Space elevators a fantastic idea that maybe someday could be reality?

[Nibb31]

Why is the picture in the O.P. In Indonesia?

Anyway I know how to make one, just get a satellite to orbit in Geosynchronous orbit and have it carry special graphene wire 390km of it, when the wire hits the ground carbon nanotubes would go through the side cables to reinforce it and keep it up. Send stuff up and build a station. Also it should be stronger if the cables supported a circular cart.

That's always been the conceptual plan for building a space elevator, except that it's 36000km, not 390km. Do you have any idea how much a 36000km spool of graphene or carbon nanotube wire weighs?

Oh, and actually, you need twice that weight, because as you unspool the tether downward, you need to unspool a counterweight tether in the other direction to keep the center of mass at constant GEO altitude.

[Everten P.]

Sorry for the height problem typing after I went to buffalo wild wings makes it hard to do anything. lol anyway if the wire was attached quickly wouldn't centripetal force straighten it along with the nanotubes running up the sides? also a way you could get up is by having the satellite pull on the carts. It's not going to affect the satellite because it is applying structural force down on the and this would mean that only a few carts can be pulled up at a time but it would mean that heavier cargo can be pulled up. If I am wrong about anything forgive me I am kinda new to astrophysics but I know a bit.

Also the nanotubes would come from the ground up

Edited July 4, 2014 by Everten P.

[randomness5555]

Simple answer-everyone is talking about building what is essentially a long cable attached to a small station type thingy at the other end. How about a sort of cone shaped tower-maybe 100 miles wide, 80-90 tall and a width of maybe 1 at the top. It would be large enough for the top floors to be outside the atmosphere, but would have such a large footprint it could happilly stand up without super-materials. Okay, so it would probably need some very special materials still, but it wouldn't require them to be as strong as a cable would have to be. My thought would be that it would also be a self contained city and research base. It would also probably need to be an international project due to the immense cost-but I think cheap space travel would be worth it. My other idea would be that at this scale you could run ordinary-ish train tracks up the tower to get cargo to space.

[Nibb31]

How does an 80-mile-high tower lower the cost of reaching orbit ?

Also, the sheer mass of the tower would crush itself.

Edited July 4, 2014 by Nibb31

[PakledHostage]

How does an 80-mile-high tower lower the cost of reaching orbit ?

Pffftt... Because we all know that space starts 60 miles up and that you float when you get there. Heck, some kids showed NASA a thing or two by sending a lego guy into space with a balloon. NASA. What a bunch of rocket scientists! lol

[Rakaydos]

There is a mountian range in south america that has a peak almost on the equator that's the furthest point on the ground from the center of earth. (sea level is lower around everest, so everest still has a height above sea level advantage)

This mountian, being solid rock, is stable where a hollow tower might not. Build a railway to the top, and it would be one of the best launch sites on earth, or the best place to site a space elevator.

Unfortunately it's in the middle of a third world nation with no money or interest in a space program.

[randomness5555]

How does an 80-mile-high tower lower the cost of reaching orbit ?

Also, the sheer mass of the tower would crush itself.

Okay-first, I never said it would make it cheaper. It's just an alternate idea of how to do it.

As for the mass thing-how do you know? Who knows what materials we'd have by the time it came to actually building it-which would not be for a few decades at least.

[PakledHostage]

As for the mass thing-how do you know? Who knows what materials we'd have by the time it came to actually building it-which would not be for a few decades at least.

I'm guessing you're not an engineer? As materials science (basically chemistry and physics) has advanced over the past decades, we have learned a lot about what makes the strong ones strong, the fatigue resistant ones fatigue resistant, the creep resistant ones creep resistant, etc. We also have a better idea of the limits of material science.

You are talking about building a structure two or more orders of magnitude taller and wider than anything ever built before. There is no doubt that would take major innovations in materials science to achieve. Yet the engineers who designed the current tallest structures in the world aren't dummies. They are already using the strongest materials that are currently available, and materials that are butting up against the limits of what is physically possible.

Carbon nanotubes are promising and they may even be the breakthrough we need to make a space elevator or the type of structure you mentioned possible. I wouldn't hold my breath though.

[peadar1987]

Pffftt... Because we all know that space starts 60 miles up and that you float when you get there. Heck, some kids showed NASA a thing or two by sending a lego guy into space with a balloon. NASA. What a bunch of rocket scientists! lol

Well, if you can get a stable platform that high, it really reduces the problem of air resistance if you want to launch something using a cannon or railgun. It's building something that high that's your problem

[GoSlash27]

A space elevator is the future equivalent of a bullet train: In theory, it's the best possible solution, but in practice, it's the next thing to worthless.

Ultimately, space is about dollars spent per pound of cargo in orbit. Even if the space elevator puts cargo up there for free, you'd never get enough cargo up it to justify the R&D cost.

