SuperSaiyanGokuX wrote:

Depending on how much of the cable was left on our end, it could have a significantly greater impact than Mir...

Mir fell from outer space, through all of the atmosphere, and mostly burned up...

This cable would likely get extremely hot on its fall, and perhaps the highest end would get melted away, but a large portion of it wouldn't fall through enough atmosphere to disintegrate before hitting Earth...

Since the cable is very thin, it'd probably burn up a lot quicker than other stuff- more surface area and not much substance to provide impacting-ness.

Not sure how far a mile is in kilometres, but for the idea to work, the 'space' end of it needs to be in geostationary orbit, or the cable just gets wrapped around the Earth. You can't just put it further away and speed it up, or it'll break out of orbit. There is only one height for geostationaryness, and that's where it'll be. So if the end broke off, it would just continue orbiting the Earth.

It would, however, have no serious impact if it fell. Imagine dropping a piece of string from the top of the eiffel tower. Nothing much happens. Now drop a piece of string as long as the Eiffel Tower is tall from the top of the Eiffel Tower. Nothing happens. The cable won't be much thicker then string, I think you'll find.

Yeah, I'm sure they won't undergo something like this without planning for the worst... If anything, they'd at least be doing a lot of "potential monetary losses" studies, and figuring out ways to minimize the damage done in a catastrophe...

I'm just saying that this thing really would have the potential to cause a lot of harm should something go terribly wrong... Even with contingency plans...

But again, I'm not trying to use that as an excuse not to go with this idea... I'm all for this project...

Something that just struck me about burning up during the fall, though... If this stuff is as strong as they say it is, wouldn't it also be incredibly heat resistant? Meaning it might not burn away at all? (this has more to do with Elation's reply, rather than Xooxer's)

Jmurph wrote:

Security aside, I would think environmental wear on these would be terrible. And what do you do when a hurricane or storm stirs up near it?

Such headaches....

Not to mention possible terrorist attacks.

`Jx

Jp wrote:

Not sure how far a mile is in kilometres, but for the idea to work, the 'space' end of it needs to be in geostationary orbit, or the cable just gets wrapped around the Earth. You can't just put it further away and speed it up, or it'll break out of orbit. There is only one height for geostationaryness, and that's where it'll be. So if the end broke off, it would just continue orbiting the Earth.

Actually, you can put it out farther than that and it won't leave orbit. The cable holds it into its unnatural orbit.

In fact, if you put it into a geostationary orbit it won't stay up. The friction on the cable will pull on it slightly, forcing the orbit of the satelite to slowly decay. You need the centrifugal force to counteract that. This thing would stay up because of centrifugal force, not centripetal force.

Also, I do believe the plans for the thing that were given to the media claimed the thing would be 60,000 miles.

It would, however, have no serious impact if it fell. Imagine dropping a piece of string from the top of the eiffel tower. Nothing much happens. Now drop a piece of string as long as the Eiffel Tower is tall from the top of the Eiffel Tower. Nothing happens. The cable won't be much thicker then string, I think you'll find.

I think that depends on how much the thing will bend. If it is fairly stiff and only bends slightly, it might fall sideways like a tree, damaging anything it falls on, which will most likely be only those vessels coming to or going from the site out in the ocean. And even then only if it falls directly toward them and they are within 20 miles. Highly unlikely.

If it is as flexible as yarn, it will probably just fall on whatever is directly beneath it. In this case, I would assume people would not be allowed under it unless they are boarding it.

Either way, significant damage is highly unlikely, yes.

As for the thickness of the cable, it is likely to be at least half a foot in diameter, I would think, if not more. It might even be several feet across. A string thick cable would make the whole thing even less believable.

Not all 60,000 miles of it would fall down. As we have said several times elsewhere, only the portion under a break would fall. The rest of it would shoot out into space and either fall into a large orbit or escape to orbit the sun, either case resulting in us most likely simply going out to retrieve it.

The only part that would fall would be beneath a break. The highest break that would likely happen would be within the atmosphere, and therefor would only make the bottom 0.03% of the cable, or 20 miles, fall. If I remember correctly, 20 miles is the cieling of the highest flying jet, the SR-71 Blackbird reconnaissance plane.

Even if it were to break, I doubt those who were responsible would be able to get their hands on such an aircraft and be able to fly it directly into the cable. Of course, precautions for such should be taken, but to bring the argument into the realm of reasonable probability, a break would probably only be a few miles up. Somewhere between five and ten miles I would guess.

The only way to attack the thing higher than the atmosphere would be to employ a space vehicle. I suppose an enemy government might use the plans of the recent civilian space craft and arm it with a nuke to break the thing off 60 miles up, or possibly a very wealthy terrorist might do the same.

