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NPR Talks Skyhooks
David writes "NPR's Talk of the Nation this past week featured Brad Edwards, President of Carbon Designs Inc., to talk about their plans to develop an elevator that would lift people to an object orbiting in outer space. The project's homepage details their plans and ambitions. The discussion expands on callers' concerns about such problems as commercial airliners running into the super long cable or if it would act as a conduit for lightning."
Does the audio program mention the word "skyhook"?
Why bring up the Aussie 70's supergroup?
I hope this isn't going to be anything like the escalator to nowhere...
What does this button do...
Wow, our society has changed. The concept of airliners being uninformed of the location of these cables or whatever they are is just plain stupid. Of course they will know that they're there. Not to mention, even if they didn't know, the chance of a collision is fabulously small.
People should be more worried about if this is the best way to spend money or not. Personally, I think it's a pretty sweet idea and I'd be totally for supporting it. Looks quite awesome, actually!
Would Not Like to be stuck if that elevator breaks down :|
Here is some money that NASA could "invest" in another x-prize like compitition. Get some innovation back into the space game. Maybe once China starts blasting some people towards Mars the US will get off its ass again.
The more you know, the less you understand.
From TFA:
We firmly believe that the set of technologies that underlie the infinite promise of the Space Elevator can be demonstrated, or proven infeasible, within a 5 year time-frame. And hence our name. Elevator:2010. we promise to get an answer for you by then.
Message 5 years from now:
42
"A door is what a dog is perpetually on the wrong side of" - Ogden Nash
I was thinking the same thing. It's way overhyped. Although, the concerns cited in the summary aren't that major.
Commercial airliners will never get close to it; that's what no fly zones are for. Even if an airplane crashed into it, one solution successfully deals with both airline impacts and lightning: "maypoling" the skyhook as it nears the ground (i.e., splitting it into several cables, of which most, but not all, are needed for stability/strength.) As for lightning itself, most types of CNTs would be the "path of most resistance", barring heavy condensation on the cable. Plus, some sites in the world have very little lightning.
We should start dealing in those black-market beagles.
The longest song in my MP3 collection is 22:43 (Autobahn by Kraftwerk - even on topic, sort of...) Is that long enough for the ride up? How many quarters do I need to put in the slot?
This issue is a bit more complicated than you think.
Don't space elevators have to be built along the equator?
According to the website, the elevator will move at 200 mph. Considering that our atmosphere is roughly 380 miles, I'm going to have to listen to Kenny G for almost 2 hours!
*Don't space elevators have to be built along the equator?
I thought this as well, but no, they don't. A rough diagram of a space elevator would be:
O--------
Where the "O" is the Earth. Imagine, right before "tying down" the base of your elevator, you drag i "up" a few dozen degrees to New York. The farther North you go, the more of an angle it will have, but it's not unstable so long as it's anchored.
The first thousand miles of the climb would be like a very steep gondola ride.
Pulp Audio Weekly - Geek News and Reviews
It isn't overhyped until there are competing groups actually building one. Furthermore, what is "overhyped on slashdot" is rarely even in the public consciousness. Live with it, love it, until it spills into the public imagination and gets warped into an evil, multi-national corporation's wet dream. THEN complain.
I agree that most of the technical objections are not-too-hard-to-overcome engineering challenges, not showstoppers. If you're reading this and think you have a fatal flaw to the whole concept, and haven't spent months on it doing some calculations and reading papers, I'll take the opportunity to laugh at your idea now.
Professor of Astronomy, Author of Spider Star & Star Dragon (Tor)
I guess the old prank of jumping onto a crowded car and pushing all the buttons would be a no-no...
Seeing bad movies only encourages them. Watch responsibly
Motherfucking Kraftwerk! That kicks ass.
It always comes up, but protecting a space elevator is really
simple to solve. Put the base in the ocean, and stick a carrier task force there to protect it.
We already have an example to follow. Fort Knox has a tank combat training ground there, and plenty of tanks stationed there permanently. Good luck trying to raid the place.
