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Continued Success for Space Elevator Tests
Jacki O writes "According to their Web site the Space Elevator company Lifport recently managed to get their platform and climbing robot to the mile-high mark over the Arizona desert." From the announcement: "A revolutionary way to send cargo into space, the LiftPort Space Elevator will consist of a carbon nanotube composite ribbon eventually stretching some 62,000 miles from earth to space. The LiftPort Space Elevator will be anchored to an offshore sea platform near the equator in the Pacific Ocean, and to a small man-made counterweight in space. Mechanical lifters are expected to move up and down the ribbon, carrying such items as people, satellites and solar power systems into space."
I stood outside my door this morning in Flagstaff, which is 6200 feet above the Arizona desert.
"Made up/misattributed quote that makes me look smart. I am on
The robot only made it around 1500 feet. The cable was a mile long.
I should have asked this before, but does anyone know how we plan to keep this space elevator up? Also, if it's connected to nothing, then I suppose it isn't very useful for getting items to the moon? Unless of course, the items come prepacked with some sort of mobility enhancing functions.
What day is it? Could you please tell me?
...but it seems like the climber is the easy-ish part of a space elevator. If they were doing work with the carbon nanotubes, I'd be much more impressed.
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A little progress is better than no progress.
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The article said that the platform (held up by baloons) at the end of the teather was a mile up. The climbing device reached 1500 feet, 500 feet further than previous attempts, but still quite a bit short of a mile.
I'm out of my mind right now, but feel free to leave a message.....
I think the theory for this method of transportation was disproved by Wile E Coyote a few years ago.
I've read Gunnm, these space elevators can only lead to a power struggle between the elites at the top of the tower and the service people at the bottom (with a few crafty middle men getting rich transporting the goods!) http://en.wikipedia.org/wiki/Battle_Angel/
#include "forums.h"
int main() {while (bollox) postcount++;}
So, are they in the mile high club now?
I'm just wondering, won't these things become a lightning magnet? You say it can be grounded, but what happens when these things stretch into higher parts of the atmosphere with more ions flying around?
For those who have not experienced this particular pleasure: the obligatory Wikipedia reference.
This is just a meaningless press release meant to drumm up publicity.
The tough thing in building a space elevator is fabricating the Carbon Nanotube ribbon. Making the robots that move up and down the ribbon is relatively simple by comparison.
A space bird.
Every year during my review, I just pray the words "slashdot.org" aren't mentioned.
Seriously, what does the robot on, what type of power supply does the robot have? It only made it 1500' on a mile long cable. Is that because it's energy supply ran out? Science fiction writers usually say ground based "lasers" or "microwave transmitters" but is that more feasible than 62,000 miles of carbon nanotubing?
The platform, a proprietary system that the company has named "HALE" (High Altitude Long Endurance), was secured in place by an arrangement of high altitude balloons, which were also used to launch it
Uhm, how useful will this be when they try to extend the elevator outside the atmosphere? Presumably, they have alternative methods worked out for stabilizing the zero-gravity portions, but somehow, Space Elevator == balloons is not nearly as exciting as Space Elevator == really cool new future technology.
I'll be excited when I can take the Space Elevator up to my penthouse suite at Hotel LaGrange. Unless, of course, I look out and see there are freaking balloons still involved.
...sometimes, in order to hurt someone very badly, you have to tell that person terrible lies. - PA
damn units...
The platform, a proprietary system that the company has named "HALE"
Oh come on, they're just asking for it.
great, 1 mile down, 62,000 miles to go.
Hey I'm at the $1,000 mark now, does that mean I'm closing in on $62,000,000??
sorry guess i'm just a pessismist today, but going 1/62000th of the total distance doesnt exactly sound like "continued success" to me, maybe "progress" but not success...
my karma will be here long after I'm gone
Regardless of how many descriptions of a space elevator I read, I can not grasp a visual of the process. Anyone have a video of something like the post topic?
Bury me in mashed potatoes.
61,999 to go. While it's nice to know that they're working on it, this may take a little while before it's even close to useable.
Someone save me from this sanity.
...won't it whiplash and kill people all over the world?
