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Space Elevator vs Wildlife
Posted by
CmdrTaco
on Wed Sep 27, 2006 07:29 AM
from the check-and-mate dept.
from the check-and-mate dept.
An anonymous reader writes "The longest test yet of the technology that might one day lead to space elevators has revealed some unusual problems. From the article: "There were several unexpected encounters with wildlife. More than a dozen insect egg colonies had been laid on the tether and curious bats flew around the balloons, apparently attracted by the sound made by the tether's vibrations. Late in the test, swallows were also seen swooping down on the balloons, possibly to sip the morning dew on their surfaces." Maybe all the critters just want to go to space too."
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Just goes to show... (Score:4, Insightful)
Don't Lose Sight of Our Goal! (Score:5, Funny)
No, you fools! It's mother nature trying to keep us from leaving this planet! She wants to take us down with her!
"Oooh, so Mother Nature needs a favor?! Well maybe she should have thought of that when she was besetting us with droughts and floods and poison monkeys! Nature started the fight for survival, and now she wants to quit because she's losing. Well I say, hard cheese." - C. M. Burns
Re: (Score:2, Funny)
"SWALLOWS... IN SPACE!!!"
Followed by:
"BATS... IN SPACE!!!"
Summing up the series with:
"INSECT EGGS... IN SPACE!!!"
You have to end the title "IN SPACE!!!"
Re:Don't Lose Sight of Our Goal! (Score:5, Funny)
*yoinks geek badge*
There, everything's fine now.
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Just goes to show... (Score:5, Funny)
Re:Just goes to show... (Score:5, Funny)
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Re: (Score:3, Funny)
Re:Just goes to show... (Score:5, Funny)
Really? Well, let me try:
but repetition makes it funny (+1 funny)
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swallows (Score:5, Funny)
african or european swallows?
Re: (Score:3, Funny)
AIEEE!
Nature (Score:4, Funny)
Re:Nature (Score:5, Insightful)
Parent
Re: (Score:2, Informative)
Nothing but space, though none of it empty (Score:3, Interesting)
I wrote a paper about this once. [west.net]
The entire universe is "vacuum" if by "vacuum" you mean the absence of "solid, extended" matter.
Matter isn't solid. It's make of loosely bound atoms. Even atoms aren't solid. They're tiny nuclei surrounded by lots of "empty" space, filled only with infinitesimal electrons (i.e. point-particles, with a size of precisely zero) and the forces they exert. Those fo
Other issues and possible resolution (Score:5, Interesting)
Like the static we discharge walking around the office, any critters setting up home will be in for a nasty shock.
It's Probably a Valid Concern (Score:5, Informative)
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Re:It's Probably a Valid Concern (Score:5, Insightful)
Probably nothing very different to a good thunderstorm. High voltage discharges through the atmosphere aren't anything unusual. Might not be a good idea to live next to the thing.
You have to realise that the ionosphere is fundamentally unstable, in the same manner that a waterfall is unstable. It's continually eroding and discharging, and only appears to remain there because it has a continual feed of new energy (from solar radiation). Thunderstorms are the most common way for it to dump excess energy. We could perhaps create a small region in which there is an unusual electric field, but we can't do any real damage any more than you can damage a river by standing in it. It may be assumed that all people and equipment near the top of such an object would have to be shielded in the same manner that all space equipment already has to be (since it operates beyond the ionosphere), so it shouldn't cause any significant problems in that respect. The most likely effect of the thing is to reduce the number of thunderstorms in the immediate area (because there will be less voltage around to cause them).
It should be an interesting experiment to put up a really tall lightning conductor and see what happens.
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Re: (Score:3, Informative)
They've conducted several experiments on electrodynamic tethers [wikipedia.org], but they work on different principles than a space elevator would. An orbiting tether generates its charge by its motion through the earth's magnetic field the same way a spinning magnet generates electricity in a coil of wire in a
Re:It's Probably a Valid Concern (Score:5, Informative)
My big gripe about these experiments? They're working on ironing the kinks out of a climber on a tether, and ignoring the 800lb gorilla in the room: namely, that a space elevator from Earth needs to be built out of unobtainium to be realistic.
