US Dollar Faces Collapse In 24 Months

[Kulindahr]

No one has said the concept is nuts. The concept has merit and certainly deserves further research and investment.

However the current cost of getting to orbit puts a prohibitively expensive price on any kind of thing like this in the current economic climate.

None of these ideas are going to reduce the deficit, they will all require substantially more money going to space exploration than we currently spend.

Given a space elevator, chasing asteroids would be cheap. But designing, building, and launching probes would be worth the effort; one could be built to ride up in a shuttle bay.

Except we don't have a shuttle any more.


Ironically, a team designed a spinner for the lead line of a space elevator -- in several pieces each meant to go up as a shuttle load.

For the moment, we're going to have to rely on private enterprise to pursue this. My concern is simple: if private enterprise builds a space elevator, they will own the Solar System; owning the Solar System, they will effectively own Earth.

Now: picture the current Republic leadership, allied with the Koch brothers, in charge of such a thing.

I'd rather see the U.S. government (actually, the three North American governments) do this, and issue shares of stock to all citizens... not allowed to be sold (inherited, maybe). When that second asteroid comes back, two-thirds the value is paid out as dividends (do the arithmetic -- $14 trillion divided by 550 million....).

 

[hotatlboi]

In terms of physics and construction technique, it's a suspension bridge

Totally FALSE.

The physics and construction techniques of a space elevator are totally different from that of a suspension bridge.

The only similarity is that gravity aids both of them. Pretty much everything else is simply not applicable in anywhere near the same way. You have a huge number of additional considerations with a space elevator.

And that's the point! A suspension bridge made of jungle vines, of cotton clothesline, of hemp rope, of steel cable -- they're all the same thing. The materials don't matter

They matter if NONE of those materials will work for what you want to build!

only the equations matter

The equations that need to be analyzed and designed around to construct a space elevator are far more complex than those of a suspension bridge. That's what I'm trying to get you to realize.

Yet the cables for a space elevator will be very, very much like old hemp ropes: fibers bound by friction and possibly some matrix are spun into and hold together as thread

Once we can actually make a long thread of the needed material, then sure we can wind it into a cord. We can't do that yet.

 

[hotatlboi]

Given a space elevator

Good grief, this isn't going to be a given anytime in the next few decades.

 

[Kulindahr]

None of these ideas are going to reduce the deficit, they will all require substantially more money going to space exploration than we currently spend.

Note: I didn't say reduce the deficit; I said pay off the debt.

Though if the Mad Hatters of the Tea Party have their way, and the dollar collapses, the space elevator will probably be built be Brazil, and we can learn to speak Portuguese if we want to advance in the world.

 

[Kulindahr]

Good grief, this isn't going to be a given anytime in the next few decades.

You lost me this time.

 

[JB3]

No it isn't. That's laughable.

The 787 contains huge similarities to a bunch of other implementations of existing technology that is proven (other airplanes).

A space elevator is a radical new idea with nothing remotely parallel currently in existence.

Nope. There's nothing remotely similar out there. The manufacturing process (which is where the difficulty has been) is unlike anything any aerospace company has ever done before.

 

[hotatlboi]

Nope. There's nothing remotely similar out there.

Sure there is. The basic principles of its design and what you need to consider (a fixed wing aircraft traveling through air, generating lift, producing thrust) has been done for decades.

There might not be any remotely similar airplanes out there in terms of what features or capabilities it has, but it's still an airplane. That means the basic feasibility of how the device will operate has been worked out. That is not the case with a space elevator.

The two are not even close to in the same category of being revolutionary.

A space elevator will revolutionize access to space and drop the costs by several orders of magnitude. No such quantum leap in aviation will result from the 787.

 

[JB3]

Sure there is. The basic principles of its design and what you need to consider (a fixed wing aircraft traveling through air, generating lift, producing thrust) has been done for decades.

Do you even know anything about the 787? Its a rethinking of the entire concept of modern aviation engineering and design. The only thing it shares with current aircraft are its shape, and even that's been altered quite a bit.

The very fact that you think that just because its an aircraft that looks like other aircraft it isn't revolutionary, shows that you don't know much at all about the subject.

Oh, and the 787 was ALREADY a quantum leap for aviation, even though it hasn't seen a single mile of commercial service yet. From the outset it was an aircraft designed with two things in mind, one of which has never been a priority; range, and fuel-efficiency. The very fact that it was designed from the outset to be the most efficient commercial airliner available IS a quantum leap.

 

[hotatlboi]

The only thing it shares with current aircraft are its shape, and even that's been altered quite a bit.

False, it shares what I just told you. It is a fixed wing aircraft, that travels through air, generates lift, and produces thrust. All of the common things that make a modern airplane what it is are still the same.

The main advancements are in materials (which will increase fuel efficiency).