Mac OS X and Windows XP working side by side to fight back the night.
the LiftPort Space Elevator will consist of a carbon nanotube composite ribbon eventually stretching some 62,000 miles from earth to space.
Is there any type of "backup" system in case a portion of the ribbon breaks?
I assume the way this works is that the end goes so far out that the inertia of the Earth spinning keeps the rope taut... but if a small part of that 62k mile ribbon breaks... the thing gets shot into space.
It doesn't seem viable to just have one long ribbon going up to space... seems too prone to problems. (an expensive problem!)
...when they extend that thing if the moon gets nervous?
The race isn't always to the swift... but that's the way to bet!
Sweet, they are 1/62,000th of the way there!
According to their Web site the Space Elevator company Lifport recently managed to get their platform and climbing robot to the mile-high mark over the Arizona desert.
In other news today, Denver-based Space Elevator company Black Shaft Industries have succeeded in achieving a height of 35 feet with their platform and climber, still easily besting their rivals Lifport. "We had a head start," acknowledges Chief Engineer, Michael Wesznick, "but our elevator didn't really need it. Plus, it has a cooler name." Wesznick went on to claim, that the elevator in question (named "Darth-Vator" to those of you who were wondering) will be the "father of all other space elevators", and, adding to this reporter's confustion, will at some point in the future "betray the Emperor to save it's son's life." Personally, I'm rooting for Lifport.
There's got to be a typo in that. http://en.wikipedia.org/wiki/Earth's_atmosphere [Wikipedia] says that people who travel 50 miles up are considered astronauts, which sounds like a much more reasonable number to me. Heck, the Earth's radius is less than 6400 km, which is a lot less than 62000 miles. Probably got some extra 0's in there, or posted the wrong units.
Yes, I appreciated that one too. Gimme a break! 62,000 miles. The Earth is only 22,000 miles in circumference! They also noted that they achieved "stationery" position. Does that mean that they stacked it on a huge pile of paper?
Now, what happens when some foreign country lobs a small nuke into orbit, pushing the counterweight back towards earth, and all that carbon nanotube/nanofiber/monofilament comes crashing down to earth?
If I recall correctly, there was a book published, where an event like this occured (fiction of course), yet the outcome was pools of bucky ball forming in impact zones, plus all the damage of that much material impacting the earth (the carbon material being heat resistant enough to not burn up during re-entry).
Just a thought...
Who is general failure, and why is he reading my hard drive?
You mean like this?
(Sorry, it's angelfire and might notlike hot-linking, but if you enter the URL directly, it ought to work...)
A preposition is a terrible thing to end a sentence with.
No. 62 miles is the completely arbitrary definition of "space", but a space elevator that ended at that altitude would simply fall back down. By necessity, the center of mass (radially from the surface of the Earth) must be at or near geosynchronous orbit, so it naturally remains centered over its ground anchor. Geosynchronous orbit is at 22,241 miles above sea level. So, by gradually tapering the cable and extending it past GEO, the center of mass ends up there. Alternatively, you can have a large mass like a captured asteroid or something as an anchor just on the far side of GEO, although you should also have some counterweights you can move around on the cable to keep the center of mass in the right place as a load moves up from the surface. Additionally, keeping the center of mass just a little bit further out that necessary ensures that the space elevator will have just enough tension to keep it taut, giving the climbers an easier job.
Why don't we just build a 500 mile high pyramid of some description? And maybe run a ramp up it, and a pulley system maybe so we can use very simple earthbound techniques to get projectiles to an incredible speed before liftoff? Alternately, its surely easier and cheaper to get a launch from 500 miles up, or put the tail end of a space elevator there. And we could do it with existing technology easily. Its like the question, if there were stairs going to the moon, could you walk it... the answer to that one is yes.
What he can't kill, he has sex on. Trent.
Yah. That's the point. The cable goes to geosynchronous orbit.
Yes. That's long. But it's not as insane as you might think. The biggest concern is the tensile strength of the cable itself. Once (if, and it's a tough "if") that gets solved, it's just a matter of a really really big spool of cable.
Don't get me wrong. It's still moderately insane. It'll be #1 on the Discovery Channel's modern engineering marvels if it's completed - by a large margin. But it's not completely ridiculous insane.
