A Space Elevator Draft

[fusor]

Since space elevators only exist in theory, and in sci-fi, anyone's illustration is "legitimate". It used to be we had the physics of aircraft wings and how the provided lift down, from theory to practicality. Except as we learned more and understood more, the shape of a wing has changed, the materials we use have change, and our understanding of aerodynamics has changed - all because we went from theory to practicality, which created more theories which required more prototypes to prove the theory. Engineers build 1-1 scale prototypes to test theories all the time. NASA has tested space tethers since the Gemini mission era. They tested them again on a couple of shuttle flights. The tests failed, though in theory they should have worked. This tells us that our theories are not 100% translatable into reality. We still have much to learn and more theories to test.

That's an enormous oversimplification of how science and knowledge evolve. Sure, practical factors can and do affect what's theoretically possible, but that doesn't change the basic physics, which is understood here. The general consensus (as described in the links I posted) is that Space Elevators are super-strong (perhaps impossibly super-strong) cables that are dropped from orbit and connected to the ground or onto a floating platform at sea, and at the other end is a counterweight to keep the cable under tension. It's not going to be a solid structure like a building or a lattice as Shawn showed.

My point is that if anyone's going to illustrate something - even something conjectural - the least they can do is read up on the basic theory and understand how it works first, so they can create something that looks like our present understanding of it. Otherwise it's like trying to draw an aeroplane just knowing it's got a cockpit at the front and that it has wings - well great, but how many wings? where are they? what are the proportions? You might end up with some monstrosity with six sets of horizontal and vertical wings!

Some imagination is fine, but there's no need to make the whole damn thing up wholesale just because one thinks that "theoretical" means "anything goes".

 

[ShawnDriscoll]

It's not going to be a solid structure like a building or a lattice as Shawn showed.

Mine isn't solid though. Nor latticed. Stacking a 3D model is only how I made this rough draft so far. I'm working on one of the freight lifts now for it. Seeing how smooth of acceleration I can get part way up the elevator.

 

[Tenacious-Techhunter]

Note how I said “ever pitched”; as in, “by and to space agencies”. Concepts that fail to consider shear strength, tensile strength, and compression strength are unworthy of repetition. So don’t.

Changing your subject as usual. Noted.

I didn’t change anything. You simply failed to understand what I was saying.

 

[Tenacious-Techhunter]

Space elevators are theory, period. Illustrate to us how they should look. It'll just be another theory anyway. You don't role-play though, do you. You're more a board gamer, right? With tiles and all?

A theory limited by physical constraints, some of which cannot be overcome by technology, because they are limited by physics.

 

[Tenacious-Techhunter]

Since space elevators only exist in theory, and in sci-fi, anyone's illustration is "legitimate".

Nope. Has to meet all the conceptual criteria. “Rigid” is not among those criteria.

NASA has tested space tethers since the Gemini mission era. They tested them again on a couple of shuttle flights. The tests failed, though in theory they should have worked. This tells us that our theories are not 100% translatable into reality. We still have much to learn and more theories to test.

NASA has never tested “space tethers”, because the basic material limitations were simply impossible to implement at the time; they knew the math didn’t work out yet, but might in the future. Now we have carbon nanotubes, and we’ll see how that goes.

That sounds suspiciously like a circular tower, not a true cable.

Only if you think a toothed timing belt looks like a rigid doughnut...

 

[Tenacious-Techhunter]

A theory limited by physical constraints, some of which cannot be overcome by technology, because they are limited by physics.

Just like your role-play, Ryan.

That’s just about the best compliment you could have ever given me. Roleplaying limited by physical plausibility is a damn good thing that brings wisdom into what might otherwise be nothing but nonsensical antics. Your failure to insult me is highly amusing.

 

[Tenacious-Techhunter]

It's not going to be a solid structure like a building or a lattice as Shawn showed.

Mine isn't solid though. Nor latticed. Stacking a 3D model is only how I made this rough draft so far. I'm working on one of the freight lifts now for it. Seeing how smooth of acceleration I can get part way up the elevator.

That’s a laugh... you think your doodle has something to do with how a space elevator would perform...

It’s friction, drag, and gravity limited. As a car gets further away from the planet, the atmosphere gives way, and the gravitational pull drops. The friction doesn’t, though, and without the atmosphere to cool it, it’s just going to have to slow down to whatever the system can deal with.

The conceptual design has nothing to do with anything related to the performance.

 

[phavoc]

Nope. Has to meet all the conceptual criteria. “Rigid” is not among those criteria.

Right... like a aerospace engineer from 1940 looking at a super-critical wing design from 2010 and telling the modern day engineer that this wing doesn't meet design criteria.

