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Can Quiet, Efficient 'Space Elevators' Really Work?
space.com ^ | February 21, 2014 12:25 PM | Leonard David

Posted on 02/22/2014 8:13:46 PM PST by ckilmer

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To: lurk

The idea is to use cable made from carbon nanotubes or similar, yet-to-be-invented materials. These have a tensile strength by weight of about 100 times more than steel. So, in theory, a cable could support its own weight into space and also carry additional payload weight. The problem so far has been the ability to produce continuous lengths of such cable.

While there are many obstacles to be overcome, the feasibility is very likely at some point. Some of the questions here sound like people mocking the idea that a jet made of metal could ever fly — carrying its own weight as well as that of cargo and passengers. Of course we now know that it is feasible and also a profitable and worthwhile accomplishment.

Space elevator technology could allow space colonization in a way that is not currently feasible.


41 posted on 02/22/2014 10:13:36 PM PST by unlearner (You will never come to know that which you do not know until you first know that you do not know it.)
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To: Usagi_yo
"That movie was creepy."

Was that the one with Tim Robbins? That WAS weird, but I liked it.

42 posted on 02/22/2014 10:15:20 PM PST by jackibutterfly
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To: unlearner
the feasibility is very likely at some point

Your opinion utterly without any basis in fact

43 posted on 02/22/2014 10:16:33 PM PST by from occupied ga (Your government is your most dangerous enemy)
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To: unlearner

No. The biggest problems will be space junk, weather like the jet stream, low flying satellites are NOT geo-synchronous so this station will have them whipping by quite often


44 posted on 02/22/2014 10:16:55 PM PST by GeronL (Vote for Conservatives not for Republicans!)
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To: ckilmer

Back in the day, BC (before children) I spent some of my free time gaming. In 1997, when Voodoo cards were all the rage, along came a space “sim” that really had some great gameplay. The intro, however, was (at the time) pretty awesome; still kinda is.

If you look at this youtube clip of that intro and skip to 7:15 you’ll see the concept of a space elevator in action. If you get a chance, check it out.

http://www.youtube.com/watch?v=C9AN1hpbw2Y


45 posted on 02/22/2014 10:17:35 PM PST by RedCell (Honor thy Father (9/6/07) - Semper Fi / "...it is their duty, to throw off such government...")
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To: from occupied ga

would be massively heavy

If made out of carbon one foot in diameter, 18,193,470 tons. I suspect that carbon nanotube cable 1 foot in diameter couldn’t even come close to supporting 18 million tons plus other stresses.

...........
carbon nanotubes are extremely strong small and light.


46 posted on 02/22/2014 10:21:46 PM PST by ckilmer
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To: from occupied ga; lurk
If made out of carbon one foot in diameter, 18,193,470 tons. I suspect that carbon nanotube cable 1 foot in diameter couldn't even come close to supporting 18 million tons plus other stresses.

IIRC, carbon nanotubes are hollow. Thus, a cable made up of them would not "weigh" as much as a solid length of either diamond or graphite. I don't know how big a cable would be necessary to support the load. Perhaps it would not need to be that large.

Also, the cable would weigh less as you ascended because of the centrifugal force acting on it. At geosynchronous altitude it would be "weightless." Above that altitude, it would actually pull "up" on the cable.

Your point may still be valid, but your calculation is not.

47 posted on 02/22/2014 10:30:45 PM PST by rmh47 (Go Kats! - Got eight? NRA Life Member])
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To: Nuc 1.1; ckilmer
How do we keep space junk from hitting the cable?

There is an awful lot of space in space. The odds of anything hitting such a relatively small cable would, I think, be slim. Not zero, but still slim.

48 posted on 02/22/2014 10:36:21 PM PST by rmh47 (Go Kats! - Got eight? NRA Life Member])
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To: ckilmer

Maybe.

Until that puppy snaps about 2200 miles up and the next thing you know, half of Poland is decapitated!

I’ve been around cables with high stress tension on them.
They can kill you so fast you won’t even realize you’re dead!


49 posted on 02/22/2014 10:37:51 PM PST by djf (OK. Well, now, lemme try to make this clear: If you LIKE your lasagna, you can KEEP your lasagna!)
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To: Empireoftheatom48; Beowulf9; ckilmer
Your right what happens in a hurricane?