Wouldn't this rule out use of al non-geostationary equatorial orbits at any altitude less than or equal to the altitude of the anchor, since it would eventually collide with the tether?
Of course I'm not sure what use a non-geostationary polar orbit is.
The Earth's gravity field extends way beyond the main bulk of it's atmosphere. You have to go much more than 50 miles to get to a point where you can have an orbital velocity that is balanced against the Earth's pull but be circling at the speed which the planet rotates.
Have you looked at their image gallery?
Their prototypes are made of bloody lego!
"Consider how lucky you are that life has been good to you so far. Alternatively, if life hasn't been good to you so far
The downside would be that the end of the tether attached to the orbital station would set up a drag in the Earth's atmosphere
No, it wouldn't. It's in a geostationary orbit, so it's moving at the same speed the earth's surface is. There wouldn't be any relative velocity, so no drag.
--MarkusQ
Despite all the technicalities that many Slashdot users like to point out I think its great that people are testing methods to get into space that don't involve lighting a giant bottle rocket.
For some reason I refuse to use either spell check or the spacebar properly.
Their PR people are just... well, they have no very uplifting imagination when it comes to wordsmith skills.
When we reach near-lightspeed, when it's convenient to get a counterweight for this "elevator", and someone's stupid enough to make it...it will barely break the top 10 marvels. Probably wont be done on Earth. As mentioned in other posts, you have to be 22k miles (not 62) above the Earth to keep a space elevator's center of mass in geo-sync so that it doesnt fall back to the planet. It's completely and ridiculously insane.
Often wrong but never in doubt.
I am Jack9.
Everyone knows me.
I mean, we are all geeks and nerds, so we of all people should support this science.
Its something I will have to see to believe, but in theory, it all sounds quite practical. The only "IF" in the whole concept is if we can actually manufacture a carbon nanotube ribbon 62,000 miles long and how exactly are we going to get it in place. A smaller if is whether we should actually do it. Something falling out of the sky with 62,000miles of cord attached to it could mess things up around the equator pretty bad. (BTW, read the Red Mars, Green Mars, Blue Mars trilogy)
I think this is one of those things that while we try and pursue it, even if its natural end is failure, much new technology and science will result from it. An effective, cheap and efficient way to generating carbon nanotube structures is what I hope will result from the endeavour, if not an actual space elevator. It just seems they are working on the elevator part before working on the part that will actually make the concept work.
I haven't thought of anything clever to put here, but then again most of you haven't either.
Does the firm have any ideas on how to avoid tremendous death and destruction if this immensely long cable were to fall to the Earth, possibly hitting certain areas twice as badly if it were long enough to wrap more than once around? Kim Stanley Robinson's Red Mars has an especially disconcerting description of this happening. This sort of technology is exciting, I just hope enough attention is being paid to safety.
Is this 'space elevator' going to be called a 'space lift' in the UK?
Only another 99.99954% of the way to go! . Wohooo!
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But who knows, maybe they do mean 62,000 miles? I thought the elevator's main purpose was to get things in and out of just the atmosphere, as to avoid all the problems with expensive and dangerous rocket launches and dangerous re-entries.
We don't use rocket to get above the atmosphere. Planes can pretty much do that. Balloons can (and regularly do) do that. That's the easy part.
We use rockets to get velocity, because you need a ridiculous velocity in order to actually orbit the Earth at a low height.
You do not, however, need a ridiculous velocity in order to orbit at a very, very high height. At geosynchronous orbit, you need no velocity, because you've already got the speed from the Earth's rotation.
So yes, they do mean 62,000 miles (100,000 km). And the benefits you get from a cable like that are insane. Costs/pound to launch things into space become negligible. Transit to the Moon becomes cheap and fast, because the end of the cable is actually moving faster than orbital velocity.
In fact, if you climbed all the way to the end of the cable, and let go with good timing, you'd end up past Jupiter (and on a direct trajectory, too, no mucking about in Lagrange points).
Yes, it's moderately insane. Yes, it's ridiculously difficult. But it would also end up being one of the biggest changes in human industry that has ever occurred. Space solar power plants beaming down power becomes feasible. Large-scale structures built in space become easy.
Plus, once we get the technology, we can build them on other planets as well. The Moon. Mars. It basically eliminates almost all of the serious difficulties of space flight.
