Carbon nanotubes and space elevators

This was mentioned in the thread on the new x-prize but I wanted to start an actual thread on it as it is very interesting to me.

en.wikipedia.org...

Carbon nanotubes are essentially cylindrical carbon molecules that have extreme possibilities in creating circuit pathways considering they can be conductors or insulators and are measured on a scale of nanometers. One of my best friends is working with them I believe as part of his doctoral thesis. But anyway, I asked him and he said that they have the quality of being several hundred times stronger then steel so if you could weave them together as was mentioned in the other article you would essentially have a rope stronger then anything we've ever seen and possibly strong enough to be the transportation line of a space elevator (he didn't say anything about a space elevator just the part about how strong they would be.)

He also mentioned that we already have the technology to to start and make strands of them. Evidently they have some properties of attraction and repulsion so you can use that to coax them into lines large enough to be seen in a normal microscope. While this is of course a long way from being practical for what we are talking about, its a start and its definetely good news for the semi-conductor industry. But anyway, what do you all think? Is this something that we're going to see in our lifetimes?

Heres a recent interview with the head of liftport (a company behind space elevator development).
www.thespaceshow.com...

He also mentioned that we already have the technology to to start and make strands of them.

That are only about 3 meters long. Far short of the 15,000 km long strand we will need.

I'm taking a 4th year course in nanotech at school right now, and I don't think we are anywhere near the capability of making a 'space elevator'. The longest nanotubes to date are about 2-3 meters long. There are a lot of difficulties in manufacturing carbon nanotubes (CNTs) that still have to be overcome. The production of CNTs is so difficult that to buy one gram of the stuff costs roughly $500-$1000.

There are many reasons that CNTs are so laborious to create. One reason is that there are numerous different kinds of CNTs, all sorts of different lengths, diameters, shapes and sizes, and they all have different properties, and they are formed in a big mess that has to be sorted through to pick out the ones you want. (not to mention all the other more mundane carbon structures that form in much greater quantity) Until we see a way to mass-produce CNTs and improve their quality, the space elevator just isn't going to happen. Even then, I still have my doubts.

The place where I think CNTs are going to be extremely important is in microelectronics. CNTs (at least certain types) are excellent semiconductors, better than anything we have, including silicon. This means that, in theory, smaller & faster transistors could be built than anything we have now. These transistors have already been made (just google it, there's tons of stuff about them) but we can't mass produce them yet.

CNTs and fullerenes (soccer-ball-like structures of carbons) have massive potential, in my opinion, more than almost anything else out there in any field, because of the diversity of possible applications and their usefulness. I think this technology is definitely worth keeping an eye on.

Sometimes what u learn in school might not be the same as what is going on in industry, what i mean is that just because your professor says carbon nano tubes cant be mass produced it doesnt me its true. I remember reading a couple of years ago that nano tubes 3 cm long was the best researchers could do now they are

Yeah nanotubes are one of the major advancements of the future i think.

I read in n article somewhere.. the tere was a guy doing a feasability study into the space lift and concluded that the only missing part (in theory) was these Carbon Nanotubes and was suggesting the material was another 5 years away.

i recall somthing about the soviets using copper strings to lift objects or so into space.

I know one of the problems with using carbon fiber, is that over time microscopic cracks develop, tiny stress fractures, and these cracks threaten the structural integrity of your construct (whatever it is). There have been some advancements in self healing carbon fiber, but I'm skeptical about the application of said technology to nano-tubes; for two reasons. One is size, as previously mentioned, nano tubes are tiny, and there isn't any space to work with to contain the self healing epoxy. The other is gravity, the self healing system works on earth because the healing epoxy wicks into cracks naturally because of gravity, that wouldn't occur in space.

Spider silk might work for a space elevator. Perhaps resin coated, or interwoven with steel filament. I love the idea of a space elevator, and I'm sure we can overcome the technical hurdles to make it a reality. I'm just not sure nano tubes are the way to go. The technology is still so new and unproven, it would probably be more of a liability than anything.

Just my thoughts...

Originally posted by WyrdeOne
. The other is gravity, the self healing system works on earth because the healing epoxy wicks into cracks naturally because of gravity, that wouldn't occur in space.

The top of the lift is still within gravitational pull... look you only need to lift things close to the egde of earth gravity well not neccesarily OVER it. The lauching craft need to power themselves just over the edge of the gravity well... and hey presto launch!

[edit on 18/3/2005 by Corinthas]

The point that the carbon nanofiber cable need not make it all the way to space offers many other possible scenarios.

Perhaps cables attached to an inflatable (read - blimp) which is a technology already near to deployment in broadband access....imagine a floating platform large enough to support launches to space.

Just an idea.