The very fact that you think that just because its an aircraft that looks like other aircraft it isn't revolutionary, shows that you don't know much at all about the subject.

Nice try but fail. I minored in aerospace engineering in college. I can tell you what mathematical expression quantifies the lift generated over a wing from the pressure difference. The 787 does not differ in it's fundamental mode of operation in that regard.

And I never said it wasn't revolutionary. I said it's not even close to as revolutionary as a space elevator would be.

The 787 (even being a big step forward) will not reduce the cost of flying by a factor of 100 or lead to a total change in the basic principles of how people fly, or create an entire new industry. A space elevator will do all those for space access.

 

[Kulindahr]

Totally FALSE.

The physics and construction techniques of a space elevator are totally different from that of a suspension bridge.

The only similarity is that gravity aids both of them. Pretty much everything else is simply not applicable in anywhere near the same way. You have a huge number of additional considerations with a space elevator.

We did this in physics class at OSU: you do the equations for the space elevator, show it to an engineer, and they say, "Oh, a suspension bridge".

Though if you do like some proposals have and don't just balance it but put serious tension on it (like the engineer in Seattle who wants to run it out to 100,000k!), it stops being a suspension bridge so much and becomes a tether.... (somewhere in the Wikipedia archives is a discussion/argument that I sparked, over when it stops being a suspension bridge and becomes a tether; I say it's not especially relevant because for construction purposes it's a suspension bridge, and only after that can you make it a tether).

BTW, gravity in the standard suspension bridge is replaced by rotation forces in a "space bridge" (which is what engineers called it, thinking in engineering terms, but that made no sense to anyone else).

The only considerations are the standard variables -- length, strength of materials, etc.

They matter if NONE of those materials will work for what you want to build!

No, they don't -- those are just arithmetic in the equation. The only difference is that those numbers aren't big enough. The Golden Gate was the same engineering proposition in terms of the equations that a rope bridge in the Himalayas was. The materials are irrelevant to the equations.

The equations that need to be analyzed and designed around to construct a space elevator are far more complex than those of a suspension bridge. That's what I'm trying to get you to realize.

Tension? same
Harmonics? same
Aerodynamics? same, excepted integrated across a varying medium

If the equations are vastly different, it seems odd to me that none of the actual engineers and physicists and such in the forums where I've lurked have ever said so. The only areas I've seen complexity are the ones for aerodynamics, which isn't complex if you take it in stages and use a smoothing function, and torsion, where the equations apply but the results head for infinityville because of the length of the darned thing, so the big consideration is preventing torsion in the atmosphere.

Once we can actually make a long thread of the needed material, then sure we can wind it into a cord. We can't do that yet.

SO what if we can't do that yet? That's what the researchers are for. Once they have it, people have already designed the machines -- wouldn't surprise me if someone hasn't built some already, for testing.

I agree with one of the groups of investors: the moment the material for the cable is in hand, this will go up, and go up fast. I want to see the U.S. push it because I don't want to see the Koch brothers and some Russian billionaires dividing up the solar system and proceeding to dictate to governments.

 

[Kulindahr]

False, it shares what I just told you. It is a fixed wing aircraft, that travels through air, generates lift, and produces thrust. All of the common things that make a modern airplane what it is are still the same.

The main advancements are in materials (which will increase fuel efficiency).

Same thing for the space elevator. In fact, the biggest change is basically the same for both: materials manufacture.

The 787 (even being a big step forward) will not reduce the cost of flying by a factor of 100 or lead to a total change in the basic principles of how people fly, or create an entire new industry. A space elevator will do all those for space access.

And that's relevant why? That doesn't make it revolutionary as a structure, it means the structure has revolutionary effects. That's not relevant to the engineering problem.

 

[hotatlboi]

Tension? same
Harmonics? same
Aerodynamics? same, excepted integrated across a varying medium

If the equations are vastly different, it seems odd to me that none of the actual engineers and physicists and such in the forums where I've lurked have ever said so. The only areas I've seen complexity are the ones for aerodynamics, which isn't complex if you take it in stages and use a smoothing function, and torsion, where the equations apply but the results head for infinityville because of the length of the darned thing, so the big consideration is preventing torsion in the atmosphere.

Here are some of the different things you have to consider with a space elevator.

1. you have to calculate the lift you want to be able to achieve compared to the what counterweight mass gives you
2. you have to consider the effects of parasitic drag on the parts in the atmosphere
3. you have to consider the irregular shape of the earth, assuming that it would be put at the equator (the earth not being a perfect sphere)
4. you have to consider the effects of collisions with objects moving at high speed
5. you have to consider the power of the lifting body that will raise things on it
6. you have to consider the gravitational influence of the moon
7. you have to work out whether a fixed or mobile anchor point makes the most sense for reducing flex and strain on the cable
8. you have to work out how to keep the weight being added to the cable synchronous on both ends during the construction
9. you have to analyze all of the physical properties of the cable and their behavior in space (given that it will be an exotic new material)

etc etc

You do not have to consider the physics of any of these things building a suspension bridge.