You don't need a counterweight. Counterweights are pretty much counterproductive - it's cheaper just to make the cable longer.
Oddly enough, we don't know how to get to near light speed. We do have significant engineering information on how to build a space elevator. Go out and read it. If you think it's as difficult as reaching near light speed, or moving an asteroid, you're crazy.
/ \ Carbon nanotube cable
| Earth |-----------o----------------O <- Counterweight
| | ^Lifter
\ /
\-----/
Counterweight goes around Earth at the same speed as the Earth rotates, keeping the cable taut. Stuff moves up and down cable by Lifter.
HTH
I want to play Free Market with a drowning Libertarian.
There are other ways to get into space without extending a strucuture beyond geosynchronous orbit. Check out launch loop and this wikipedia page.
By necessity, the center of mass (radially from the surface of the Earth) must be at or near geosynchronous orbit, so it naturally remains centered over its ground anchor
For the simple case, yes. But (IIRC) Robert Forward proposed a modified concept that utilized solar sails to stabalize the orbit and allow for them to be in other orbits. Or it may have just allowed for non-equatorial placement, or both -- I don't recall exactly and I'm certainly not a rocket scientist/orbital mechanics expert.
Why did I suddenly think of the Atlas Tower from Front Mission when I heard that they'd be using this thing to transport solar power systems into space?
Also, will a war with giant robots break out prior to and again immediately after it's completion?
I am way rusty on space elevator facts, but I believe it must go thru the geostationary point, which is 23K miles up, and far enough beyond to counterbalance it. I couldn't even tell you now if that 23K miles is from earth's surface or center.
Infuriate left and right
Think Bob Dole.
Hate to reply to myself, but when you have an idea... Eh you could even put a couple of hundred pulleys going up one side, with a couple of nuclear power stations buried in there to power them (and internal elevators going up and down, as well as any other power requirements). Surely you could reach escape velocity with ease and en masse by using very cost effective nuclear power like this... and also it could be based in a sea somewhere, so returning vessels could splash down nearby. Now that would be a serious spaceport! :D And all readily doable and not making the greens shriek or anything (except for a 500 mile by 300 mile strip of ocean that we weren't using anyway :D). Or if that doesn't sit right, the equatorial third world nation of choice would be more than happy to make itself richer than America and Europe combined by hosting the world's first true spaceport...
What he can't kill, he has sex on. Trent.
The idea is to build it from orbit. You build in both directions simultaneously to keep it balanced.
Infuriate left and right
Some people have suggested a powered cable, but I'd wonder about that and required travelling distance. Pumping power over the distance of cable required to reach an object in orbit sounds like a fair distance to me. How far do power companies, etc usually transmit from a given power station?
It will be all giddy.... Until a frecking huuuuuge space-alien comes about, rolls the elevator once around earth and uses it as huge leash to go around with her new found pet rock. YOU FEEL LIKE FLEA ON A PET-ROCKS FUR YET?
I think this is an error. I believe they meant 62 Miles which is considered to be the "edge" of space.
Im not here now... Im out KILLING pepperoni
1500 down, only 321158500 to go.
Seems like a scaled up version of this might be useful in an industrial capacity without going all of the way to space.
Walmart has what, like 900 distribution centers in the USA? Figure that many of them are 100 miles or less apart.
An automated glider holding a pallette could be launched from a 10 mile high elevator and glide with a 10:1 glide ratio to an adjacent distribution center. Given safe landing points at 25, 50, and 75 miles, it would be relatively safe, and Walmart could move goods throughout the USA by lifting the glider, releasing it, letting it land, and lifting it again.
Run it on solar power, and it's pollution free.
The US Postal service, FedEx ground, and UPS ground could send mail this way too.
It's the Elevator-net!
The world will not get better through technology. We must seek to be better people.
This question is rather hypothetical, but what happens if these things are capable of launching thousands of tonnes of cargo in space. Will the Earth spin slower (albeit just little slower) due to loss of the mass?
It's like sitting on a spinning office-chair and then releasing a large weight. The chair will spin slower (I think).
Someday, I expect tonnes of valuable goods created with resources from "out there" may find their way down here too.