Terrorist attacks are dangerous because they could happen anywhere, but that doesn't mean that we can't make a single known place extremely secure from that sort of thing. If it is decided that no aircraft will approach within 100 miles of a space elevator, a single carrier task group could enforce that easily. Revenues from the space elevator would easily pay for the security force too, and it'll still be the cheapest way to get something into space.
Fascism trolls keeping me up every night. When I starts a preachin', he HITS ME WITH HIS REICH!
I find this technology very intriguing. But it took me a long time to realise that they are serious. First time I heard about this I had to check if it was April first.
Anyway, the most interesting thing I heard in this interview was that they said that if you let the elevator go up really far, close to the counter weight, and let go of an object there, it would fly faster than with conventional rockets because of the centrifugal motion.
So that could be used to fling stuff from earth really fast. And since the earth angle varies quite significantly it can be sent to a a great different places.
There is still a large number of directions that one of these objects can't go too, but, still, pretty cool.
The Internet is full. Go Away!!!
% mplayer -ao pcm:file=20050603_totn_03.wav 'rtsp://real.npr.na-central.speedera.net:80/real.n pr.na-central/totn/20050603_totn_03.rm'
Should work if one has mplayer but does not have realplayer.
ZP
We only can learn from our mistakes.
... it's so much more eloquent...
kulakovich
Doesn't an orbit have to go around the center of gravity of what its orbiting? If so, it wouldn't be able to simply always be 'over' NYC. Right?
Yes, an off-equator tower would connect an anchor to an equitorial geosync satellite at an angle. Pitch from an equatorial anchor is 90'; polar pitch is 0'. At about N40' latitude, the cable would appear to head South, rising at 50'. Such a "leaning tower of New York" would stretch across the southern half of the Northern Hemisphere, along the East Coast, the mouth of the Caribbean, and NE South America. The lower part of the tether could include radio equipment working like traditional geosynchronous satellites, but with much less latency, owing to the much lower elevation. Taking the place of the old WTC antennae, which, though higher than practically any other building in the US, still had a relatively close horizon. The question is whether the tether's tensile strength can handle the force vector at 40' to its linear axis, rather than the typical 0' when it's normal to the equator. And whether any sag would make the already longer distance inefficient, either in ascending travel or manufacture (shipping the tether anchored to a ship to be reanchored in NYC) remains to be seen. But the WTC v1.0 was expensive - it would have been cheaper to build it in Puerto Rico or Ecuador. But not nearly as useful to New Yorkers. Let's make one!
--
make install -not war
Bad puppy, no treat!
I laugh at uninformed opinions. I've also made five figures on the hardback/paperback book, so I guess I'm laughing all the way to the bank.
Sorry for feeding the troll -- someone should mod the parent as offtopic.
Professor of Astronomy, Author of Spider Star & Star Dragon (Tor)
Tower of Babel, thank you.
The satellite is "over" the equator, but where you anchor the cable on the surface of the Earth doesn't have to be on a straight line between the satellite and the center of the Earth.
Pulp Audio Weekly - Geek News and Reviews
The last time I saw skyhooks actually being used was on PBN! http://www.paintball-net.com/
o ticfairytale=}{=FireDrake=}{=The Lost Souls=}
a padded multiterrain insulated suit[skyhooks][refracto]{=DavidRM=}{=Dug=}{=Psych
I want to be retired when I grow up.
42 is the answer to the life, the universe, and everything in The Hitchhiker's Guide to the Galaxy.
Professor of Astronomy, Author of Spider Star & Star Dragon (Tor)
Covered a lot of the questions that have popped into my head while reading the previous 947 Slashdot/Space-elevator articles.
Highlights
- Location? Straight south of California near the equator.
- Timeframe? 15+ years
- What if an airliner flew into it? Pretty much screwed. But the location is 400 miles from any air route so shouldn't be a problem.
- How long would it take to get up? A few hours.
- Wouldn't it be a huge lightning rod? Yeah, but that area of the world does not have lightning, so shouldn't be a problem.
