cost of space elevator

flashgordon · 2003-06-09 22:27:05

I read that the cost to build the initial space elevator will be 40 billion; but, isn't that based on today's technology? I'm thinking the cost might not be that expensive ten to fifteen years from now on . . .

Algol · 2003-06-10 04:04:57

its probably important to note that it cant be built with todays technology........

I think the cost estimate is based on the cost of developing the technology and building it. Presumably the next SE after that would cost far less due to economies of scale etc

Its a bit like the pharamcuetical industry really.

Nick

Josh Cryer · 2003-06-12 08:07:39

I would think that once we had a carbon nano-fiber that reached space, people would be jumping to get a ride. So they'd be willing to pay an early fee.

What the space elevator people could do is just start charging for the elevator before it's even complete; that money alone could probably pay for it.

Free Spirit · 2003-06-12 20:29:40

The big variable here is how much it's going to cost to manufacture the nanotubes needed for the tether. Right now the price of producing quality nanotubes in quantity is very expensive. That price will have to come WAY down before the space elevator can hope to compete with rockets. Hopefully faster and cheaper production techniques can be developed which I'm optimistic they will considering the over all usefulness of cnt materials.

Josh Cryer · 2003-06-12 21:44:08

I think Algol put it really well. Carbon nanotube research isn't just going into space elevator technologies, it's going into tons of varying research. Think a cure for AIDs, but for composites. Development itself is a one time shot, once you have a manufacturing process, you're good to go. It just takes a lot of practice to get the right technique.

I think the advancements thread is a god thread to keep an eye on, just so one can see how fast carbon nanotech is progressing.

You know, I'm really confident that we're going to have space elevators within my lifetime.

flashgordon · 2003-06-12 23:03:23

i myself am scared; i think these terminator(and I like them more or less; but, don't take them so seriously; i can find holes in the story logic) movies are going to start putting up an anti-technology/knowledge movement. Not to mention all those Crighton movies; it's like the only sci-fi movies are technology scare movies.

Echus_Chasma · 2003-06-13 01:51:53

i myself am scared; i think these terminator(and I like them more or less; but, don't take them so seriously; i can find holes in the story logic) movies are going to start putting up an anti-technology/knowledge movement. Not to mention all those Crighton movies; it's like the only sci-fi movies are technology scare movies.

Thats what my English teacher was telling me today (I had a really in-depth conversation with him which took up the whole period, hehe). He was saying that the media and other sources are effectively pushing the idea that knowledge is bad. e.g. Mad sciencists etc are making people believe we cannot have technology because it could be used to kill. If that principle is applied to pretty much any major technological advance in history we would still be in the stone age. It's making people resist new technological developments. I can't explain it as well as him but like yeah. It's human nature to increase our knowledge, but it is our responsiblity as people who are into science and whatever to not become like the priests of old who held all the power and didn't share it. We need to share out our knowledge with all the ignorant people out there.

Apparently it was the development of nuclear weaponry that brought serious distrust towards the scientific community. So yeah... people are scared of new technology because it makes them think about human nature which they don't want to do. That's why it kinda sux that we haven't evolved as fast as our technologies have.

*sits back wondering if all that was coherent*

Free Spirit · 2003-06-13 21:14:20

Even though the dangers of technology are usually glamorised all out of proportion I do think we need to have some dialogues about where technology is taking us. It seems one of the biggest benefactors of nanotech research right now is the Pentagon which I have to be honest scares the hell out of me. I don't want to see the advancement of technology going in a direction that facilitates oppression of people by governments, corps, or whatever.

space_psibrain · 2003-07-25 18:08:22

as long as there is life there is hope, and as long as there are people lobbying against the military application of everything, there is still hope for a better world

Josh Cryer · 2003-07-26 08:24:44

Agree with you on that one Free Spirit... I won't really expound, but I think that's a common sentiment among rational people (ie, not clark :;): ).

Mace · 2005-08-31 14:42:08

Sooo...should the space elevator be a privately owned operation? At least they could sell stock, that would cover the cost along with ticket selling.

