BeanStalk Conduction limits



This is a major beef to me. Naysayer keep talking about the beanstalk as it is made out off copper, considering it's lenght and small cross-section it would have a very high total resistance even if made out of a good conductor. However the fibers are imbedded in a non-conducting resin and the max tensional strenght of a composite material occurs when the fibers are not touching but rather have 100 percent coverage with resin. This type of composite will be a poor conductor no matter what the internal fibers are made of.
Additionally, a question I asked before that was never answered. Someone claimed that bucky tubes were Ballistic SuperConductor with an internal resistance of less than 7000 ohms no matter what thier length were, but no-one stated what happens if two BSCs touch each other in series - does the total resistance still stay at the same value as a single cable or the sum values of both cables?
Earl Colby Pottinger
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Well, the scale and chemical properties of nanotube fibers make that a little more complicated. Constructing strong composites with nanotubes is still an unsolved problem. It may turn out to be best to have nanotubes chemically bonded to each other, the only "binder" being functional groups attached to the nanotubes. It's still unlikely to be highly conductive unless designed to be.

As I understand it, two nanotubes end to end will have twice the resistance.
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wrote:

it
conductor.
the
At some point in a thunder storm it will start to conduct or the dust and dirt on it will and the resulting lighting bolt will detach the anchor.
Gordon
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So, you clad the bottom 10Km in sufficient aluminium/copper to conduct the bolt.
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Dear Ian Stirling:
wrote: ...

and
the
You'll attract the bolt, and fry the cable with the heat. Better to run "dust bunnys" along it when it is not otherwise in use.
David A. Smith
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Odd, I don't see any fried structures out there today when a properly sized and ground cable is used.
BeanStalks are non-conductors , there is not enought of a current flow for them to heat up.
Lighting rods with proper sized and grounded cables conduct power with such low resistance the copper cable does not heat up by much even after repeated lighting stikes.
Earl Colby Pottinger
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Dear Earl Colby Pottinger:
wrote:

dust
anchor.
conduct
run
sized
The cable has to be replaced after a strike. Or weren't you aware of this?

for
One of the pro-beanstalk supports was going to wrap the lower end in foil. And even the plasma adjacent to the tether (such as does occur along a wet/dirty surface) will damage the tether.

such
repeated
They have to be replaced peridocially. Just as your lower end tether will have to be.
David A. Smith
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In sci.space.policy "N:dlzc D:aol T:com \(dlzc\)" <N: dlzc1 D:cox T: snipped-for-privacy@nospam.com> wrote: <snip>

Which is not a really big issue. The weight of 10Km or so of tether is well within what can be lifted by one car. You just hook on a special car, which climbs to 10Km, cuts the old cable, ties it on to the new one, and then pays out the new one as the ground reels it in, before tying on the other end and coming back down.
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Dear Ian Stirling:
wrote:

will
one
The atmospheric section, as has been correctly pointed out, is serviceable. The denial by some that the tether will be subject to damage by lightning strikes is beyond me to fathom. Chances are it would continue to "pick on" the same one (unless they are conductive), until it parted, so it should be unlikely that all of the others would fail in a single storm.
David A. Smith
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Better to have it pay out the new one on the way up. That way, it has less work to do...it doesn't have to lift the entire mass of the new portion all the way to the attachment point. It could also just lay a new layer over the old cable rather than replacing it...though a full replacement would eventually be required to reduce the cable weight.
Huh...maybe stack the layers, one side being oldest. New layers are added at one side, old layers removed on the other. When you've moved all layers of the lower segment to the opposite side of the upper segment, it's time to replace the upper segment as well. Further up out of the atmosphere, you just patch as needed.
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That way you might get issues with the cables tangling.
Which would be bad, though admittedly not as bad as a severing.

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I noticed you did not answer a single question I ask or address a single point I raise. If the fibers are embedded in resin why must it start conducting. Why would dust collect on a vertical ribbon. When have you hear/seen that dust collected on the outside of any manmade structure conducting lighting? How can dust made of mostly Silicon Dioxide conduct power?
You seem to be trying your level best to claim BeanStalks are damaged by lighting, but all your claims are based on designs only a child would built. Try entering the real world where man-made structures get hit by lighting twenty times in a single day and keep on working.
Earl Colby Pottinger
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Dear Earl Colby Pottinger:
:

and
He said "dust and dirt". You were answered.

It works for vans, buidling walls and windows, and flagpoles. Do you think nature makes exceptions based on your intended use?