I think the only thing that might possibly be something to actually worry about would be another space agency launching a nuke-armed rocket up to take the thing out at a few thousand miles. Then, the part in the atmosphere, with its friction, might begin to bend the thing over slowly as the top section starts to fall and it might fall horizontally across a very large area. Even then, however, it would not be catastrophic as the surface area affected, though long, would be very thin. I do believe this is the worst case scenario and is highly unlikely. Would Europe, Russia or China want to take such a thing out? Not Europe, for they would highly benefit from it as well. Russia too. The Chinese maybe, as they seem to want to become a monopoly, but would they go so far as to attack the thing and risk retaliation?

Jp wrote:

The press release is wrong, the end will be 42245 KM away from Earth - In geostationary orbit. Which means that if the top broke off, it would fall down.

42,245 kilometers = 26,249.826 miles

Geostationary orbit is approximately 35,786 km above mean sea level. That comes to about 22,236.3895 miles, meaning the wire will extend another 4,013.4365 miles, or so, beyond geostationary orbit. That's still a lot of length.

~X

[edit]
Interesting idea that could be employed:
http://en.wikipedia.org/wiki/Statite

Actually, it would be thicker at the top then the bottom. The bottom of the thing doesn't 'support' the elevator, the elevator is in orbit - it's constantly falling. It just happens to be moving aside fast enough that it doesn't hit. It needs to be thicker at the top because it has to support the stuff below it.

like osama bin laden isnt he a millionare
anyway if it gets hit at the ground lets say ppl are still near the ground and lets also say that theres a plane drove by terrost lets also say that theres the supposed biulding like covering on it a plane (just like in 911) has enohg fuel to reach more then a million degrees farenhite or whatever and thats what caused the biuldings to go down (it mealted the support beams i think)
that biulding better be heat rissitent and the elevator better go up qiuckly and if its like a rope might want a extra elevator with bags for puke

Jp wrote(in previous post):

There is no such thing as centrifugal force.

There most certainly is. Centrifugal force is the opposite of centripetal force. Centrifugal force repels an object, such as when you are rotating fast with a bucket in hand and you let it stay suspended horizontally, and its contents stay in the bottom despite it being tipped.

Jp wrote:

I've just realised a problem in the post I made: There wouldn't be any drag on the elevator, no matter how far out it was, assuming it was geostationary. (Not neccessarily geostationary orbit. Just geostationary) Why wouldn't there be any drag? The elevator doesn't move, relative to the atmosphere above where it stands, just as it doesn't move relative to the ground. Therefore, no drag.

The atmosphere does not stay still relative to the ground beneath it, not even the average atmospheric movement all taken together, therefor there will be drag. The elevator doesn't move relative to the ground beneath it, but it does move relative to the atmosphere. To clarify a bit better (the first sentence of this paragraph looks a bit confusing even to me), the total contents of the atmosphere moves slower and lags behind the ground beneath it in the earth's rotation.

Average atmospheric rotation aside, there is still wind, the bottom line of atmospheric displacement.

The point is, geostationary orbit minimises cable strain, and it causes no problems. So if the elevator broke, the 'space' end would just stay in orbit.

Geostationary orbit does have some problems, but they are simply problems that we can overcome without much effort. Employing at least a small amount of centrifugal force minimizes all problems and therefor does leave you with no problems. As such, even if you don't put the thing up at 60,000 miles, it would still be a good idea to place it at least a short distance above geostationary orbit altitude. Just enough to counteract the drag, if nothing else, as that would be much cheaper than equipping the thing with its own rockets to counteract the friction.

Also, there is the downward pull of the elevator climbing up as well. If you don't want to take a year to climb the ladder, you need to accelerate hard and produce a lot of earthward thrust on the entire thing, including the satelite on the end.

And when the elevator goes back down, it will most likely be left to accelerate by gravity, which means no thrust back in the opposite direction when it is on the second half of the journey. In fact, the thing will need breaks unless you want it to crash back into the earth at high speed, which means it will actually produce a downward thrust near the end of its return trip as well, though I assume this would be insignificant compared to the spaceward half of the trip.

Therefor, even if we did not have the atmospheric interference we would still have a downward pull. Bottom line, it is wise to put the thing above geosynchronous orbit even if by a small amount.

As another note concerning the elevating part of the topic, the amount of downward pull produced by this depends on the flexibility of the carbon nanotubes used. I know that they are flexible, but I know not how much. I don't think I need to explain how flexibility is a factor, as you can just think of the difference between yarn and steel. Pulling down on a steel rod has little effect on an object placed atop it, obviously. This brings to mind the question as to how much the cable will be contributing to holding the satellite up, if it will contribute at all.

All said, there are many factors. Many more than most people seem to realise.