DonPanic · 2005-08-31 17:09:51

Sooo...should the space elevator be a privately owned operation?

Yes, it should be, because the cost of it is outrageously underestimated.

I visited space elevator promotionnal site and what is not said is that an object tighted from an earth point to a some kind of counterweight orbiting around Earth at about one fourth of the Earth to Moon distance is not a stable object.
Space elevator would be a perfect idea should the cables or ribons be rigid. This is not the case.
Space elevator terminal is summited to Eath-Moon tidal forces twisting the cables or ribbons which are flexibles and tends to exchange energy with Earth and Moon so that its position must be maintained by permanent energy supply by motors.
Energy supply means money. This is not mentionned in the site.

So how can people can evaluate the cost of a today not accessible technology ?
Laser beam energy supply to propell loads is a fantasy. When you know the % of laser energy conversion output, you realize that using doped carbon ribbons in order to make good electricity conductors is much more a cleaver option to supply energy to lift loads.

For these reasons, I can't take the space elevator site as a very serious one, just a new lobby of people trying to collect money as an own aim.

So it would be better that the space elevator promoters should finance it at their own risks

DonPanic · 2005-10-10 13:12:51

LO
a funny one : carbon nanotubes are quite elastic, because of there spiral structure that give them their strenght.
Just imagine a space elevator thighted to rubber-like behaviour ribbons
elongation value goes from 6 to 12%
Just big problems in the orbital stability of the whole thing...

noosfractal · 2005-10-10 13:58:38

Space elevator terminal is summited to Eath-Moon tidal forces twisting the cables or ribbons which are flexibles and tends to exchange energy with Earth and Moon so that its position must be maintained by permanent energy supply by motors.

The ribbon is under a lot of tension - it isn't going to be bouncing around. There was some worry that tidal resonances could cause destructive failure, but I thought a study showed it wasn't going to be a problem. You still need some active damping for sub-harmonics, but I think they can be solar powered - not free, but minor in comparison to the total cost.

Laser beam energy supply to propell loads is a fantasy. When you know the % of laser energy conversion output, you realize that using doped carbon ribbons in order to make good electricity conductors is much more a cleaver option to supply energy to lift loads.

The ribbon is going to be between 35000 km and 100000 km long. Wouldn't it have to be a superconductor as well as the world's strongest material? I think you are asking a lot.

DonPanic · 2005-10-10 15:40:43

Space elevator terminal is summited to Eath-Moon tidal forces twisting the cables or ribbons which are flexibles and tends to exchange energy with Earth and Moon so that its position must be maintained by permanent energy supply by motors.
The ribbon is under a lot of tension - it isn't going to be bouncing around. There was some worry that tidal resonances could cause destructive failure, but I thought a study showed it wasn't going to be a problem. You still need some active damping for sub-harmonics, but I think they can be solar powered - not free, but minor in comparison to the total cost.
The ribbon is going to be between 35000 km and 100000 km long. Wouldn't it have to be a superconductor as well as the world's strongest material? I think you are asking a lot.

All studies by Space Elevator promotors NEVER show the slightest problems, they are paid for !
100000 km long is more than 200000 km difference in regard of moon tidal action when space elevator terminal is close or far from moon. That's not a negectable action.
You cannot evaluate the space elevator costs. Nasa predictions about mass launching prices with Shuttle were total failures.
http://www.pa.msu.edu/cmp/csc/ntproperties/ Then go to electrical properties

Later, Phaedon Avouris [12] suggested that stable current densities of nanotubes could be pushed as high as 10000000000000 A/cm2.

If so, laser beam power transmission is promoted by morons

noosfractal · 2005-10-10 17:45:55

http://www.pa.msu.edu/cmp/csc/ntproperties/ Then go to electrical properties
Later, Phaedon Avouris [12] suggested that stable current densities of nanotubes could be pushed as high as 10000000000000 A/cm2.