Personally, I am not the least bit worried about it.
This issue is a bit more complicated than you think.
Any thoughts on the ability to connect generators to the end that capture the vast amounts of solar radiation filtered out by our atmosphere and convert it to electricity? Could the carbon nanotubes, or an embedded superconductive wire transfer it back to Earth? Seems like a very eco-friendly solution (other than the cable snapping and decapitating half the planet ;) )...
That opening that route might let something in?
Sorry for the stupid comment but the link to the story was dead and I just thought...
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what kind of mods I get for this...
/. put it is a much better idea.
/.'r made a comment about the impact on the Earth's rotational speed being affected. I think that would be a pretty important concern.
It is a BAD idea. It is a waste of time and will lead to a severe accident.
Searching for a better "bottle rocket" as some one on
Another
Given that we are concerned about the "slight" change in our ecosystem (Global) by Global Warming. Wouldn't it make sense that a slight change in the rotational velocity of our planet have a dramatic affect?
Many ask can we do it... I ask should we do it? I don't see why we should.
How many hippies does it take to keep a space elevator up?
Seven. One to stay on earth as ground control. One to make veggie burritos. One to flip the tape. And four to get so high they never come down.
The last time humanity did this, didn't we end up unable to speak to one another?
Not only is that far beyond geosync, but thats over 15% of the way to the moon... its a strange coincidence its 1000 times 62 miles which is considered the "edge" of space. Perhaps this is an error even though 62 miles whould not generally be considered "far enough"?
Im not here now... Im out KILLING pepperoni
A guy gets on at the bottom and punches all the buttons. For 100,000 km your're thinking, "asshole!"
Give a man a fish and you have fed him for today. Teach a man to fish, and he'll say "WHERE'S MY FISH, YOU IDIOT?"
Achieving the strength needed with nanotubes is one part of the problem. I believe there are several companies working on that, because even if the space elevator never comes to fruition, high strength composites will probably pay for all the research that goes into them.
I'm fairly convinced that power is a bigger problem. How far does your car go one tank of gas? 400-500 miles off of maybe 20 gallons. To get to geosynchronous orbit climbing a cable you have to go 22,000 miles (or is it 18,000...I can never remember if that includes the earth's radius), that's 55 times as far. But you can't just assume you can scale that 1100 gallons of fuel. First (as every rocket enthusiast knows), you burn a lot of fuel lifting your fuel. Second, the mileage you get in your SUV almost entirely from overcoming friction. In the space elevator, you have to develop potential energy...a lot of it. It quickly becomes clear that on onboard power supply is not feasible.
Most of the discussion I've heard revolves around power beaming with either a laser or a big microwave antenna. From 22,000 miles away, this has to hit a collector small enough to fit on the climber, but big enough to convert several hundred kilowatts of power into electricity. I'm not aware of any current application anywhere near this scale.
A space elevator is theoretically feasible, but the challenges are far from trivial. I laugh at people who suggest one can be built starting today for $10 billion. Some of the estimates I've heard put the cost of developing all the technology for and building the first elevator at several $trillion, or equivalent to the federal government's entire annual budget. Of course, if we ever get one up, subsequent elevators are far cheaper.
If balloons can get us out of the atmosphere, why not use balloons to make a very fast form of transit that is made possible by having very little air friction?
In order to stay up, this thing's center of mass has to be at the geostationary orbit altitude, which is 42245 km.
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Slashdot. Such a mixed blessing.
Display some adaptability.
If balloons can get us out of the atmosphere
They do.
why not use balloons to make a very fast form of transit that is made possible by having very little air friction?
Because you still have to go up, and then down. The economics of something like that completely don't work.
Plus, people didn't pay to travel in a supersonic plane, much less anything faster. Conventional travel is fast enough.
As long as they keep saying it is for moving stuff to space they might finish this thing, otherwise they're gonna start talking gibberish.
And their web server can't handle a slashdotting? And we expect them to build this thing?
My other sig is a knife wound.
61999 miles to go...
Instead of having a robot climb the tether just have a pully on both ends. Sure, the pully wheels may need to be large to accomodate bending the rope without stressing it. But with this idea all you have to do is build a latch mechanism that you can remotely unlatch once it is it's proper orbit. All the climing power would be in the motorized earth-based pully wheel.