JMO,

-Slashy

[TeeGee]

Getting payloads up into GSO without ANY use of expendable rockets will be a massive boost in orbital access. It would thus make launches cheaper and even accessible to average folk. Sure the initial structure will be expensive (super expensive) but because it will be sooooo easy (and safer) to get payloads into orbit, companies would rather use the elevator than rockets. Rockets explode.

[GoSlash27]

Getting payloads up into GSO without ANY use of expendable rockets will be a massive boost in orbital access. It would thus make launches cheaper and even accessible to average folk. Sure the initial structure will be expensive (super expensive) but because it will be sooooo easy (and safer) to get payloads into orbit, companies would rather use the elevator than rockets. Rockets explode.

Likewise, if we were to commit to building unique roads from every building on Earth to every other building, there would never be any traffic and transportation costs would plummet.

There are concepts that are so outrageously expensive at the outset that they can never pay for themselves through use.

Regards,

-Slashy

[Everten P.]

Likewise, if we were to commit to building unique roads from every building on Earth to every other building, there would never be any traffic and transportation costs would plummet.

There are concepts that are so outrageously expensive at the outset that they can never pay for themselves through use.

Regards,

-Slashy

First, building roads between buildings is nothing like building a space elevator, space elevators are far more practical. Second there would be loads of traffic in the 24 hours after it was built and declared safe, I am sure that NASA would use this to transport goods from earth to the ISS or beyond. This would also mean ( after things calmed down ) that ships could be built in space and would become the luxury sports cars of today, also the thing would be very expensive ( as we all should know ) because the thing would have to stretch from ground level to geosynchronous orbit (as to use centripetal force to pull it from earth and make it more stable) so that means that anything built there can stay in orbit almost indefinitely so permanent colonies can be built (as to provide a human habitat) so that orbital factories and power plants have a strong workforce. All of this WILL cost LOADS of money but if that money can firmly place the human race in space then I am all for it.

P.S. Splashy don't be a party pooper by stating facts that some will agree with but most of us know

[shynung]

First, building roads between buildings is nothing like building a space elevator, space elevators are far more practical. Second there would be loads of traffic in the 24 hours after it was built and declared safe, I am sure that NASA would use this to transport goods from earth to the ISS or beyond. This would also mean ( after things calmed down ) that ships could be built in space and would become the luxury sports cars of today, also the thing would be very expensive ( as we all should know ) because the thing would have to stretch from ground level to geosynchronous orbit (as to use centripetal force to pull it from earth and make it more stable) so that means that anything built there can stay in orbit almost indefinitely so permanent colonies can be built (as to provide a human habitat) so that orbital factories and power plants have a strong workforce. All of this WILL cost LOADS of money but if that money can firmly place the human race in space then I am all for it.

That's still several big 'if's and 'maybe's. Going to GSO still needs plenty of energy, and that means constructing a major power station nearby to power the climbers (wirelessly or otherwise), or installing very powerful engines on the climbers themselves, of which I find rockets preferable.

Also, I'm not convinced that a functional space elevator will be instantly crowded when it first opened, barring visitors who wanted to see launches. There's only one space station up there, and it doesn't need a lot of supplies.

Also, I haven't seen anyone pointing out that a space elevator isn't necessarily immune from NEOs or orbital debris. If unlucky enough, a single strike from an asteroid could simply cut it in two, and wreak all kinds of havoc on both sides.

[GoSlash27]

First, building roads between buildings is nothing like building a space elevator, space elevators are far more practical. Second there would be loads of traffic in the 24 hours after it was built and declared safe, I am sure that NASA would use this to transport goods from earth to the ISS or beyond. This would also mean ( after things calmed down ) that ships could be built in space and would become the luxury sports cars of today, also the thing would be very expensive ( as we all should know ) because the thing would have to stretch from ground level to geosynchronous orbit (as to use centripetal force to pull it from earth and make it more stable) so that means that anything built there can stay in orbit almost indefinitely so permanent colonies can be built (as to provide a human habitat) so that orbital factories and power plants have a strong workforce. All of this WILL cost LOADS of money but if that money can firmly place the human race in space then I am all for it.

P.S. Splashy don't be a party pooper by stating facts that some will agree with but most of us know

Ahh, but whether or not *you* are all for it is immaterial unless *you* are going to foot the bill. You can't afford to pay for it. Even if you got together with everybody on the planet who thinks it's a neat idea and you all pooled your money, you still couldn't afford it.

What you're really talking about is forcing people who don't like this idea and think it's a waste of money to pay for it against their will.

[Everten P.]

Ahh, but whether or not *you* are all for it is immaterial unless *you* are going to foot the bill. You can't afford to pay for it. Even if you got together with everybody on the planet who thinks it's a neat idea and you all pooled your money, you still couldn't afford it.