At http://www.pa.msu.edu/cmp/csc/ntpropert … facts.html it says its resistivity is 10e-4 ohm-cm. Not bad, but the resistivity of copper is 1/50th of that. It is a little higher than that of stainless steel. Transmission losses would kill your efficiency (you'd lose a MW per km at 100 amps) and heat the cable to 1000 degrees. Perhaps those laser power guys aren't such morons after all?

reddragon · 2005-10-10 18:34:07

It seems one of the biggest benefactors of nanotech research right now is the Pentagon which I have to be honest scares the hell out of me. I don't want to see the advancement of technology going in a direction that facilitates oppression of people by governments, corps, or whatever.

I was thinking the same sort of thing recently when I read about that Pentagon sponsored robot race. The autonomous navigation technology they were developing could be used for a lot of constructive things (exploring Mars for example, or aiding rescue operations in disaster stricken areas). But they want to build these things to more efficiently kill people. The worst thing is that if NASA or FEMA or something had wanted funding to do this same thing, they probably would have been turned down.

DonPanic · 2005-10-11 03:40:47

LOFor

http://www.pa.msu.edu/cmp/csc/ntproperties/ Then go to electrical properties
Later, Phaedon Avouris [12] suggested that stable current densities of nanotubes could be pushed as high as 10000000000000 A/cm2.
At http://www.pa.msu.edu/cmp/csc/ntpropert … facts.html it says its resistivity is 10e-4 ohm-cm. Not bad, but the resistivity of copper is 1/50th of that. It is a little higher than that of stainless steel. Transmission losses would kill your efficiency (you'd lose a MW per km at 100 amps) and heat the cable to 1000 degrees. Perhaps those laser power guys aren't such morons after all?

Carbon nanotubes can behave as semi conductor or metal, depending on their structure, and conductivity can be doped.

For Cnanotubes elasticity, Cnanotubes are much stronger than steel wires, but if traction force reaches to a high value, instead of breaking out, C nanotubes will behave elastically, inducing strong oscillations in the space elevator. Altitude oscillations also mean orbital speed variations
I hope you realise consequences for a space elevator to have an orbital period slightly different from geostationnary. Earth Spacelift Station will have to let ribbons free in order to avoid any Space Elevator start rolling up around the globe.
That's a difference between froggies and US ways, Americans rush on ideas and will solve problems as they come, we'll try to study every problems before engagement. Each method as its strength and its weakness.
That's why Americans are in Iraq, not the froggies, because we're aware that winning peace is much more difficult than winning wars.

noosfractal · 2005-10-11 04:35:36

Carbon nanotubes can behave as semi conductor or metal, depending on their structure, and conductivity can be doped.

But still not a superconductor. Even if you can drop the resistivity to that of copper, you're losing 500 MW to provide 2 MW to the climber. The adaptive optics guys say they can get 3% efficiency to GEO, so to beat them you're going to need a resistivity 1/10th that of copper, with no added weight from the doping or no loss in effective strength. Good luck.

For Cnanotubes elasticity, Cnanotubes are much stronger than steel wires, but if traction force reaches to a high value, instead of breaking out, C nanotubes will behave elastically, inducing strong oscillations in the space elevator. Altitude oscillations also mean orbital speed variations
I hope you realise consequences for a space elevator to have an orbital period slightly different from geostationnary. Earth Spacelift Station will have to let ribbons free in order to avoid any Space Elevator start rolling up around the globe.

I scanned a half dozen papers on oscillations. As long as your length is not some integer multiple of the lunar or solar resonance periods, the oscillations are "tame." There are worries about the climbers inducing longitudinal oscillations, so that needs looking into, and twisting oscillations are harder to model. You're right, some active damping will be required, but it doesn't look like a show stopper. GEO is pretty stable.

DonPanic · 2005-10-11 14:19:00

LO

[ GEO is pretty stable.

You mean the Space Elevator is pretty stable ?
Let' argue on this point.
They say that a terminal counterweigh is tighted to SE terminal.
In your opinion, which is its orbital speed so that it would be in a straight line with the SE main station on Geo orbit ?

noosfractal · 2005-10-11 16:16:40

They say that a terminal counterweigh is tighted to SE terminal.
In your opinion, which is its orbital speed so that it would be in a straight line with the SE main station on Geo orbit ?