- Wouldn't the car that goes up the cable just pull it down and not crawl up it? Yes, but the car is only a few tons and the weight of the cable and weight on the other end was something like a couple thousand tons. So shouldn't be a problem.
There are a lot of "shouldn't be a problem"'s in there that one of them will be a problem. Exciting technology though.
Have you ever run up a flight or two of stairs? Just getting going isn't good enough. You need a sustained input of energy to keep going.
This elevator will propel its payload straight up at 200 mile/h, using solar power? Those are mighty powerful solar panels.
In a nutshell, you have to supply escape-velocity energy to any mass you drag up the thing. No two ways about it.
What it's like to get stuck mid-air on a long lift.
God help you if the elevator goes on the fritz in the midst of your ride!
sigs are for losers (except to point out that sigs are for losers)
What kind of damage can the ribbon sustain if a small meteorite or space junk impact it? No big deal or total failure?
Authority questions you. Return the favor.
http://www.isr.us/video/SE-INTRO_Final-1stream-384 .wmv
Covers the basics of the elevator, what it looks like, how it works, etc...
The question of how this thing is powered never popped into my head before, but the video shows that they will use a lazer shot from the base station. Crazy stuff.
I could probably use that to find myself a life...
I don't think the space elevator is quite as ambitious as the tower of Babble, After all the space elevator only goes to orbit, not to Heaven.
As long as you're maypoling near the bottom (which introduces a railroad switch like complexity to runners traveling up/down the elevator), you may as well maypole near the middle where satellites are most likely to hit the elevator, so that the platform on the ground (sea or mountaintop) doesn't have to be moving around. You simply rotate, say, two cables 10 kilometers apart, 90 degrees as needed to avoid collisions, death rays and the like.
At that point, maypoling should be used at the top too, in reverse, so that there only needs to be a standard width for the cables, making them cheaper to manufacture over a highly tapered single cable. If the same machinery used to build suspension bridges and other things can be used for the space elevator, the sales volume will make it even cheaper.
Having to negotiate intersections introduces an extra complexity, slows down the speed of travel and adds extra weight, but it may become a desirable complexity at some point if it allows simultaneous up/down travel (i.e. more capacity), can be extended to make travel easy between elevators, etc.
Yeah but they've got a slight problem - we don't yet have the technology to make a cable strong enough. Until we do it's just so much science fiction.
If you're reading this and think you have a fatal flaw to the whole concept, and haven't spent months on it doing some calculations and reading papers, I'll take the opportunity to laugh at your idea now
Actually the concept, physics and calculations are quite simple (took me about half an hour to work out the tensile strenght required in the cable), the only question is how strong nanotubes can be - and nobody can answer that.
Stairway to Heaven vs Skyhooks -- hell, i know which one i'd choose and i wouldn't even think twice about it.
Man is a slave because freedom is difficult, whereas slavery is easy.
Yes. I'm not laughing. That's an informed opinion based on knowing something about material science.
Progress has been fast with CNT materials. The promise (which is a promise not a certainty) is that we'll know if we can make a strong enough material in the next five years based on CNT technology. Investing in this sort of research is a good idea (and we nearly hired someone this year who worked in the area).
Professor of Astronomy, Author of Spider Star & Star Dragon (Tor)
It wont be a problem. The carbon ribbon doesnt weigh much - and when 10,000 miles of silver foil lands on a town, someone will just open a beowulf cluster of christmas wrappping stores.
------
beware he who would deny you access to information, for in his mind he dreams himself your master
Of course your first point is a restatement, as an answer, of the "question" (issue, really) that I posted, which you quoted.
The other point is the details of that issue. How much heavier would a 40'N cable have to be than a 0' cable? Therefore, how much force is exerted on the anchor? And how much volume of harborbottom much is needed to exceed that force, including the cargo loads, and possibly even variables like lunar tides and other perturbers? If the cable is anchored to a giant sack of muck in the harbor, or farther out to sea, that would both distribute the force across the sack's surface, and contain the weight to anchor.