NASA has never tested “space tethers”, because the basic material limitations were simply impossible to implement at the time; they knew the math didn’t work out yet, but might in the future. Now we have carbon nanotubes, and we’ll see how that goes.

You haven't met a fact you didn't like and tried to discredit someone have you?

Deployed as secondary payloads on GPS launches - http://www.nasa.gov/centers/marshall/pdf/337451main_Tethers_In_Space_Handbook_Section_1_2.pdf

STS-75 space electricity experiment - http://www-spof.gsfc.nasa.gov/Education/wtether.html

And hey, whaddya know, a whole Wikipedia page listing a bunch of space tether experiments, from Gemini, through the Shuttle and beyond - https://en.wikipedia.org/wiki/Space_tether_missions.

So.... please tell us again how NASA has never tested these? Early experiments didn't use carbon nanotubes. They were experiments, they used existing materials such as kevlar or other currently available materials. The biggest problem they faced (or would, with long-term exposure) is that objects in low-earth orbit degrade faster due to things like UV exposure, atomic oxygen, ionizing radiation, etc. In fact, NASA experimented with this, too. Now please tell me NASA never deployed the Long Duration Exposure Facility. Carbon nanotubes should not have these same issues. However, until we have more experiments to prove out these theories, we don't truly know.

Only if you think a toothed timing belt looks like a rigid doughnut...

Hrm, based on your current track record with "facts".... please show me a toothed timing belt with six channels allowing independent up/down movement on aforementioned timing belt. No? I think I will stick with my original statement.

 

[phavoc]

Since space elevators only exist in theory, and in sci-fi, anyone's illustration is "legitimate". It used to be we had the physics of aircraft wings and how the provided lift down, from theory to practicality. Except as we learned more and understood more, the shape of a wing has changed, the materials we use have change, and our understanding of aerodynamics has changed - all because we went from theory to practicality, which created more theories which required more prototypes to prove the theory. Engineers build 1-1 scale prototypes to test theories all the time. NASA has tested space tethers since the Gemini mission era. They tested them again on a couple of shuttle flights. The tests failed, though in theory they should have worked. This tells us that our theories are not 100% translatable into reality. We still have much to learn and more theories to test.

That's an enormous oversimplification of how science and knowledge evolve. Sure, practical factors can and do affect what's theoretically possible, but that doesn't change the basic physics, which is understood here. The general consensus (as described in the links I posted) is that Space Elevators are super-strong (perhaps impossibly super-strong) cables that are dropped from orbit and connected to the ground or onto a floating platform at sea, and at the other end is a counterweight to keep the cable under tension. It's not going to be a solid structure like a building or a lattice as Shawn showed.

My point is that if anyone's going to illustrate something - even something conjectural - the least they can do is read up on the basic theory and understand how it works first, so they can create something that looks like our present understanding of it. Otherwise it's like trying to draw an aeroplane just knowing it's got a cockpit at the front and that it has wings - well great, but how many wings? where are they? what are the proportions? You might end up with some monstrosity with six sets of horizontal and vertical wings!

Some imagination is fine, but there's no need to make the whole damn thing up wholesale just because one thinks that "theoretical" means "anything goes".

Of course it's an oversimplification, I'm not getting paid to write a formal paper, I'm not submitting it for my doctoral thesis, and this IS a sci-fi gaming board. But nothing I said was incorrect. It actually IS how science works, even if the terminology and process is simplified. Many engineers subscribe to the KISS (keep it simple stupid) whenever possible because simple is good. If you ask an engineer to draw an airplane, I'm pretty sure you will get the same image as asking a 6yr old to draw one, except instead of crayons he may use a CAD program, or a .5mm mechanical pencil. However, if you asked the same pair to DESIGN an airplane, that's where the engineer would ask you a bunch of questions, and the 6yr old would probably give you the same picture. These are two related, but not not always linked concepts.

From the illustration that Shawn initially provided, it was a hexagonal affair, with cross connections. No particular scale was given or could be extrapolated from the image. It would be easy enough to have each one of the hexagonal anchor points be it's own cable, and the entire affair is strengthened with cross connectors. It is entirely possible to build a tower-like structure that moves like a cable - especially since you have an orbital anchor that keeps tension on the entire structure. We don't have that capability today with buildings, but even the tallest, most "rigid" buildings we build actually sway at the top. There's an entire sub-set of engineering principles that had to be created to help counter-act the swaying (they are called mass dampers). I forget which building in Chicago has it, but it's mass damper is a just a giant block of steel that is set on top of a liquid and as the building shifts one way, it shifts the other. It's very simple, but very neat.

 

[Condottiere]

Gamewise, what's the material being used, what's it's tech level of introduction, and which planets have an elevator?