I guess that depends on how far the counterweight is from GEO?

I see though, that Steindl and Troger have called the no-counterweight version of the elevator (they use the term sky hook) into question in a recent (2005) paper. Let me read their paper and I'll get back to you.

noosfractal · 2005-10-11 18:29:08

I see though, that Steindl and Troger have called the no-counterweight version of the elevator (they use the term sky hook) into question in a recent (2005) paper. Let me read their paper and I'll get back to you.

So it looks like you need some sort of counterweight at GEO just from a stability point of view. Interestingly, lighter cables need larger counterweights for this issue. However, for a 65 GPa cable, Steindl calculates a minimum 6000 kg counterweight - which isn't going to be a problem - we're not even talking asteroid. Papers addressing other orbital stability problems (like the ones caused by the Moon and the Sun) are also referenced.

Looks like a cable that goes further than GEO still needs more study though.

DonPanic · 2005-10-12 02:19:33

LO

They say that a terminal counterweigh is tighted to SE terminal.
In your opinion, which is its orbital speed so that it would be in a straight line with the SE main station on Geo orbit ?
I guess that depends on how far the counterweight is from GEO?

Lets say 92000km ?

I see though, that Steindl and Troger have called the no-counterweight version of the elevator (they use the term sky hook) into question in a recent (2005) paper. Let me read their paper and I'll get back to you.
So it looks like you need some sort of counterweight at GEO just from a stability point of view. Interestingly, lighter cables need larger counterweights for this issue. However, for a 65 GPa cable, Steindl calculates a minimum 6000 kg counterweight - which isn't going to be a problem - we're not even talking asteroid. Papers addressing other orbital stability problems (like the ones caused by the Moon and the Sun) are also referenced.Looks like a cable that goes further than GEO still needs more study though.

Either an object is in balance at geo, then if you pull it with a traction motion, you disbalance it, or there is a traction force opposite to your traction to keep the balance, that's physical basic law, sir

noosfractal · 2005-10-12 03:15:08

Lets say 92000km ?

Oh I see what you want. Maybe this will put your mind at rest ...

http://www.mit.edu/people/gassend/space … r-of-mass/

The main thing being that you can't treat the space elevator as a point mass like normal satellites, so you have to take into account the gravity field - which varies by a factor of 300 over the length of the cable. The lower portion counts for much more than you might think.

Either an object is in balance at geo, then if you pull it with a traction motion, you disbalance it, or there is a traction force opposite to your traction to keep the balance, that's physical basic law, sir

Yes but you and I are also subject to lunar forces - magnitude matters. You're right - there is going to have to be active adjustment of the orbit. The question is the order of magnitude. Basically the question comes down to: can I use solar power, or do I have to put a nuclear reactor at GEO?

DonPanic · 2005-10-12 07:14:02

LO

Lets say 92000km ?
Oh I see what you want. Maybe this will put your mind at rest ...
http://www.mit.edu/people/gassend/space … r-of-mass/
So in general, for an orbit that extends over a great range of altitudes, the orbit will be faster than the orbit at the center of mass altitude. In conclusion, even for an elevator not attached to the Earth, the center of mass should be above GEO.

So, its mean that the space elevator isn't geostationnary, such as the SE earth station should be mobile and abble to fly over mountains

The main thing being that you can't treat the space elevator as a point mass like normal satellites, so you have to take into account the gravity field - which varies by a factor of 300 over the length of the cable. The lower portion counts for much more than you might think.
Either an object is in balance at geo, then if you pull it with a traction motion, you disbalance it, or there is a traction force opposite to your traction to keep the balance, that's physical basic law, sir
You're right - there is going to have to be active adjustment of the orbit. The question is the order of magnitude. Basically the question comes down to: can I use solar power, or do I have to put a nuclear reactor at GEO?

A nuclear reactor ? That isn't simple nuke powered batteries.
Do you know how heavy is a "nuclear reactor" ? Is it included in the costs prevision ?

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