Space Elevator, Ho!

flashgordon · 2005-08-18 22:51:22

http://www.nature.com/news/2005/050815/ … 815-8.html

srmeaney · 2005-08-18 23:05:59

The ribbons are transparent, flexible, and conduct electricity. Weight for weight, they are stronger than steel sheets, yet a square kilometre of the material would weigh only 30 kilograms. "This is basically a new material," says Baughman.

Now all they need to do is weave them into nice strong cables that can be suspended from a Small moon in Orbit and Use them as a Skyhook to lift and lower ocean liner sized space transports into and out of orbit rather than an Anchored elevator cable.

Once in space the orbiting Ship can pick up one of the very powerful fission motor space tugs designed to push a million tonnes through space to Mars.

Ooh that is a thought: At thirty Kg a square KM, Are they any good as Solar Sails and Mars Domes?

John Creighton · 2005-08-18 23:49:01

http://www.nature.com/news/2005/050815/ … 815-8.html

That is amazing. I don't know if the material will be strong enough for a space elevator but the amount of applications this stuff will have will be amazing. I didn't expect this much progress so soon.

Rxke · 2005-08-19 03:28:56

The nanotubes tangle together just enough to keep a ribbon growing

Doesn't sound very strong to me. No cable stuff, I'd guess. Still, a very interesting development.

Rxke · 2005-08-19 06:48:15

Hmmm... I retract that. It's stronger than Kevlar, and they're going to try and win some elevator prizes with it, so this might be something special.

Gets more interesting by the hour, this!

Rxke · 2005-08-19 07:13:32

"The new sheets have many of the same abilities as the single nanotubes, although their strength does decrease, becoming comparable to that of high-strength Mylar and Kapton"

so not as strong as Kevlar, probably...

-sigh-

Wish they posted some hard numbers, somewhere...

Dragoneye · 2005-08-19 08:50:10

this stuff would be great for so many uses... imagine a 5 layer body molded peice... that stuff would protect you so well... or for skin on a plane to keep weight down. Wiring for vehicles since its conductive light, and thin. woven into a solar sail. and so on....

I just wonder how much this stuff will cost.... i would love to get a roll to play with it though. even if it costs $50 for a roll, i would be willing to get some just to experiment....

flashgordon · 2005-08-19 11:05:50

yes, if anything, this is just a symbol of the progress made . . . they'll just keep making observations and experiments and will probably find a way to get those nanotubes inline or stuck together.

srmeaney · 2005-08-20 04:31:21

Alright, lets say the nanofibre ribbon is useful in constructing what is essentially a km long, 100 m diameter sock and is of sufficient material strength to allow light while having earth air pressure and temperature on the inside and mars pressure and temperature on the outside. We could use it as a greenhouse and the airpressure difference would keep it inflated. We would then need to mix our own growing media from the Mars top soil.

We would also require a heat dissapation mat to isolate the greenhouse from ground. This would be a multi-layer structure functioning as a radiator. It is still a floor mat with pockets of air under pressure. The air would move about as people walked on it.

A Greenhouse would require two payload modules the size of large habitats because both the greenhouse component and radiator floormat would need to be rolled up very tightly to load.

Mars Greenhouse (100m x 1000m) purchase&deploy=$20,000,000,000.00

reddragon · 2005-08-20 09:39:03

Alright, lets say the nanofibre ribbon is useful in constructing what is essentially a km long, 100 m diameter sock and is of sufficient material strength to allow light while having earth air pressure and temperature on the inside and mars pressure and temperature on the outside. We could use it as a greenhouse and the airpressure difference would keep it inflated. We would then need to mix our own growing media from the Mars top soil.

Such things have been suggested with other materials, but the nanotubes would probably be stronger than other materials. It might also make sense to use nanotubes in constructing habitation domes and other structures besides greenhouses.

The nanotubes tangle together just enough to keep a ribbon growing
Doesn't sound very strong to me. No cable stuff, I'd guess. Still, a very interesting development.

The full sentence was "The nanotubes tangle together just enough to keep a ribbon growing, without jumbling up into a huge ball." A scientist was then quoted as saying "They've found the magic spot." The implication, I think, is not that they tangle together just barely enough, but that they tangle together enough but not too much.

I don't know if these ribbons will be strong enough for space elevator cables. But I suspect that strong enough nanotube cables will be available eventually, probably soon. The technology is still developing and there is still plenty of room for improvement.

John Creighton · 2005-08-20 12:06:51

I wonder how this stuff would work for balloon applications.

flashgordon · 2005-08-20 21:11:17

yes, this stuff can be used for more than just a space-elevator(with more development), but far better space rockets! Just wait till the space tourism industry gets going and gets their hands on this stuff!

GCNRevenger · 2005-08-20 21:28:30

This is still a loooong long way from making a practical space elevator material

Oh, and its pitch-black opaque, so you can't make greenhouses with it.

srmeaney · 2005-08-20 22:14:09

Oh, and its pitch-black opaque, so you can't make greenhouses with it.

What picture are you looking at?

Looks sufficiently transparent for a shadehouse with reduced UV requirements.

GCNRevenger · 2005-08-20 22:30:24

On Mars you need all the light you can get, unless you want to spend some bigtime electrical budget on lighting. Heck, growing things on Mars is already halfway a shade-house, even in full sun. Even a modest dimming is not acceptable.

And how thick does it need to be to resist puncture or bursting?

srmeaney · 2005-08-20 22:56:19

And how thick does it need to be to resist puncture or bursting?