FWIW, I suggested the harbor, not the top of a building. Our suspension bridges here in NYC are anchored in big blocks sunk into the riverside mud. The skyhook website claims an (assumedly equatorial) tether would weigh only 1000 tons. If a 40'N tether isn't orders of magnitude "heavier" in force pulling the anchor point, such an anchor seems possible.
As for the prematurity, one thing you learn early in NYC is to start asking for what you want ASAP. Why wait for the previous guy to get out of the way, when they're already listening to the next orders? At either the deli or the skyhook counter.
--
make install -not war
One weakness of the plan, as I see it, is the all or nothing nature of the plan. A less risky plan that could be a stepping stone to a space elevator is to start with a much smaller rotating tether in orbit.
Imagine a thousand mile long tether in orbit with its center of gravity 600 above the earths surface. In addition to orbiting the earth The tether would rotate about its center of gravity at a rotation speed such that its speed relative to the earths surface at its ends closent approch would be zero.
A rocket would have to ascend to 100 miles up and rondezvous with a a tether end that, for the moment, is stationary. It would remain atteached to the tether while the tether rotated 180 degrees about its center of gravity. At tht point the rocket would be 1100 miles above the earth and traveling at about twice orbital velocity. If the rocket detatched at this point would would be well above escape velocity.
Longer tethers would reduce G forces and avoid the need for the first 100 mile step. The ultime version of the tether would have a CG in geosynchronous orbit and aon end on the ground.
http://www.unmuseum.org/spaceelevator.htm
Slow down cowboy!
There will be a google story along shortly that you could repost this comment to.
liqbase
I thought Dr. Edwards went through some interesting verbal gymnastics at one point to avoid mentioning anyone else by name ..
...funding to do it, from private sources, from commercial sources. But since it's new, it always takes a bit of time to be accepted.
FLATOW: Is there a business here? Is this a private project, much like the space plane was?
Dr. EDWARDS: Well, right now the space elevator--up until a couple of years ago, very, very few people knew about it. And so it's really
just getting started. There's a couple hundred researchers now that have sort of taken up the torch and are working on it at a number of
locations, including Los Alamos National Laboratory, some private companies, some people at MIT, various locations. And right now,
there's not a dramatic amount of funding for it, and that's part of what we're working on is to get...
FLATOW: Yeah.
Dr. EDWARDS:
FLATOW: Right. How...
Dr. EDWARDS: Usually people look at first thing they think is it's crazy.
FLATOW: That didn't stop a lot of people from making what they said they would.
Dr. EDWARDS: Yeah.
Okay, sure, Edwards is running a startup and looking for funding but it can't hurt to tip the hat a bit to your competitors. If 'competitors' is even the proper word for an industry that by and large doesn't exist. Granted, I'm biased in that regard.
Display some adaptability.
If you're reading this and think you have a fatal flaw to the whole concept, and haven't spent months on it doing some calculations and reading papers, I'll take the opportunity to laugh at your idea now.
This seems to be an appropriate response to virtually every discussion on every Slashdot story ever. I'd like to nominate that this reply be hardcoded into the slashcode to be automatically inserted at a random point in every story's comments.
Kudos, sir.
One of the issues that I keep reading about a space elevator is how the cart will be provided energy to move up. Well, how about a space goldola instead of a space elevator. Why not have the orbiting mass have a pulley connected to two pulleys on the ground with each at a seperate ground (or ocean) station seperated by several kilometers. The accute triangle that this system would create would allow a space gondola to ride up a moving cable without getting entangled. The cable, of course, being moved by the ground station allowing the gondola to carry more weight. The gondolas could also be returned to earth rather than discarded into space when the orbiting mass becomes massiv enough. Another benefit is the ability to easily repair a camaged cable. As the cable passes through each ground station a L.A.S.E.R. could scan the cable for small fractures and they could be repaired. The cable could be thickened in the same fashion by adding more layers to the existing cable as it passes through the ground stations. And another benefit of this three pulley system is in the event of a catastrophic failure of the cable. If the cable breaks at a single point, the breaks can be applied at the orbiting mass and at the ground stations. No matter where a single break is the mass will be connedted to at least one ground station. Space gondolas, w00t!
