Scientist Sees Space Elevator in 15 Years

[errorist]

A carbon nano tube pipeline from the Equator to geo. orbit could pump massive amounts of H2 and O2 to space to be stored as rocket fuel. The pipeline would only have to be 1/4 inch diameter.

http://www.newmars.com/cgi-bin/ikonboard/ikonboard.cgi?;act=ST;f=5;t=198;st=0

 

[russ_watters]

This doesn't change the fact that carbon nanotubes are not going to be a useable construction material any time in the forseeable future.

 

[notal33t]

Wakey wakey! Surprise surprise surprise!

I think you miss the point. An ant that's 1cm long can carry something like a hundred times its own weight, while a much larger ant (not sure how long) wouldn't even be able to support its own structure. The point is that structural support issues scale exponentially: doubling the height of a building requires four times the support structure.

But that isn't even my biggest cause for skepticisim. They call them nanotubes for a reason: they are small. They need to be able to make them many orders of magnitude longer before you can even hang a chandalier from one. Like enigma said - wake me up when they make one longer than a foot.

==
I thought to answer by using as a paraphrase.
Skepticism in the defense of science is no vice. (or is it?) :zzz:
It's obvious from your comments that you folks ain't awake!
You sort of remind me of the 'scientists' that argued that rockets could never fly in space because they didn't have air to push against.

Well I guess there's those that see, and those that can't see!

 

[russ_watters]

You sort of remind me of the 'scientists' that argued that rockets could never fly in space because they didn't have air to push against.

Well I guess there's those that see, and those that can't see!

There's a reason you put "scientists" in quotes in that sentence: they weren't. Sorry, this isn't even close to the same thing.

 

[errorist]

Well the Japanese have made them a few centimeters long now. Now how many times are they longer than wider? I know they are but a few H2 atoms in cross section.

 

[Invader_tech]

You have to think too, the governments of the world have technollogy that can be well 50 years into the future, they simply decide not to tell us. During the time of when the U.S. first started testing hydrogen bombs, they did it withought the public knowing, and as a coverup the U.S. publicly made it look as if it was difficult to lift a few pounds with their powerful rockets, whilst they were in fact at the same time sending several kiloton bombs up with ease.
It may sound incredibly difficult to us now, but for all we know, they might have had this planned out 20 years ago. And so, I am open to the possibility that it CAN happen

 

[Kenneth Mann]

This seems like an incredibly difficult and ambitious idea. I'm not sure that the proponents recognize this by orders of magnitude. I don't say that it is impossible, but that it will be very, very, very difficult and expensive. Sometime back, I undertook a small exercise to determine very crudely how much effort would be required. I decided that it could be possible someday, but that it would be a long time off.

First, its length wouldn't be to Earth-synchronous altitude, but roughly twice that far. Reasons and implications of this are:

a) Earth synchronous altitude is necessary for the cable's platform to orbit the planet at the same rate at which the planet turns (to keep the cable roughly straight). As the cable extends down, however, this (one revolution per day) rate is not enough to sustain the cable in orbit, it will go from weightless to progressively heavier as the cable extends down, to the full weight at surface level. This imposes not only an enormous tensile strength requirement on the cable, but also a huge weight on the orbiting platform (or whatever is there) at synchronous altitude. To keep this weight from pulling the 'platform' down, the cable would have to be balanced by a roughly equal cable beyond that platform, so now we have a cable roughly sixty thousand miles tall.
b) The platform is now being pulled in both directions (an equal amount, in order to balance out the forces and keep the platform from being pulled down). This means double the tensile strength requirement. My intuition is that this will probably require something orders of magnitude stronger than 'nanotube' structures. (I leave it to others to determine.)
c) Orbital characteristics will cause the cable to try to wrap itself around the Earth like a maypole, especially as it is being dropped and extended from the platform. This will add additional loads and complications.
d) In order to stabilize the platform(s) in orbit they will possibly have to first be linked with an additional series of cables that circle the Earth (at synchronous altitude. This would add the need for a set of cables roughly two hundred thousand miles long. The saving is that this cable would be weightless, and not add the strain of its weight.
e) As the cable comes into the atmosphere, additional problems will accumulate.
From this I feel that the cost will be a lot higher than proponents estimate, (more likely, closer to ten trillion dollars than to ten billion). It would probably be easier to build a suspension bridge to Hawaii, but that's just my feeling.

KM

 

[hitssquad]

First, its length wouldn't be to Earth-synchronous altitude, but roughly twice that far.

The anchor is relatively massive. That is why it is proposed as flying at an elevation of 30,000 miles instead of 44,000 miles.
http://www.google.com/search?q="30,000+miles"+anchor+elevator

 

[Kenneth Mann]

Sounds interesting, but I can't imagine the governments of this planet allowing anyone to drag a large asteroid anywhere near to us; especially after the what the dinosaurs apparently went through.

Maybe we should first try this on Mars where it will be easier to prove the concept out, and get a handle on the ultimate costs. If it can be made to work there then we can better determine if it is worth the very high price that would be entailed here. I still think the price will be in the trillions, not 500 billion, and definitely not 10 or 15 billion.Besides, Mars has a couple of small moons that might be suitable; and easier than pulling in an asteroid.

KM