A two weave layer should bring it down to fifty percent UV penetration. A phosphor coating will produce lots of light from that level of UV. Not enough for sunlight extreem species of plant but sufficient to illuminate as though you were in a rainforest with heavy foliage. That alone is sufficient to produce a biosystem.

Sure its no good if we cant produce food we are use to but it can be sufficient to produce Fungus, Fishfarms, snail meat...

Shaun Barrett · 2005-08-21 06:55:34

Reddragon:-

But I suspect that strong enough nanotube cables will be available eventually, probably soon. The technology is still developing and there is still plenty of room for improvement.

I agree.

This stuff is very exciting but I don't know why everyone is so surprised. Once carbon nanotubes were invented (or should I say discovered), it was only ever going to be an engineering development problem between us and a viable Space Elevator cable material.
-- I'm on record as saying I think a viable cable will come sooner rather than later and news like this does nothing to change my mind.

GCNR:-

This is still a loooong long way from making a practical space elevator material
Oh, and its pitch-black opaque, so you can't make greenhouses with it.

Tsk, tsk, GCNR.
I think your ingrained 'bah-humbug' pessimism is showing!

GCNRevenger · 2005-08-21 07:48:03

Well, for a CNT composite cable to be strong enough, there are a few things that it probobly has to be:

-The tubes must be longer, preferably of arbitrary length (like centimeters), which right now they are only a fraction of this length.

-The tubes in the composite should not be tangled up at random, because their fantastic strength arises most from being pulled on their axis, they need to be alligned with the elevator cable. We can't do that very well yet.

-A composite binder must be made that prevents the nanotubes from "slipping" out, just like rebar pulling out of concrete. Strategies of cross-linking the nanotubes with reactive oligomers or short functionalized nanotubes and such are possible, but will need development.

Oh, and you've gotta figure out how to make this stuff cheaply by the kilo, not the milligram... High-grade stuff can run as high as $2,000/g, and take some days to make.

mboeller · 2005-08-21 12:54:44

Another article about this material: http://www.physorg.com/news5890.html

While sheets normally have much lower strength than fibers or yarns, the strength of the nanotube sheets in the nanotube alignment direction already approaches the highest reported values for polymer-free nanotube yarns.

John Creighton · 2005-08-21 13:12:18

Another article about this material: http://www.physorg.com/news5890.html
While sheets normally have much lower strength than fibers or yarns, the strength of the nanotube sheets in the nanotube alignment direction already approaches the highest reported values for polymer-free nanotube yarns.

Interesting. I was wondering if these would be good for solar sails. I guess it has already been suggested.

Shaun Barrett · 2005-08-21 17:37:14

GCNR:-

-The tubes must be longer, preferably of arbitrary length (like centimeters), which right now they are only a fraction of this length.

In fact, a 4cm-long single-wall carbon nanotube was grown in September last year. (http://www.lanl.gov/news/releases/archive/04-076.shtml)
-- Things are moving along very quickly. Sometimes it's a job to keep up.

[P.S. I love your sig.! ]

GCNRevenger · 2005-08-21 21:42:41

Hmmm, news to me... okay, now can they make about 800 tonnes of it?

Shaun Barrett · 2005-08-22 02:08:33

GCNR:-

... okay, now can they make about 800 tonnes of it?

There's no doubt in my mind that they'll be producing thousands of tonnes of it in just a few years. The uses for material like this are limited only by the imagination and things will start leapfrogging as currently manufactured CNTs are incoporated into commercial products, creating markets for ever-longer and purer CNTs. The evolving market demand will then spur more research and development, and so on and so forth. "Where there's a buck, there's a way"!
-- The beauty of the CNT is that it isn't all-or-nothing. There are applications for the technology at each stage of its development and that spells success for Space Elevator grade material in the not-too-distant future.

Of course, whether or not Space Elevators themselves can be made to pay their way is an all together different point. There was a discussion about that very point here at New Mars about 2 years ago but I can't remember if a consensus of opinion was ever reached or not. I know some people were very doubtful that enough paying customers could be found to justify the $5-10 billion cost of setting up an elevator, with all its associated infrastructure. Having to place the ground station in the South Pacific Ocean, west of South America, for various reasons including storm frequency and terrorism, didn't help much. I suppose it would be much more convenient if the equator ran through Dallas or Denver or Cairns, or some such place!

Trebuchet · 2005-08-22 07:06:16

Honestly... just make it a bit longer and drag the end on Earth someplace a bit more defensible. The thing is 25,000 miles long, more or less, a comparatively little curve near the end probably won't throw things off, right? It would be like having a twenty foot rope with one end sunk in a rubber ball, even if you align the rope so it's coming out of the 'pole' of the ball, the other free end will circle around at the equator.

Shaun Barrett · 2005-08-22 07:18:58

Trebuchet:-

Honestly... just make it a bit longer and drag the end on Earth someplace a bit more defensible. The thing is 25,000 miles long, more or less, a comparatively little curve near the end probably won't throw things off, right?

I think I normally agree with most of what you say, Treb.
But I don't believe curving the bottom of the SE cable off-equator will work. To be commercially viable, I think the cable will have to have a lot of traffic on it, going up and down simultaneously. To support that kind of tonnage, it will have to be under considerable tension - provided by ensuring the centre of gravity is somewhat above geosynchronous.
-- The cable will be very taut. As I see it, no curves will be possible.

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