Welcome to the land of the free...pay toll ahead...no photography...please open your bag...
I thought space elevators with cables were out (due to the tensil strength the cable should have) and space fountain were in (since easier to build, not just buildable on the equator, etc.)
http://en.wikipedia.org/wiki/Space_fountain
If you're reading this and think you have a fatal flaw to the whole concept, and haven't spent months on it doing some calculations and reading papers, I'll take the opportunity to laugh at your idea now.
Not required. One can easily present another's informed opinion, if the other person has spent months on it doing calculations and reading papers. And there are lots of those out there.
We should start dealing in those black-market beagles.
Why build a skyhook? You know Dash Rendar's just going to fly by and blow it up...
#define QUESTION ((bb) || !(bb))
Actually, 1/3 of carbon nanotubes are metallic, which means they are extremely conductive. Even the tubes with a bandgap would most likely have a smaller resistance than plain air. It would make a good path for lightning.
However, my initial thought is that lightning would not be a problem because the grounding that the tubes would provide would prevent charge buildup that leads to lighting in the clouds to begin with.
> Put the base in the ocean, and stick a carrier task force there to protect it.
/ nr.html
Better yet, put it on Nauru.
http://www.cia.gov/cia/publications/factbook/geos
With the phosphates gone, the international money laundering (er banking) industry dismantled, and nothing else on the horizon, this could be just what this island nation needs.
Finally something that severe isolation is good for.
XJS*C4JDBQADN1.NSBN3*2IDNEN*GTUBE-STANDARD-ANTI-U
in which case all you have to overcome is friction. (a la Traction Elevators, Paternosters, Funicular Railways, etc.)
I always love it in SciFi novels when their space elevators snap because of a terrorist attack or one failed component in an insanely long chain of parts.
Fantastic.
Seeing it hasn't been brought up yet, no material strong enough to build the elevator yet exists. It is not yet clear whether it is even possible to do so. Carbon nanotubes may be strong enough, but nobody has yet been able to assemble them together into a "ribbon" of the strength required yet.
Any sufficiently advanced technology is indistinguishable from a rigged demo
--Andy Finkel (J. Klass?)
At the time, it was better known as Babel. It wasn't named Babble until the people could no longer understand each other.
Later of course, Babel and Mabel got together and had lots of Baby Bels. The runt of the family was nicknamed Deci Bel.
Time flies like an arrow. Fruit flies like a banana.
I think your objection falls under the heading of "reading papers." If someone does trot out another's informed opinion, I hope they actually understand it! I've actually read Edwards and Westling's book on the Space Elevator, for instance. There are too many SE threads on slashdot, I agree, but despite that fact, every one seems to draw new people who make the same basic objections that are easily answered. On the one hand these are easily answered, making the forum educational. On the other hand, for this particular forum it is tiresome (hence your original "Cripes!" I think).
Here with the SE concept, these uniformed objections don't matter too much. With other issues, like evolution or global warming, there are too many arguing by parroting other's positions just to support their own sense of religion or politics, without understanding or caring about the science. So I guess I have a chip on my shoulder.
Professor of Astronomy, Author of Spider Star & Star Dragon (Tor)
How could a /.er not know that joke?
I am a viral sig. Please copy me and help me spread. Thank you.
1/3 != most. That's why I specified "most", not all. And while I don't have the numbers on hand in comparison to air, CNTs are often excellent insulators - there are plans to use them as such in some designs for next-generation microprocessors.
We should start dealing in those black-market beagles.
Now that it's been a major motion picture - how could a member of western society not know that joke?
Killfile(TGK)
No trees were killed in the creation of this post. However, many electrons were inconvenienced.
The ribbon is 62,000 miles long
The climbers travel at a steady 200 miles per hour
That's one hell of an elevator trip. The new opportunities this provides for artists of Elevator Music alone should make this venture worthwhile for someone.
