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Space Elevator

There aren't going to be significant induced current in a space elevator, for the simple reason that it's stationary with respect to the earth's magnetic field. There will be a modest current caused by the fact that it reaches into the ionosphere, but the current does not appear to be particularly large.
 
er doesn't the magnetoshpere change position? So even thought the wire is geostationary, the magnetic field it sits in shifts. ya? nein?
 
Hi,

AFAIK the magnetic field constantly changes shape, mainly caused by different solar wind intensities.

On the other hand, it is shaped by this wind and streches farther out on the "shadow" side of the earth. And earth spins, but the rough assymetrical field shape stays.

Furthermore there are highly frequent changes of earths magnetic field withhin seconds or days, caused by inner earth flow variations.

As I found no quantitative data regarding these effects I do not dare to say something about induced current in the beanstalk


If we got some more data, we could do that.

Regards,

Mert
 
Hello.
Jusy an idea but if the ring around the planet was built and three beanstalks where built that would give you the return circuit.
Your aerial dosnt generate current it receives it the same way as the transisters do with an EMP, its the voltage difference between the two ends or across the junction in a transister or IC.
I would have thought one of the problems with a beanstalk would be lightning.
Bye.
 
It's dependent on one major breakthrough: high-quality long-strand nanotubes at reasonable costs. We have no idea when (or if) that will be the case.
 
To incorporate space elevators into CT, I'd make them TL9 (or TL10-11 for a more conservative approach), and add them to the world generation system in a way similar to bases: Roll 10+ for an elevator to be present, DM+2 if Starport-A, DM-2 if Starport-B, DM+4 if POP 7+; don't roll if TL8-; don't roll if Starport C-; don't roll if a Poor world. A successful roll adds a "trade code" of SE (Space Elevator).

The effect is mostly flavor - you'll dock with the highport and go down the 'stalk rather than land, and the downport won't accept starships but will be the downside terminal of the stalk.
 
Methinks tis more than just cosmetic. It has lots of adventure hook potential - the difference between shuttling down to the surface, taking the PCs ship down to the downport, or taking a beanstalk could give quite different sorts of adventure possibilities.

If the trip down in a beanstalk takes some time, you could setup "Murder on the Orient Express" types of scenarios aboard the beanstalk capsule train. You could have terrorism threats against the beanstalks. You could have strikes that suddenly paralyze the entire freight moving capacity (or most of it) of a place that makes heavy use of the beanstalk to do orbit-ground-orbit cargo moving. Lots of good options.

I like your idea of making it part of the generation system. I do think that if you've got 'advanced system details" that you should probably factor in the gravity of the world. High grav worlds would (I think... correct me if someone knows different...) have less likelihood of having a beanstalk due to the additional strain on the materials of the stalk. Perhaps something like -1 to the roll for every 0.5 Gs over 1.50 Gs of local gravity.
 
On the topic of elevators--- the materials requirements aren't nearly as high if you go for a Skyhook. And Straybow, based on our current understanding of physics, I would think that a Space Elevator/Beanstalk is much more likely to happen before gravitics. :D

Back to the thread--- adding it to the existing system/world generation system is a cool idea- it would be interesting especially in the context of a HEPLaR universe (or other extremely high energy reaction drive). Additionally, with the Megatons of traffic that are supposed to be coming to and from some of the worlds in the Imperium on a daily basis, one would think you might want to go with a beanstalk simply to avoid atmospheric heating...
 
I don't think space elevators stand a chance with the current assumptions of Traveller technology. Remember we get 1-G maneuver drives at TL7. One could basically make a space ship using a TL7 fission reactor and a TL7 reactionless 1-G maneuver drive. No one would bother to build a space elevator, as that would solve a problem that doesn't exist in the Traveller Universe.

On the other hand one could assume a different TL7. Perhaps by converting some of the technology from Transhuman space to Traveller. that contains a number of reaction space drives that need help getting off the ground, there a space elevator would be quite useful, especially where their aren't multiple G drives that aren't chemically propelled.
 
Guess the "different TL 7" is a good aspect. Just notice the good old World Builders Handbook / Grand Survey / Grand Census. Those gave a pretty good insight about the detail TLs. So a society might have serious problems with gravitics, but is maybe very keen in architecture and material technology.
But generally, I agree, there are not many technological reasons to use a beanstalk.
Perhaps one of those reasons might be unusual athmospheric conditions, making regular travel to orbit hazardous.
Or think of environmental protection. A government might have banned non zero emission athmosspheric flight completely. (e.g. an ongoing athmosperic terraforming process..)
There might be a bunch of other political reasons to set up something like a beanstalk, too (migration control, trade control, biohazard control, etc...).

regards,

Mert
 
I often have to remind myself that technological 'can-do' does not always result in 'will-do'. There may be reasons quite independent of technology for the use of space elevators. They would also be an excellent way of controlling traffic flow. If a planet forbids any landings by ships and funnels everything through its beanstalks, it creates a marvellous source of revenue.

Not to mention the people-monitoring advantages for those worlds which are more concerned with their inhabitant's 'welfare' ...
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just for you to know the actual discussion:

The space elevator: going down?
Study shows that proposed carbon nanotube cables won't hold up.

Is it possible to make a cable for a space elevator out of carbon nanotubes? Not anytime soon, if ever, says Nicola Pugno of the Polytechnic of Turin, Italy. Pugno's calculations show that inevitable defects in the nanotubes mean that such a cable simply wouldn't be strong enough.
The idea of a space elevator was popularized in science fiction, where writers envisioned a 100,000-kilometre-long cable stretching straight up from the Earth's surface and fixed in a geosynchronous orbit. Payloads, or tourists, would simply ascend the cable into low-Earth orbit, eliminating the need for rocket launches.
When carbon nanotubes were discovered to have an incredibly high strength-to-weight ratio, researchers hoped they would take the idea out of fiction and bring it into reality.
But Pugno argues that atomic-scale defects in the nanotubes would reduce the strength of such a giant cable by at least 70%.

