edwards not me" mode, to releive the pressure of trying to prove/disprove something*

[Nurvingiel]

A space elvevator eh? While we're up there, let's vacuum all the extra CO2 and crap out of the atmosphere.

Would we really be able to build a space elevator? Where would it go? I mean, no one is going to want an eyesore like that in their back yard. I wonder how far such a tall structure would be visible in a clear day.

Also, would building an elevator to space (presumably to launch space craft much more efficiently) really be the wisest allocatioin of resources? (Not that I'm bitter from living in pre-Olympics Vancouver or anything. )

Who would invest in this project? Who would own it? How would one get "in line" to launch their shuttle?

This idea is intriguing from a human impact and logistics point of view as well as physics.

Speaking of physics, what would the elevator be made out of? How big would the base have to be? What kind of structure would it have? (I'm imagining a giant powerline thing, like this one, but maybe that wouldn't work.

[Jonathan]

No idea about your other questions but I can answer this one at least

Originally Posted by Nurvingiel

Speaking of physics, what would the elevator be made out of?

We've been discussing carbon nanotubes in this thread and that would according to scientists probably be the best material to use.

[Nurvingiel]

Oh yeah, that's a lot of carbon nanotubes! And since they have to be made in a vacuum, I think it would take ages to make enough. What a megaproject eh?

Maybe TB can answer some of my other questions. He knows a lot about the project.

Now I'm extremely curious as to where it would be built. There are so many factors that would have to meet a certain standard. The mineral soil (since they'd definitely remove the top soil) would have to be very solid. Or maybe they'd dig down to bedrock, in which case it would have to be a solid piece of bedrock. Maybe only some types of rock would be acceptable.

The terrain would have to be flat, or made flat. Maybe they would want a high elevation? If you could build it on the peak of Mount Everest, for example, you would have 8000 m less of carbon nanotubes to use. (Obviously that's not where it would go.)

Also, the region would have to have relatively calm weather, I imagine.

Anything I left out there?

[trolls' bane]

1. Yes we can. It won't be an eyesore, because it won't be very visible, even if I'm wrong about the size.

2. Yes. Don't you want 3 billion cubic meters of hydrogen just to yourself? (Yeah, I know, the number is way off, but it was in the low billions.) Don't you want to retire on Miranda or perhaps our recently demoted neighbor, Pluto? Wouldn't you rather empty all these prisons by sending their prisoners to some asteroid to serve their slightly shortened time by mining valuable minerals.

3.

(Will answer later... HAve to eat...)

[Gwaimir Windgem]

Originally Posted by trolls' bane

2. Yes. Don't you want 3 billion cubic meters of hydrogen just to yourself? (Yeah, I know, the number is way off, but it was in the low billions.) Don't you want to retire on Miranda or perhaps our recently demoted neighbor, Pluto? Wouldn't you rather empty all these prisons by sending their prisoners to some asteroid to serve their slightly shortened time by mining valuable minerals.

You sound like a Hutt.

[trolls' bane]

Originally Posted by Gwaimir Windgem

You sound like a Hutt.

No I don't! *tries to hide bulge of fat and squints to make eyes look small*

Anyway, where was I...ah, yes.
3. Currently, a company called LiftPort, using the Edwards design, even has a countdown for the construction. It's a shot in the dark, but at least the target breaths loudly enough. Investors would more than likely be large companies (likely) and governments (ha!).

4. No lines to launch shuttles, because no one would launch shuttles. There would be very little in the way of ships moving up and down the elevator, besides satellites and ship parts. For the most part, ships would be at stations (placed at certain altitudes that would be desireable to shoot directly towards a limited number of planets w/o the slingshot effect, in this case limited to the inner Jovian planets through Mercury) waiting for passengers and cargo.

5. It would be a single cable (as Jonathan said, made out of carbon nanotubes--a type of Fullerine), about 91,000 km long with a counterweight at the end. The opposing gravitational and centripetal forces would keep it straight. (And the carbon nanotubes are strong enough to support twice the weight they need to support for all the cable below and above, according to the text.)

6. Megaproject, yes. (Expensive, yes.) Ages, no. There is quite a bit of research. They're proposing that nanotubes can be made in large assembly lines, though I have to admit that they are some years away.

6b. Thanks. I don't know everything about it, as you can see further up the thread, but I'd like to think I'm familiar with it.

7. The notion of something so large can be misleading. It is most likely not going to be built on land at all. The cable base would be a moble ship that stays within a small area just west of the Galapágos Islands. (The base would resemble a mobile oil rig--in fact, it probably will be a mobile oil rig--more than a ship.) That part of the pacific has a high percentage of cloudless days and no excessive winds (it is, after all, in the Doldrums).
The terrain doesn't necessarily have to be flat, anyway. You could extend the cable from a small cement box on the side of a mountain, but that wouldn't be very practical or useful.