If you want a picture of the future, imagine a boot stamping on a human face forever.
- George Orwell
...some wiseass physics research team will unveil inertia/gravity control systems capable of turning old oil tankers and freighters into space capable cargo vessels and start hefting whole space stations at once with the greatest of ease.
If my grammar and spelling are off, I am [distracted/tired/careless] (take your pick)
true
I am a viral sig. Please copy me and help me spread. Thank you.
Wouldn't that have the velocity to cause some serious damage?
I tend to agree. I've been trying to get my head around the physics of this thing and I don't seem to be able to. When I hold a string up in the back yard, it just falls to the ground. Maybe if I could put it up far enough, centrifugal force would make it stand up. But I figure it would have to go out to a point where the top (where I'd attach a big weight) would be stable in a geosynchronous orbit. That's about 25,000 miles I think. So maybe I'd need to go out a little farther to take care of the weight of the string.
Oh!! Now I get it. That's where those ultralight, ultrastrong carbon nanotubes come in.
I just went and read TFA. I was surprised that I had, indeed, guessed it right. It'll never work.
I accept your definition, albeit without clarifying the dimensions of each.
As I understand it, a hoytether is a millimeter-scale (micro) structure whereas maypoles are meter or potentially kilometer-sized (macro) structures. What I was intending to propose near the middle section was a two-cable maypole of hoytether-based cables, NOT maypoles instead of hoytethers. Now, if a reverse, hierarchical maypole can be used near the top to provide a tapering effect, that doesn't preclude one from using hoytethers for each of the cables. The weight distribution or energy release characteristics may well be better for such a scheme.
One thing that I also left out is that, for the middle section, I was thinking, not in terms of a single maypole with two cables hanging down, but one where the cables meet back up again to form a reverse maypole at the bottom, similar to how train tracks accomplish the same feat. (Let the analogies of this to the transcontinental railroad begin...)
Further, I am not proposing maypoles as a solution to aircraft impacts (although indeed a million little cables hanging down would be difficult to knock out, wouldn't they?). Primarily, I see them as a way of making it possible to affix an SE to a mountaintop while still allowing the structure to dodge orbiting objects with predictable orbits.
The elevator is all find and dandy, but the real money is gonna be made by those that develop the unobtanium mine. That elevator is almost entirely out of this stuff.
Like building a tower of babel is hard! I've built serveral, the secret is realising that
"ooo heavean is a place on earth"
I thankyou.
In the not too distant future, next Sunday A.D.
Suitcase nukes exist, sort of. While it's not quite something you'd carry in a suitcase, the Special Atomic Demolition Munition was a 1-kiloton nuke that weighed about 68 kilograms. You're not going to carry it in your suitcase unless you're He-Man, but you could certainly fit into the trunk of your car, even a French one ;) However, the odds of a terrorist group being able to build a nuke this small are fairly minimal without being handed the design by somebody else.
The resources and experience required to build a nuclear weapon are also somewhat less than is commonly believed; this article on the former South African nuclear program gives some idea of the minimum budget required for the job from scratch- tens of millions of dollars, but not hundreds. I should add that I'm highly skeptical that any terrorist group could coordinate this kind of money and people, in secret, for long enough to pull such an accomplishment off.
Finally, uranium, even enriched uranium, or plutonium is pretty hard stuff to detect; they just don't emit very much radiation until you push them into a critical mass! Bruce Schneier's blog links to an extensive report on the topic; he also links to news reports about how the detectors they have bought detect so many false alarms as to be essentially useless. Maybe the three-letter agencies have something better (for instance, looking for chemical traces of radioactive material rather than radiation itself), but if it is it's kept pretty secret.
Still, you're basically right. Terrorists aren't going to be whipping up nukes to send through the mail any time soon.
Any sufficiently advanced technology is indistinguishable from a rigged demo
--Andy Finkel (J. Klass?)
If this project means that Americans finally manage to learn foreign languages, I'm all for it!
Real Daleks don't climb stairs - they level the building.