You are correct that some of the equations for determining the tension on the cable would be the same as those used in suspension bridge construction. But there is far more to consider than just that.

 

[andysayshi]

To be fair, the cost of the 17 manned Apollo flights, adjusted to 2005 dollars, was around $170 billion. This returned around 350 kilograms (800 pounds) of lunar rock.

I suspect the cost of shipping millions of tons of minerals from outside the atmosphere would be in the multiple trillions of dollars.

 

[hotatlboi]

Same thing for the space elevator. In fact, the biggest change is basically the same for both: materials manufacture.

No it is not. I can't possibly understand why you would say this.

A space elevator is an entirely new mode of operation than has ever been attempted before. We know far too little about the basic principles of its operation and the effect on the needed materials to even attempt building one at this point. That is not the case for aircraft/the 787. We need further research before attempting the space elevator. It is not the same thing. Materials is the long pole in the space elevator development, but it is not the only thing needed.

That doesn't make it revolutionary as a structure

A space elevator would be FAR more revolutionary as a structure than the 787. It would likely be the most advanced structure humanity has ever built, certainly the most advanced in the field of transportation.

 

[Kulindahr]

Here are some of the different things you have to consider with a space elevator.

1. you have to calculate the lift you want to be able to achieve compared to the what counterweight mass gives you
2. you have to consider the effects of parasitic drag on the parts in the atmosphere
3. you have to consider the irregular shape of the earth, assuming that it would be put at the equator (the earth not being a perfect sphere)
4. you have to consider the effects of collisions with objects moving at high speed
5. you have to consider the power of the lifting body that will raise things on it
6. you have to consider the gravitational influence of the moon
7. you have to work out whether a fixed or mobile anchor point makes the most sense for reducing flex and strain on the cable
8. you have to work out how to keep the weight being added to the cable synchronous on both ends during the construction
9. you have to analyze all of the physical properties of the cable and their behavior in space (given that it will be an exotic new material)

etc etc

You do not have to consider the physics of any of these things building a suspension bridge.

Some of those have been dealt with already. If I wanted to hunt archives, I could find papers on 1, 2, 3, 5, and 8 -- I've read the summaries.

7 is really part of 9.

But suspension bridge cables suffer from atmospheric wear (just ask the guys at the Golden Gate), and have to deal with the stress of bearing moving loads (and I don't mean the loon who tried riding a motorcycle on a suspension bridge cable -- too bad that was before YouTube).

4 I've read so much on it's boggling -- it's considered more important than designing a ground station, by many. The favorite idea seems to be a "laser fan", an array of multiple beams which would "brush" objects away by inducing propulsion-yielding ablation on the face opposite a direction that would move the object away from the cable. More wild enthusiasm is generated by ideas for implementing "Star "Wars" toys to blast or vaporize things -- including an adaptation of a rail gun that would be safe because its projectiles would burn up in the atmosphere, making it effectively a plasma gun, because what hit the unwanted object would be a little and rapidly-expanding cloud of plasma (caveat: targeting systems), which someone came up with after many others pointed out that shooting at things with 10c bolts would leave any that missed falling somewhere.

6 is the most interesting because I'm not sure I've ever even seen it. Sadly, my math skills have deteriorated to the point I can't quickly work out just how much stress that could cause.

Although the reverse is incredibly important: the Earth's gravity on things near the Moon is such that the materials we have now are sufficient for such an elevator on the far side, but not quite good enough for one on the near side.

You are correct that some of the equations for determining the tension on the cable would be the same as those used in suspension bridge construction. But there is far more to consider than just that.

As my sister-in-law's grad prof in materials was fond of saying, "The rest is details -- that's why there are techs".


And multiple million$ are being spent learning many of these things and dealing with them. There's even a group that wants to build a giant dirigible-like flying platform that would "station-keep" above a point on the ground, slowly ascending, to test various materials, especially proposed protective ones; there's another that says they can build a tower twelve klicks tall, and are trying to get support to pay for it; they want to use the altitude to test materials also. The people with the flying platform get my vote, because it would also serve to test the idea of sky cities associated with the cable (or independent)... besides obvious reasons.

 

[Kulindahr]

To be fair, the cost of the 17 manned Apollo flights, adjusted to 2005 dollars, was around $170 billion. This returned around 350 kilograms (800 pounds) of lunar rock.

I suspect the cost of shipping millions of tons of minerals from outside the atmosphere would be in the multiple trillions of dollars.