What do you think about that?
wow, I've never seen a score 5 post with so many completely wrong comments in it.
Planes and Balloons can't get above the atmosphere, because they both need an atmosphere in order to work. Jet engines need some sort of air around them in order to generate push and lift. Balloons rely on the air inside them being lighter than the air outside them. No air outside means no lift. We use rockets because they are the only way of truly leaving Earth's atmosphere. They are also the only way we can get out of the influence of Earth's gravity. If our atmosphere extended much higher, in theory, we could take a plane to the moon, simply by building our velocity high enough to escape velocity while in the atmosphere and letting inertia take us out. However, the jet plane is bounded by the atmosphere, because it needs atmosphere to move.
Geosynchronous orbit means that it orbits with a period of exactly 24 hours. There's nothing "special" about Geosynchronous orbit which means you can "get the velocity from the Earth". You DO have velocity. From an observer on Earth, it would look like you're standing still, but it still takes a lot of energy to get there. Once in orbit, of course, it doesn't require energy, but NOTHING in orbit requires energy
The idea of a long cable is not to get us out of the atmosphere, but to get us far away from the pull of Earth's gravity. If you climbed all the way to the end of the cable and let go, given you had escape velocity, you would get past anywhere. The idea is at that height, escape velocity is negligable. The idea is it takes little effort to leave Earth's Gravity at that height
being vague is almost as cool as doing that other thing...
from the NS artical
"The idea is to build the actual elevator's ribbon from ultra-strong carbon nanotube composites and to have solar-powered lifters carry 100 tonnes of cargo into space once a week, 50 times a year."
ok so say i buy the idea that we create a cable that extends 62,000 miles. and say i buy the idea that we develop a platform to climb it.
but comeon 62,000 miles once a week! its going to have to climb it at an avg rate of 369 mph! twice that if it plans to get up AND down in a week!
I suppose once you get out of most of the atomosphere you could go rocket propelled but still!
And particularly so, when they are operating on such a shoestring budget that they can't afford to spellcheck the release.
If they're overlooking something obvious like that, what else are they forgetting?
From the second paragraph:
"In this phase of testing, conducted earlier this month in Arizona, LiftPort successfully launched an observation and communication platform a full mile in the air and maintained it in a stationery position for more than six hours while robotic lifters climbed up and down a ribbon attached to the platform."
"Politicians are interested in people. Not that this is always a virtue. Fleas are interested in dogs." P.J. O'Rourke
...apparently.
:o)
Seriously, space elevators are nothing new at all. Science fiction has been all over this for decades. One poster referred to an Analog article about the math and materials involved. Popular Science has done similar articles.
This (building a viable space elevator) is quite feasible. No, the materials aren't there yet and it won't be easy.
Neither was Apollo, yet nearly FORTY FREAKIN YEARS AGO, 12 (18 counting the Command Module pilots who stayed in orbit) people from Earth went to the moon and back in Apollo spacecraft (11 through 17 with 13 aborting and becoming a Tom Hanks movie)
How good was the design? Well, so good that the current NASA Director has stated that they can't come up with a better one. So, the "new" CEV spacecraft slated for missions to the moon...for as long as 6 months at a time....and then Mars is basically an updated Apollo capsule.
The point is that if you go back and read popular media after JFK's speech that "...we will land a man on the moon before the end of the decade", you'll see very smart people listing all sorts of reasons it couldn't be done.
Even further back, Arthur C. Clarke proposed what was to become communication satellites. The naysayers were legion. Geez, glad DirecTV didn't listen.
Basically, if a viable space elevator can be built, it will make the cost of moving people and material to LEO cheaper than flying from NYC to LA.
The economics will drive the technology and it will happen, probably in our lifetimes. I figure 20 years with 40 years as an outside figure. It just makes too much sense.
I am my own gestalt.
.. woaaaah. Seriously, the reason for this companies existence is to suck up grant money and get attention. They aren't doing anything remotely relevant to space elevator research. I'm going to pretend I never even read this article and move on with my life. There are scientists and organizations doing serious work on carbon nano tubes and space elevators, and this is not one of them.