If I remember my meteorology correctly, hurricanes always form at least several degrees latitude north or south of the equator and never cross it (something to do with the Coriolis effect, I believe).

Since the elevator MUST be built on the equator, hurricanes should not be a problem.

50 posted on 02/22/2014 10:43:05 PM PST by rmh47 (Go Kats! - Got eight? NRA Life Member])
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To: djf

ouch


51 posted on 02/22/2014 10:43:32 PM PST by GeronL (Vote for Conservatives not for Republicans!)
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To: ckilmer
I haven't yet seen anyone address what I believe may be the biggest problem to overcome with a space elevator: lateral acceleration of the load.

An object at the equator is moving about 1050 miles per hour due to the rotation of the Earth. An object at geosynchronous orbit altitude must move at 3430 mph to be "weightless." Therefore, as you pull an object from the surface to geosynchronous altitude, you must accelerate it by 2380 mph to avoid pulling the cable like a bowstring.

52 posted on 02/22/2014 11:03:21 PM PST by rmh47 (Go Kats! - Got eight? NRA Life Member])
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To: GeronL; unlearner
No. The biggest problems will be...weather like the jet stream...

I'm not sure if jet streams ever cross the equator, where the elevator MUST be built. I don't think they do, but I'll have to do some research to be sure.

53 posted on 02/22/2014 11:09:34 PM PST by rmh47 (Go Kats! - Got eight? NRA Life Member])
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To: Crolis
lunar cycles

tides for sure, but the fundamental problem is that there is an upper bound of strength for materials. Molecular bonds only have so much strength, and they just don't have enough. And before some genius out there says something about jet engines or bumblebees and thinks they've made some sort of point, consider the periodic table is well known as is the strength of molecular bonds

54 posted on 02/23/2014 12:26:18 AM PST by from occupied ga (Your government is your most dangerous enemy)
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To: ckilmer

Tether Ball.


55 posted on 02/23/2014 3:49:20 AM PST by Iron Munro ("Show me the man, and I'll show you the crime." - Lavrentiy Beria (& Eric Holder))
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To: ckilmer

What prevents gravity from pulling the cable down to earth? It’s not like there’s going to be a hook at the end of it attached to the moon........


56 posted on 02/23/2014 4:06:48 AM PST by Hot Tabasco (Was Occam's razor made by Gillette?)
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To: Carthego delenda est

The giant at the top is not going to be pleased.


57 posted on 02/23/2014 4:20:46 AM PST by aomagrat (Gun owners who vote for democrats are too stupid to own guns.)
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To: Nuc 1.1

Space junk, de-orbiting satellites, meteorites, ect. This thing is stationary, everything in orbit is traveling thousands of miles per hour.


58 posted on 02/23/2014 4:23:44 AM PST by Justa
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To: ckilmer

Then there is the problem of cutting across Earth’s magnetic field, turns out that pinholes in the material generate plasma and melt the material - see here:
http://www-istp.gsfc.nasa.gov/Education/wtether.html

I think this will have to wait until we master the manufacture of cosmic string ... www.andersoninstitute.com/cosmic-strings.html


59 posted on 02/23/2014 4:30:17 AM PST by PIF (They came for me and mine ... now it is your turn ...)
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To: lurk

sun, moisture, wind, airplanes....

Okay, let’s say we somehow get around all that. I’m just doing a little math here: Moving at 100 mph, It’s about a 26 day trip one-way, non-stop. A little over three weeks. Four if the speed drops to 90 mph. How much power is it going to take to a) lift something and b) keep it from falling at terminal velocity?

And I can just imagine humans on board with a breakdown happens. Not a crash, just a breakdown. How do you make repairs as say 200,000 feet?

And another thing: just for poops and laughs, I decided to check the weight on this pipe if it happens to be 1 inch carbon steel.

249,984 tons.

Yeah, I know, it would have to be a lot bigger than an inch.

So, can I go back to laughing now?


60 posted on 02/23/2014 5:29:33 AM PST by jimjohn (You don't get the kind of government you want, or the kind you need. You get the kind you deserve.)
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