And given the number of hours of TV coverage Americans watched, it was the best investment in public entertainment ever, at about a tenth the price of a ticket at a movie theater.

 

[hotatlboi]

Some of those have been dealt with already. If I wanted to hunt archives, I could find papers on 1, 2, 3, 5, and 8 -- I've read the summaries.

That was by far not an exhaustive list. There's plenty more. For example, you have to consider that the local gravitational field is different at every point along the cable, not the case for suspension bridge cables (within the margin that matters).

The point I was just trying to make was that your "all the same equations will be used" idea is just not the case.

But suspension bridge cables suffer from atmospheric wear

At sea level yes. For the space elevator you have to consider the effects at high altitude and also the effects of radiation that does not penetrate the lower atmosphere.

I've read so much on it's boggling -- it's considered more important than designing a ground station, by many. The favorite idea seems to be a "laser fan", an array of multiple beams which would "brush" objects away by inducing propulsion-yielding ablation on the face opposite a direction that would move the object away from the cable. More wild enthusiasm is generated by ideas for implementing "Star "Wars" toys to blast or vaporize things -- including an adaptation of a rail gun that would be safe because its projectiles would burn up in the atmosphere, making it effectively a plasma gun, because what hit the unwanted object would be a little and rapidly-expanding cloud of plasma (caveat: targeting systems), which someone came up with after many others pointed out that shooting at things with 10c bolts would leave any that missed falling somewhere.

We're not just dealing with large objects here. We have to know how it will react to small micrometeroids and things like that. We can not "zap" all those by any method.

6 is the most interesting because I'm not sure I've ever even seen it. Sadly, my math skills have deteriorated to the point I can't quickly work out just how much stress that could cause.

What it causes is a shearing force along the cable when the moon's gravitational pull is off-axis with the cable.

Although the reverse is incredibly important: the Earth's gravity on things near the Moon is such that the materials we have now are sufficient for such an elevator on the far side, but not quite good enough for one on the near side.

That is true but I don't see how it is incredibly important as it doesn't get us anything. We have no pressing need to reduce the launch costs from the moon to space, since there is no market for launches from the moon to space at present. What we do need is to reduce the costs to launch from earth.

And multiple million$ are being spent learning many of these things and dealing with them.

And that should continue. I am all for research on this, I just do not see it as anywhere near feasible at present.

 

[Kulindahr]

That is true but I don't see how it is incredibly important as it doesn't get us anything. We have no pressing need to reduce the launch costs from the moon to space, since there is no market for launches from the moon to space at present. What we do need is to reduce the costs to launch from earth.

The talk is of returning to the moon. That means getting down, and getting back off. An elevator would make both MUCH cheaper.
Besides which, building one on the Moon would be good practice for one on Earth, with fewer things to worry about (like space debris).

Oh -- depending how micro you want to talk, there are varying levels of confidence that using some of the toys Reagan prompted we could zap anything down to half the diameter of a BB. The problem with smaller things is seeing them in time.

I cracked up when I once read a proposal for "space buoys" in a column "ahead" of the space elevator, to zap everything with. I commented that if we could do that, we wouldn't need a space elevator.....

Much better was a scheme to hang a literal shield on the cable, with ablative armor. But then we're talking non-structural mass many times greater than the cable itself.

And that should continue. I am all for research on this, I just do not see it as anywhere near feasible at present.

I think we're arguing different definitions of "feasible".

 

[JB3]

False, it shares what I just told you. It is a fixed wing aircraft, that travels through air, generates lift, and produces thrust. All of the common things that make a modern airplane what it is are still the same.

The main advancements are in materials (which will increase fuel efficiency).

Which has what, exactly to do with what I was talking about? I wasn't talking about the fact that it was an aircraft, I was talking about how it was manufactured and how revolutionary that was.

Nice try but fail. I minored in aerospace engineering in college. I can tell you what mathematical expression quantifies the lift generated over a wing from the pressure difference. The 787 does not differ in it's fundamental mode of operation in that regard.

And I never said it wasn't revolutionary. I said it's not even close to as revolutionary as a space elevator would be.

Actually, the 787 does differ somewhat, thanks to its curved wing design. But again, that's neither here nor there because it has absolutely nothing to do with what I was talking about.

 

[hotatlboi]

Which has what, exactly to do with what I was talking about? I wasn't talking about the fact that it was an aircraft, I was talking about how it was manufactured and how revolutionary that was.

I know and I was saying that in no way is it as revolutionary as a space elevator would be.

Actually, the 787 does differ somewhat, thanks to its curved wing design.

It doesn't differ from the basic understanding that I stated. Wing shape varies the lift profile yes, but that builds on a solid knowledge and understanding of how you generate lift on a fixed wing aircraft. It is a variation on a proven concept. A space elevator is a totally new concept entirely.