What you're really talking about is forcing people who don't like this idea and think it's a waste of money to pay for it against their will.

Again don't be a party pooper .

Also I am not forcing anyone I am trying to persuade people towards it.

P.S. Slashy if everyone wanted to do it cost literally would not matter.

[GoSlash27]

Also I am not forcing anyone I am trying to persuade people towards it.

"Don't be a party pooper" isn't a very persuasive argument IMO. YMMV.

[Everten P.]

True. But, I never said I was trying to persuade him also I said that because everyone was coming up with good ideas and he was just "raining on the parade".

[Nibb31]

Reminding about reality isn't "raining on the parade". If all you want to do is speculate about invented pseudo-scientific technobabble, then go to a Star Trek forum.

[SciMan]

I think there are a few people here conflating "Can't pay for it", "Can't make the materials for it", and "Can't build it due to laws of physics"

It's theoretically possible to make a space elevator according to the laws of physics as we know them.

Carbon nanotubes have been calculated to have the requisite strength to make it work.

- The physics checks out, which means that the whole thing won't fly apart if it were to suddenly appear out of thin air, fully built and ready to operate.

We don't know how to make the materials in large enough lengths and/or quantities yet. CNT lengths will need to be at least several kilometers between defects, and we would need a reliable way to bond two CNT strands laying side-by-side with a bond of the same or stronger strength.

- This is an engineering challenge, which means that it CAN be solved, given enough time. How much time? I don't know. At least 100 years, possibly 1,000.

Humanity has controlled fire, invented the wheel, harnessed electricity, mastered powered flight, and plenty of other things that I'm sure were thought impossible 10 years before somebody tinkering away in their garage (or cave) got it to work the first time.

But nobody will pay for it. Heck, nobody CAN pay for it.

My own ballpark estimates that I didn't do any math for say it would take ~ 20-50% of the GDP of the top 10 countries in the world, combined, for at least 10 years.

And that's for just one elevator of marginal payload capacity. And I bet my estimates are on the cheap end for even that. Plus there's the chicken-and-egg problem of not having anything that would use that payload capacity, so there's no incentive to start building one or researching how to build one.

- This one's a sociopolitical-economical challenge. I'm not going to touch that one with a 35km carbon nanotube pole anchored to an asteroid.

Edited July 8, 2014 by SciMan

[randomness5555]

Why is everone going on about the price? Carbon nano-tubes are pricey-atm. They might be cheaper than wool in 120 years-if they are as good as we think they will be, people will work out ways to make more for less. Besides, 80 or so miles is a long way-but we've layed fibre optic cables longer than that across the sea-floor. as for who would use that-space station construction anyone? Or even, moonbases? Building one is impractical now-but if you could get every module into space for almost free? These things are usefull.

But honestly, Skylon's probably going to be the answer-cheaper than an elevator and you still get about 200 uses out of each one. And that's predicted to be ready by 2020 or so.

[shynung]

But honestly, Skylon's probably going to be the answer-cheaper than an elevator and you still get about 200 uses out of each one. And that's predicted to be ready by 2020 or so.

I really wish this statement could be true, but REL's current condition at the moment doesn't hold much promise for a mass-produced SSTO vehicle within 6 years.

[AngelLestat]

How much time? I don't know. At least 100 years, possibly 1,000

know if something can be economically viable or not depending on how efficient different approach could be, is one thing.

But make a 1000 years!!! prediction of the technological requirements needed for this purpose shows a complety lack of knowledge about the topic and how fast technology grows.

[NASAFanboy]

Will it be done? Probably. Will it be done in fifty years? Probably not. At the most optimistic "estimates" (With room for assumptions), we could build one at around 2080 at the earliest. By then, a stable network of SSTO spacecraft/reusable rockets with quick turnaround rates would render the need mostly useless, unless it was a publicity stunt, but even then, it would be mostly empty. There is a limit as to how many customers want spacecraft and things sent to orbit, all of which could be handed with a dedicated network of SSTOs and reusable rockets.

We might be able to see a stratosphere spaceport, and I believe that (Or launch loops/railguns) are a much better alternative.

[PakledHostage]

Why is everone going on about the price? Carbon nano-tubes are pricey-atm. They might be cheaper than wool in 120 years-if they are as good as we think they will be, people will work out ways to make more for less. Besides, 80 or so miles is a long way-but we've layed fibre optic cables longer than that across the sea-floor. as for who would use that-space station construction anyone? Or even, moonbases? Building one is impractical now-but if you could get every module into space for almost free? These things are usefull.

But honestly, Skylon's probably going to be the answer-cheaper than an elevator and you still get about 200 uses out of each one. And that's predicted to be ready by 2020 or so.

This is why we can't have nice things...