It could be string theory.

 

[fusor]

Deployed as secondary payloads on GPS launches - http://www.nasa.gov/centers/marshall/pdf/337451main_Tethers_In_Space_Handbook_Section_1_2.pdf

STS-75 space electricity experiment - http://www-spof.gsfc.nasa.gov/Education/wtether.html

And hey, whaddya know, a whole Wikipedia page listing a bunch of space tether experiments, from Gemini, through the Shuttle and beyond - https://en.wikipedia.org/wiki/Space_tether_missions.

Just as a point, "space tethers" aren't remotely the same as "beanstalks". Those experiments were to test whether a line trailing behind an orbiting craft could be used to generate power by trailing through the earth's magnetic field. They're a totally different thing from what's required for a beanstalk - it's like comparing a washing line to a transmission line cable (yes, they're both thin, linear, and flexible, but used for entirely different purposes).

 

[phavoc]

Deployed as secondary payloads on GPS launches - http://www.nasa.gov/centers/marshall/pdf/337451main_Tethers_In_Space_Handbook_Section_1_2.pdf

STS-75 space electricity experiment - http://www-spof.gsfc.nasa.gov/Education/wtether.html

And hey, whaddya know, a whole Wikipedia page listing a bunch of space tether experiments, from Gemini, through the Shuttle and beyond - https://en.wikipedia.org/wiki/Space_tether_missions.

Just as a point, "space tethers" aren't remotely the same as "beanstalks". Those experiments were to test whether a line trailing behind an orbiting craft could be used to generate power by trailing through the earth's magnetic field. They're a totally different thing from what's required for a beanstalk - it's like comparing a washing line to a transmission line cable (yes, they're both thin, linear, and flexible, but used for entirely different purposes).

For that particular experiment, yes, the satellite was trailed behind the shuttle in an attempt to measure electromagnetic charge. It also broke, and a $400 million dollar satellite became space junk. Tethers have been used for that as well as experimenting with energy transfer. That experiment was actually helpful because even though it failed they were able to learn more about materials and tethering operations.

Some models call for the space tether/elevator/beanstalk to be built in orbit and then down into the atmosphere. But at this point any data they can get through experiments is invaluable.

 

[phavoc]

Deployed as secondary payloads on GPS launches - http://www.nasa.gov/centers/marshall/pdf/337451main_Tethers_In_Space_Handbook_Section_1_2.pdf

STS-75 space electricity experiment - http://www-spof.gsfc.nasa.gov/Education/wtether.html

And hey, whaddya know, a whole Wikipedia page listing a bunch of space tether experiments, from Gemini, through the Shuttle and beyond - https://en.wikipedia.org/wiki/Space_tether_missions.

Just as a point, "space tethers" aren't remotely the same as "beanstalks". Those experiments were to test whether a line trailing behind an orbiting craft could be used to generate power by trailing through the earth's magnetic field. They're a totally different thing from what's required for a beanstalk - it's like comparing a washing line to a transmission line cable (yes, they're both thin, linear, and flexible, but used for entirely different purposes).

For that particular experiment (STS-75), yes, the satellite was trailed behind the shuttle in an attempt to measure electromagnetic charge. It also broke, and a $400 million dollar satellite became space junk. Tethers have been used for that as well as experimenting with energy transfer. That experiment was actually helpful because even though it failed they were able to learn more about materials and tethering operations. And as an FYI, not all of the tether experiments were the same. The thing they all had in common WAS a tether. But they have done experiments using the theoretical orbital transfer mechanics.

Some models call for the space tether/elevator/beanstalk to be built in orbit and then down into the atmosphere. But at this point any data they can get through experiments is invaluable.

 

[fusor]

Some models call for the space tether/elevator/beanstalk to be built in orbit and then down into the atmosphere. But at this point any data they can get through experiments is invaluable.

Either way, a tether is still not a beanstalk and therefore is not a valid comparison.

But it seems people here just want to say "screw science, we know better". So whatever, do what you like.

 

[phavoc]

Some models call for the space tether/elevator/beanstalk to be built in orbit and then down into the atmosphere. But at this point any data they can get through experiments is invaluable.

Either way, a tether is still not a beanstalk and therefore is not a valid comparison.

But it seems people here just want to say "screw science, we know better". So whatever, do what you like.

Well, you can complain all you want, but "space tether" is equated to "beanstalk", or "space elevator". If you prefer, from the Wiki entry on "space elevator" -

A space elevator is a proposed type of space transportation system.[1] The main component would be a cable (also called a tether) anchored to the surface and extending into space.