Space ribbon

Researchers think that the best shape for a space-elevator cable would be a ribbon, about a metre wide and as thin as paper. It would need to withstand at least 62 gigapascals (GPa) of tension. That's about as much as in the rope of a tug-of-war with more than 100,000 people on each side.
Laboratory tests have shown that individual nanotubes can withstand an average of about 100 GPa, an unusual strength that comes courtesy of their crystalline structure. But if a nanotube is missing just one carbon atom, this can reduce its strength by as much as 30%. And a bulk material made from such tubes is even weaker. Most fibres made from nanotubes have so far had a strength much lower than 1 GPa.
Recent measurements of high-quality nanotubes have found them to be missing one carbon atom out of every 1012 bonds; that's about one defect over 4 micrometres of nanotube length1. Defects of two or more missing atoms are much more rare, but Pugno points out that on the scale of the space elevator they become statistically probable.
Using a mathematical model that he has devised himself, and which has been tested by predicting the strength of materials such as nano-crystalline diamond, Pugno calculates that large defects will unavoidably bring a cable's strength below about 30 GPa. His paper has been posted to arXiv2, and will appear in the July edition of the Journal of Physics: Condensed Matter.
Pugno adds that even if flawless nanotubes could be made for the space elevator, damage from micrometeorites and even erosion by oxygen atoms would render them weak. So can a space elevator be made? "With the technology available today? Never," he says.

Never say never

This comes in sharp contrast to claims made by Bradley Edwards, whose space elevator feasibility study for NASA4 and a subsequent book have made him the most frequent spokesman for the project. Edwards, who is president and founder of the Dallas-based company Carbon Designs, shrugs off the controversy, and says that with adequate funding he could make cables at or above the 62-GPa benchmark in just three years. He suggests that the key step is carefully spinning long nanotubes together in a close-packed way, which encourages cooperative frictional forces that make the strengths of individual nanotubes less crucial.
Pugno counters that the larger defects critically weaken the cable, no matter what its construction. And lab efforts thus far don't seem to inspire much optimism. Ray Baughman, director of the NanoTech Institute in Dallas, published a paper in Science last year3 demonstrating metre-long cables spun in a similar way to Edwards' preferred design. But these too had a strength well below 1 GPa.
Baughman says Pugno's results aren't surprising. It has been known for decades that crystalline materials are sensitive to defects, and that they show a clear drop in strength with increasing size. But he adds that a solution may one day be found. The space elevator, he says, "won't happen in my lifetime, but I don't like to say never."

( http://www.seti.nl/article.php?id=1916 )
 
So why is it that the march of science seems to have halted? In the 1960s and 1970s, scientists talked about decades of development time to get us into space, they expected fusion power by 1980 or 2000, now they talk about centuries. So my question is, why the heck are we paying their salaries if they seem unable to produce measurable progress? Why should we pay so-in-so's salary for the next 100 years with no expectation that he'll produce anything except more doubts and more excuses for not accomplishing anything. The scientists in the first half of the 20th century had a much better track record than those in the second half. In the second half they always make tinier and tinier steps forward until it looks like we aren't moving forward at all. And people wonder why the public turns away from science.

Take each one of the sciences that makes Traveller what it is, and look into the actual research that goes into these fields and the results that come out of it, and what do we see? Backpedaling and excuse after excuse for not accomplishing much. Perhaps if science had a more measurable positive effect in our lives, the public would be more supportive of it.
 
Originally posted by BillDowns:
I've always wondered how the "cable" is strung from a world's surface to a space station?
Other way 'round?

The cable is deployed from the areosynch anchor to the Martian surface in Kim Stanley Robinson's Red Planet.


(Edit: Changed "geo" to "areo.")
 
Originally posted by Laryssa:
[QB] So why is it that the march of science seems to have halted? In the 1960s and 1970s, scientists talked about decades of development time to get us into space, they expected fusion power by 1980 or 2000, now they talk about centuries. So my question is, why the heck are we paying their salaries if they seem unable to produce measurable progress?
You're not "paying them to make progress" - You're paying them to do science. Sometimes people's ideas just don't tally with how reality really works - it's stupid to blame a scientist who points out that there's a flaw in some idea that was never proven to work in the first place.

As for fusion and so on, blame the politicians for that, not the scientists. If the politicians had actually stopped faffing around and arguing about where to put this new fusion test reactor they're building, it would have been up and running years ago.

Why should we pay so-in-so's salary for the next 100 years with no expectation that he'll produce anything except more doubts and more excuses for not accomplishing anything. The scientists in the first half of the 20th century had a much better track record than those in the second half. In the second half they always make tinier and tinier steps forward until it looks like we aren't moving forward at all. And people wonder why the public turns away from science.
In part that's because science is by necessity becoming more and more esoteric - the 'obvious' things were mostly discovered in the 19th and early 20th centuries, now it's more a case of refining what we know. Discovering tOtally new fields is a bit rarer nowadays.


Take each one of the sciences that makes Traveller what it is, and look into the actual research that goes into these fields and the results that come out of it, and what do we see? Backpedaling and excuse after excuse for not accomplishing much. Perhaps if science had a more measurable positive effect in our lives, the public would be more supportive of it.
Then you are clearly unaware of or are ignoring the obvious advances that have been made in recent years that are beneficial to people. There's no "excuse after excuse", there's no backpedalling - fact is, science is about reality, not fiction. Don't blame scientists just because the universe doesn't work the way it does in some fantasy world of wishful thinking.
 
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