So, you've got this single cable with one, two? elevators which take several hours each to get things into space and then another several hours to get back down and it's supposed to be cheaper than firing them up with rockets?
How does that work? Economically I mean.
As opposed to lots of companies competing to build cheaper rocket or similar technology, launching in parallel.
Deleted
I think what most people miss is that there are limited possible locations for the elevator, because you have to make it orthogonal to earth's rotation axis and, ideally, you want it on the equator - even better would be anchored to a mountain on the equator.
What's really interesting about the tensile stress is that it's possible to make the cable long enough so that zero anchor force is required at the surface of the earth :) You can also reduce the maximum tensile stress requirement if you allow compressive stresses at earth surface.
"There are a dozen opinions on a matter until you know the truth. Then there is only one." - CS Lewis (paraprhase)
I didn't say that, only that the energy required is a lot less than a dead-lift to orbit, if there's a counterweight (which could be by proxy, since space elevator discussions often involve recovering and storing energy from inbound (descending) loads for the benefit of outbound loads.)
The space fountain (and by extension, the Lofstrom Loop) are so utterly silly to the normal person that they would *never* be built. For one thing, you're essentially talking about shooting a continous stream of bullets into space where you catch them and shoot them back at the ground, in a large circle.
Yes, it could be done; no, there's not a chance in hell that it ever will be.
- Give a man a fire and he's warm for a day, but set him on fire and he's warm for the rest of his life.
Down is pretty easy...
Extra cables are indeed a nice thing in space, but there's a mass tradeoff. If you don't regularly affix them to one another, they're not strength-redundant. If you do regularly affix them to one another, the more frequently they're affixed, the better they take an impact, but the mass requirements grow quickly, and with a space elevator, mass requirements are already ridiculously constrained (currently, far beyond anything that we're capable of). That's why I proposed only doing the very tip of the tether - the earth atmospheric intersection point - as a maypole. The length in the atmosphere is almost insignificant compared to the total length.
The main cable should only be able to withstand micrometeorite impacts, in my view, so as not to increase its mass significantly. I agree about the importance of moving the tether for dodging debris, of course - I think that will be critical for any application like this.
We should start dealing in those black-market beagles.
- What happens if the cable breaks?
- A space elevator will conduct all of the electricity out of the upper atmosphere, destroying the ozone layer, because, as we all know, carbon is highly conductive, and so is the atmosphere.
- As mass is moved up into space, it will slow down the Earth's rotation, which will make all of our clocks inaccurate, because a space elevator will be able to move an amount of material large enough, compared to the mass of the entire Earth, that it will have a detectable effect.
- People going up the elevator will spend too much time in the Van Allen Belt, which will expose them to excessive radiation, which will sterilize them / give them cancer / etc., because modern technology is incapable of shielding them from such radiation.
- Carbon nanotubes were first produced over five years ago, but let's be generous and say that they were first produced five years ago.
- A space elevator would make a tempting terrorist target, because it would be so easy to get to or sabotage.
How's that?It will wrap around the Earth / split the Earth in two / kill millions of people / etc., rather than burning up on reentry or fluttering softly to the surface.
And it will cause tremendous damage in the immediate area, because the Earth terminus will not be out in the middle of the Pacific Ocean, away from all major shipping lanes and flight paths.
Also, since the Earth will weigh less, it won't be able to hold onto the Moon, and the latter will spiral out of orbit.
The longest carbon nanotube produced so far is less than 1 millimeter long, but let's be generous and say that the longest carbon nanotube produced so far is one millimeter long.
Since, as we all know, progress on such things is linear, at 1 mm / five years, it will take, uh, uh, a helluva long time before we can make nanotube strands 22,000 miles long.
And they have to be 22,000 miles long, because the elevator cable can't be made up of shorter sections fused together / glued together / held together by Van Der Walls force.
The ability of a terrorist to get through real security (as opposed to the joke security we have at our airports) has been demonstrated time and time again by the vast numbers of successful terrorist attacks launched against the Space Shuttle and other rockets.