Most serious proposals (ones that actually consider the economics) require a tether strength the density of graphite with a tensile strength > 100GPa. Many want higher -- > 120GPa. The reason is the taper factor. You get much lower and the taper factor becomes huge. A huge taper factor means a vastly increased launch weight, pushing the costs into fantasyland. They'll often cite studies showing that SWNTs (Single-Walled Nanotubes) have 100, 120, sometimes even more GPa predicted tensile strength. There's a big problem with that: they don't have that sort of strength. Measured strengths of SWNTs have capped out at just over 60GPa. Now, this could be from imperfections in the tubes, but it's quite possible, due to the way that the tubes form (extruded from a tiny ball of molten carbon -- this sometime even leads to them looking like "strings of pearls" in places) that imperfections are, for the forseable future, an inherent part of SWNTs. It's also possible that even perfect SWNTs just aren't that strong. Either way, this is a huge roadblock -- one that's not going to be solved, commercially, any time soon. Possibly never.
Then there's the next potentially fatal flaw to the problem: nanotube ropes. CNTs naturally align into ropes (they can be hard to get separated in fact). Unfortunately, they naturally align into haphazard ropes, weakening them. Even a flawless rope, however, faces some serious fundamental problems. The ropes are held together by VdW and pi bonding -- not nearly as strong as the orderly CNT sp2 bonds. With the ability to make flawless, extremely long CNTs, and align them perfectly into ropes, the long individual tube length could supply enough force in the VdW and pi bonding to hold the ropes together under the sort of pressures that cause the tubes to break. In the real world, however, we're typically limited to about 20GPa.
However, CNT ropes are only part of the problem in themselves. You need to make a fiber or fabric out of them. Once again, imperfect bonding and manufacturing problems step in the way, reducing your strength by a significant factor yet again.
See the problem? They quote the *theoretical* strength of *unlimited length* *individual tubes*, and pretend that we're right around the corner from being able to produce a tether like that. We're not even close. This is *The* challenge with a space elevator. The amount of engineering to achieve such strengths, if they're even possible (a very big if), vastly exceeds the engineering needed to make a photovoltaic-powered machine climb a rope. They want to be seen as making progress, but really, they're spinning their wheels unless a (quite possibly impossible) material to make the tether out of, affordably, is discovered.
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Re:Other issues and possible resolution (Score:5, Informative)
Now the situation is a little different if the object is charged. Then, when you touch it, charge will tend to flow from it to you (as you are uncharged). If you're touching an area of lower potential, you'll get a shock, just as the GP mentions. If not, then you'll simply become charged. What happens then depends on a number of factors; perhaps you'll bleed the charge off naturally, perhaps you'll retain some of it until you ground yourself and get a delayed shock (just as you do when touching metal after charging yourself on carpet, etc).
I suppose if the thing is charged enough, then the short-lived flow of charge into the body could deliver enough of a shock to be problematic, but I'm an (ex-)physicist, not a physician, so I don't know for sure.
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Buckle and deformation problems (Score:5, Interesting)
Hm... do you think that if your tether is beginning to BUCKLE AND DEFORM, you might have a slightly more fundamental problem than just needing to redesign the robot?
Well, I'm sure they're aware of it. But this kind of thing probably won't become more obvious until they do a 6-month test, I guess. Or 6-years. But the potential for your tether to break off eventually is probably going to be a slight drawback.
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Bats, man. (Score:5, Funny)
robot tests are dumb (Score:3, Insightful)
Re: (Score:3, Informative)
Thanks.
Re:robot tests are dumb (Score:5, Informative)
That being said, how far off were we when this idea was first concieved, or practical work began? A factor of 1000? 10,000 ?
Anyway, we do stuff like this because it's fun and achievable. Most people who follow this sort of thing know that material strength of tether is the current limiting factor, and there is ongoing research in this field.
But there are plenty of people who don't have the expertise to contribute to the material strength problem, but they can sure have fun screwing around with climbers, can't they? The work has to be done sometime anyway.