Lightning rods, yes.

Since when is dust "mostly silicon dioxide"? Ever heard of doping? Ever heard of hygroscopic materials? Lightning follows any path that gets it to ground with minimum breakdown voltage. Surface conduction is quite easy to induce.

built.
You on the other hand are burying your head in the sand. The tether will be prone to lightning strikes. You can minimize the strikes... how? Cleaning, keeping it dry, keeping it as non-conductive as possible, seeding the ground around it with a reverse static charge, more?
David A. Smith
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On a vertical ribbon?

Right, now you find me one that has collect enought dust to conduct power.

I ask for a structure - you a non-conducting one like the BeanStalk is. ]

OH, I see! Someone is going to dope the dust on purpose. Again I ask show me a real world example of dust collecting on a manmade structure conducting power.

And who bothers to do any of those things to present non-conducting structures today? The fact is any well design non-conducting structure needs no maintainence to survive lighting strikes. The current flows are just too small to do any damage. Worse for your claim on things to do to prevent stikes, Gordon says nothing you do will be good enough - lighting is going to turn your structure to plasma and blow it away period. Re-read his post if you don't believe me.
Earl Colby Pottinger
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What about rain. Last time I looked, this was not uncommon around thunderclouds. Even if the drops don't wet the tether, it still provides a space for the raindrops to hang in a tighter than usual formation.
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Dear Ian Stirling:
:

dust
anchor.
single
start
Yep. Even teflon(r) gets wet, and dirty. Kevlar has more affinity for water than teflon does.
David A. Smith
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Dear Earl Colby Pottinger:
:

dust
anchor.
single
Yes.
think
power.
Power poles have to be cleaned, or weren't you aware of this? I seem to recall these are vertical...

What did you say here?

Ever
it to

easy to

show
conducting
Done. For your edification, "doping" is simply the addition of scattered discontinuities. This would be dust, electrostatically attracted to the insulative tether material (assuming we are still talking about kevlar+coating).

by
lighting
will
Now many of them extend more than 1000 feet from the ground? How many of them have lightning rods that are higher than the structure?

too
It melts copper bussbar, 1/2 in diameter. It is hundreds of thousands of amps, for a very short time. The busscar has to be replaced. You may be thinking about the stray filaments that pass through those people that get to "live".

going to

if
You must be selling stock in a company that is "planning" on putting one of these up. Your blindness has to be intentional.
David A. Smith
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Dust collect on everything and everything develops a charge. The charge starts a leader for the bolt to follow and plasma of the vaporize air, beanstalk, copper cladding, gondola and fulgurites in the soil conduct the lighting.
The effects of lighting reach well into the stratosphere. Google elves and sprites.
Gordon
:

and
built.
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Not on Vertical Surface it does not.

You are walking around with a charge all the time? The Cable is grounded thus it can't keep a charge.

Really? Can you show me a single building, tree, or power pole that shows any major plasma damage. What you claim does not happen in real life. And I noticed you still avoided showing any real examples.

sprites.
Then name me a single manmade structure hit by lighting becuse it collect dust.
Earl Colby Pottinger
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You never have to clean your windows? BTW, something I haven't seen mentioned yet...this is likely to be at sea, so the dust will contain large amounts of salt...a newly dampened cable will have a fairly conductive layer of saltwater on it.

Actually, it will develop a charge...if it's a good conductor, it will be close to the charge of the ground. If it's a poor conductor (more likely, especially over the distances involved), the charge at a given point on the ribbon will depend on that of the nearby air. Even a dirty, damp cable will not be a great conductor.

Well, I have a scarred tree outside...but that's more from the current superheating the sap and living tissue. Tree bark makes a much better conductor than wet dust.
Utility poles don't need to be cleaned to eliminate discharge. The ones you see may be kept clean just to keep them clean...nobody has ever cleaned any of the poles around here. And buildings have lightning rods...and the cables only need to be replaced if they are damaged, which does not happen regularly.
Corona effects (St. Elmo's Fire) will probably cause slow damage (ozone, atomic oxygen, nitrogen oxides, etc), and lightning strikes along the cable are quite possible, but they won't be catastrophic. I suspect replacing the bottom hundred meters or so due to cumulative damage may be a fairly regular maintenance procedure. Dumping the counterweight (or starting up emergency thrusters on it) and reattaching the elevator will be far less common. Most lightning will probably hit targets around the elevator...a simple steel tower will be a much better target than a damp elevator cable.
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