Those who sacrifice security to condemn liberty deserve to repeat history or something. - Benjamin Santayana
Yeah, that looks like a good starting point for a FAQ. You forgot a few, like meteorites, and drawing the unwanted attention of extraterrestrials. Also, the impossibility of initially launching such an enormously long and heavy cable.
Professor of Astronomy, Author of Spider Star & Star Dragon (Tor)
"an ideal platform for your corporate message."
Please! Please no advertisements on this thing! Advertisements are showing up *everywhere* and I'm SO sick of them!
And now they plan to create such a beautiful tool... and you can buy advertising space on it?
(ObFunny: at least there's plenty of space on it, haha)
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Moderation -2
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What kind of insane TrollMods are you? Auditioning to fly planes for the Qaeda?
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make install -not war
The 100 mile lower limit in my example was selected as an estimate of a point where drag was neglible. If not, change it to a point where it is effectively zero. Remember that the path of the endpoint is essentially straight down to 100 miles and then straight up.
The forces in my 1000 mile example are much less than they would be in the 55,000 mile full space elevator. The point is that the length would be driven by the available materials.
...And if anyone is still worried about lightning, it would be possible to attach the bottom of the cable to a airship which floats above the weather and can control its own ballast and therefore altitude. This would require periodic relief flights from 2 or 3 other airships based nearby, but the technology is off the shelf at this point. If all of the airships are damaged, at the worst case the anchor weights it is holding up sink to some stable equilibrium at ground level.
Not having a base station on the ground also solves problems such as tsunami, atmospheric aircraft (they can't fly that high), and it makes the cable that much harder to find in the first place. The only major catch (that I can think of) is that it requires the base to be near the equator.
"The length in the atmosphere is almost insignificant compared to the total length."
True, but the bottom is also where gravity is pulling at its strongest. Any savings of weight in that section goes a long way to reducing the size of the rest of the cable. Conversely, adding extra mass near the top adds almost no weight because the mass is in microgravity.
In theory, yes, maypoles are going to be less strength redundant, but they can be more spatially redundant. That is, a meteor shower is less likely to take out the whole thing if it is spread out over several kilometers and if the meteors are closely bunched together. Also, consider that repairing or replacing one of several cables is less tricky than repairing the only cable that is holding everything up.
Perhaps maypoles and mountaintop stations will be too fancy for the first elevator, but in preparation for major meteor showers I think they will want to consider those options.
Actually, for the competition, We are only aiming for 1 m/s for 50m up a tether. Power will be supplied by a 1300W (or so) searchlight. Most groups will likely be using sattellite solar panels. In future competitions these are expected to be increased, and presumeably power will eventually be supplied using a laser. The winner will be determined by some combination of climbing speed and payload.
I expect that any groups that can meet the requirements specification (PDF) [http://www.elevator2010.org/site/documents/climbe r_rulebook.current.pdf ] will be in a good position, regardless of speed or payload.
BTW, I'm actually part of a UBC team building a climber, our website is here: http://www.physics.ubc.ca/~climber/index.html
The other issue not addressed is that the Earth's magnetosphere is neither uniform nor static.
It is significantly compressed on the Sunward side, and elongated on the opposite side, through which any geostationary satellite (and hence space tether) would cross on a 24 hour basis.
Additionally, there is significant displacement as a result of variable solar activity (aside: WindowMaker's 'wmspaceweather' dock app is oddly addictive). I believe other events can create flux as well, both external and internal to the Earth.
Given the length of the tether, even minor effects will be significantly magnified.
Nothing remotely of this scale has been attempted. Structures vastly smaller than this scale have had pronounced effects. This includes both tethered satellites, and earth-based power grids, and both have experience unexpected catastrophic failures due to widespread magnetic events, natural (again: solar events, magnetosphere flux) and man-made (nuclear blasts).
What part of "gestalt" don't you understand?
Nothing off the top of my head, though several recent solar storm writeups have mentioned disturbances to the Canadian electrical grid, some years back. Google says Quebec, 1989.
What part of "gestalt" don't you understand?