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Putting it in perspective (Score:3, Insightful)
Trying to put everything into perspective, the elevator is probably the least offensive solution in terms of the environment.
Re: (Score:3, Funny)
Hey, thanks for putting that in perspective.
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Wait, wait -- is that U.S. or British zillions?
Danger Signs (Score:3, Funny)
Ants (Score:5, Interesting)
Assuming ants can climb up the elevator, I wonder which altitude they could reach, given the fact that they supposedly don't need a lot of oxygen with their small bodies. (I know that ants don't have lungs and breathe through tiny pores, but still)
Re:Ants (Score:4, Funny)
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Re:Ants (Score:4, Funny)
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Wonkavator (Score:3, Funny)
I for one... (Score:3, Funny)
Luckily we will be able to shoot them off the elevator with the laser beam that powers to climber
The structure itself is way less problem.... (Score:5, Insightful)
I'm not saying that is a bad thing, btw. If done will, maybe this technology would be cleaner overall than rockets or some kind of mythical antigravity fusion powered jet-pack thing.
Very promising concept (Score:4, Informative)
"It now costs about US $20 000 per kilogram to put objects into orbit. Contrast that rate with the results of a study I recently performed for NASA, which concluded that a single space elevator could reduce the cost of orbiting payloads to a remarkably low $200 a kilogram and that multiple elevators could ultimately push costs down below $10 a kilogram. With space elevators we could eventually make putting people and cargo into space as cheap, kilogram for kilogram, as airlifting them across the Pacific."
The article answers many space elevator-related questions. Those who want to know more about the project can read it here:
http://spectrum.ieee.org/aug05/1690 [ieee.org]
There are some technical problems (mainly related to construction of the cable) to be solved first, but the space elevator idea is definitely worth serious consideration, as it could provide humanity with extremely cheap and easy access to space.
Re: (Score:3, Informative)
Maybe... (Score:4, Funny)
If we manage to attract enough squirrel... (Score:3, Funny)
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Re: (Score:3, Insightful)
Re:Time..... (Score:5, Informative)
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Re:60,000 mile tether - not possible (Score:5, Insightful)
A space elevator sounds great, it just seems far-fetched. A 100 meter test. Only 96,560,540 more meters to go.
Ah, I see that your glass is half empty. While you say "A 100 meter test. Only 96,560,540 more meters to go" implying it's impossible, we say "A 100 meter test! Only 96,560,540 more meters to go" with the idea that we're simply going to do that 100 meter test 965,600 more times. Yes, that oversimplifies things, but it's a half glass full kind of perspective.
Consider: As I understand it, the wiring in the Golden Gate Bridge, if layed end-to-end, would stretch around the globe three times over. Considering the circumfrence of the earth is something like 40,000km, that would mean that we've already built bridge structures that incorporate over 100,000km of cabling. Granted, the design of the space elevator is completely novel; but this stuff is based on modern engineering understanding.
People get the scale of this whole project wrong. The initial ribbon would need to be small and slender and thin for weight purpouses of the initial ribbon. After that's established, we would start adding mass to the space elevator, until it's a megastructure, not unlike the Golden Gate Bridge. Eventually, the dream is to create a verticle subway system of sorts. Access to space would be cheaper than rockets once the space elevator was built up to the scale of the Golden Gate Bridge or the New York City Subway System.
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Re:60,000 mile tether - not possible (Score:4, Funny)
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Re:60,000 mile tether - not possible (Score:5, Insightful)
-- Overheard circa 1903
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Re: (Score:3, Insightful)
For one thing, it would be sensible to have some military presence guarding the elevator to prevent any airborne attacks. But even if it did happen, it would only affect the bottommost part of the ribbon (it will be over 60,000 miles long, remember). All they'd have to do is lower a little bit of the ribbon and re-anchor it.
Your model airplane scenario is pretty silly, BTW. A couple of CIWS (Phalanx) cannons co
Re:What about Airplanes? (Score:4, Interesting)
I would bet this has already been thought of, but I'd be curious to see what came of these thoughts?
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Re: (Score:3, Funny)
Obviously the solution is to make the tube twice as long and bend it in half so t