You make not like the semantics being used, but you are in the minority and the literature out there doesn't support your position. Which literature you ask? Popular Mechanics refers to the cable as a "tether". The aforementioned Wikipedia article refers to it as a cable or "tether". The IEEE Spectrum magazine says, "The idea of a space elevator has been around for over a century. The basic concept is simple: a tether descends from a spacecraft in geostationary orbit to a floating platform at the equator, probably in the eastern Pacific Ocean. Because of a counterweight that would extend far into space, the space elevator’s tether would be gravitationally stable, allowing electric elevator cars to make the week-long climb to orbit powered by solar panels and ground-based lasers."


Tether, tether, tether...

Now, you were saying?

 

[fusor]

Now, you were saying?

Good grief, do I have to explain this as if you were five years old? "tether" is a generic word (technically it means "a rope, chain, or the like, by which an animal is fastened to a fixed object so as to limit its range of movement.", so really it shouldn't be used here at all) - but "Space elevator" is a specific concept. Sure, they're all "tethers" (or cables, or whatever you want to call them) but all tethers are not the same. A Space Elevator "tether" has to be made of much stronger stuff than one being trailed behind a satellite to generate power.

Is that really so hard for you to grasp or are you just being deliberately argumentative here?

 

[phavoc]

Now, you were saying?

Good grief, do I have to explain this as if you were five years old? "tether" is a generic word (technically it means "a rope, chain, or the like, by which an animal is fastened to a fixed object so as to limit its range of movement.", so really it shouldn't be used here at all) - but "Space elevator" is a specific concept. Sure, they're all "tethers" (or cables, or whatever you want to call them) but all tethers are not the same. A Space Elevator "tether" has to be made of much stronger stuff than one being trailed behind a satellite to generate power.

Is that really so hard for you to grasp or are you just being deliberately argumentative here?

I'm not the one trying to correct everybody else. You pointed out tether wasn't the right term. I pointed out that the literature out there says you are incorrect on that statement. By default a space elevator / beanstalk / space tether is going to have to be made out of much stronger stuff than virtually everything. However carbon nanotubes work equally well as tethers for trailing objects as well as building material for a space elevator. Why? Because of carbon nanotubes amazing physical properties. For what it's worth, a beanstalk is also a generic term, and it refers to a plant, and in the context of a space elevator it was adapted from a children's fairy tale. The English language is full of words with multiple meanings. But did you see me trying to be argumentative with your use of the term? No, because it's an acceptable alternative in the literature and discussions being had.

You are trying to defend your viewpoint by offering nothing in return. You have not cited any facts in your rebuttal (for instance a Canadian company has an actual patent on a 12mile space elevator. Did you even know that?) You continue to try (and fail) to attack others positions and statements by trying to split hairs and not actually addressing the question (which, by the way, was directed towards TT who incorrectly said NASA had never done any space experiments with tethers).

I was defending Shawn him here because he isn't terribly off base with what he's putting out there. The 52nd century is theoretical. Space elevators are theoretical. This entire game is theoretical and its supposed to be fun and entertaining and all that jazz. When we get a working space elevator or three, then sure, you can correct people all you want based on facts. But since we've not reached that point, everything is conjectural. His illustrations aren't terribly different than others that have come before him.

I don't think I'm being argumentative at all (at least not in a negative connotation). However I do think it's only fair to the OP that he be defended here for the reasons I've pointed out. As well as correcting opinion statements that are trying to be passed off as accepted facts.

 

[FallingPhoenix]

But it seems people here just want to say "screw science, we know better". So whatever, do what you like.

Or maybe they just want to not require a degree in physics (or chemistry or biology) or to be 100% up-to-date on current scientific theory concerning space elevators before they try to make a cool picture or play their science fiction RPG.

So maybe if we said "That's a pretty sweet picture, if you're interested, here's some cool information on space elevators that I really like and might help your concept" and then let it go, it would inspire people to want to learn more.

And maybe in a science fiction RPG, there's room for both people who like their SF extrapolations conservative and those who like them more revolutionary. And maybe there's even room for people who want to use Traveller rules to play Star Wars.

 

[fusor]

So maybe if we said "That's a pretty sweet picture, if you're interested, here's some cool information on space elevators that I really like and might help your concept" and then let it go, it would inspire people to want to learn more.

That's exactly what I did. And then people who have no understanding of the subject and who think that "theoretical" means that they can make up any old bullshit started making excuses and claiming that they knew better than scientists.

But whatever. Do whatever the hell you want.

 

[FallingPhoenix]

So maybe if we said "That's a pretty sweet picture, if you're interested, here's some cool information on space elevators that I really like and might help your concept" and then let it go, it would inspire people to want to learn more.

That's exactly what I did.

Ah, you're right. I got caught up in the arguments and forgot that. I'm sorry.