Sig: I stole this sig.
that there's a company with this as their goal. But, the robot climber is not the hard part at all. The hard part is the carbon nanotube tensile strength issue. Even having a robot climb a mile (or as some have said 1500 feet) is nothing special. We have the technology to do this already. A 1 mile cable is also nothing, bridges have this already. They're talking about a 62000 mile cable. I'd be more impressed if they told me that they had a 1 meter nanotube cable that has the tensile strength of 60 gPA. That would at least be the building block for being able to build the space elevator. But, this gets headlines even though it's meaningless.
No Sigs!
As much as the idea of a Space Elevator thrills me, the jaded side of me says this is just asking for trouble. It'll end up being way too big and tempting of a target for the next fanatical group. All that money and resources, taken down by a single looney with a bomb. Or a country/group group with a missile, maybe nuclear tipped (Anti-missile defense? Naw, we don't need to develop anything like that). Can't wait to see countries start arguing over control of the elevator, or some whacko regime take it out so that no one can have it.
No security is ever perfect, after all.
If so many people are worried about safety they could install like a spring retraction device. Like my ID card at work.. its attached to a reel thats spring loaded. When I let go it coils back up in the clip. So run a wire up with the nan-cable and if the wire snaps retract the cable. the weight in space floats off and the cable is retracted into the platform. No more whiplashing the earth.
Now if they can just get the climber to float, they might be able to ink a joint marketing deal with Ivory soap.
There is no right to feel safe thru security vaudeville at the expense of everyone's freedom, privacy and tax money.
And the benefits you get from a cable like that are insane. Costs/pound to launch things into space become negligible. Transit to the Moon becomes cheap and fast, because the end of the cable is actually moving faster than orbital velocity.
Neglible cost to get mass into space...really?
And how do you know this? It has not been built yet. This kind of speculation sounds good in a sales pitch, but probably are not all that realistic. I'll be happy to admit I was wrong if all the hype turns out to be true in about 50 years, but right now, I think a fair amount of honest skeptism is in order.
Computational Chemistry products and services.
Still, too many people have the mind-set of "don't spend my money on <insert technology here> unless you can show me the benefit right now". Fine - those stupid enough to feel that way also tend to be stupid enough to believe whatever wizards like us tell 'em! So they get pissed when <technology> fails to deliver on its promise? Too bad! We'll get 'em back with spinoff technologies.
Carbon nanotubes will never get an elevator into space? Okay, but when we can grow the little beggars a mile long, we can rewire much of our infrastructure with 'em - massive bandwidth for everybody! The unwashed masses will forget that we never got them an elevator ride into orbit when they see our new petaflop PC's communicating on the world wide web at 10gb-base-txx (think: pr0n. The masses love that).
Don't think the research will pan out? Maybe not as predicted, but soon as we learn how to do something new and useful, we will - never mind if it wasn't what we were going for initially!
IAARRS (I am a retired rocket scientist, and have participated in a NASA
Space Elevator workshop, and been on a science panel with one of the Liftport
guys - I guess that makes me a relative expert)
A tower going up from the ground meeting a cable coming down from orbit is
more efficent than a cable going all the way to the ground, if, and this is
important, the strength of the cable is substantially less than the depth
of the earth's gravity well.
Here's why: As you build a longer cable or a taller column of constant area
under gravity, the stress gets higher. In a column the maximum stress is at
the bottom, and in a cable it is at the top. Eventually you exceed the
strength of the material.
The Earth's gravity well is equal to one gee times the radius of the planet
= 6,378 km. A space elevator is centered at GEO, which is 97% of the way out
of the Earth's gravity well, so we need to span 6,167 km at one gee.
The strongest readily available carbon fiber that is not made of nanotubes
is about 1 million psi in strength. It has a density of 0.067 lb/in^3, so
if you had a cable 15 million inches long under one gee, it would be at the
limit of it's strength. 15 megainches = 381 km, which is a factor of 15
below what we need.
You can build towers or cables longer than the strength limit if you make
them progressively wider to keep the stress below the limit of the material.
Each 15 inches of length in the cable above adds one millionth to the stress,
therefore the area has to increase by one millionth. Over a 381 km length,
the area of the cable increases by a factor of e (2.718...). This length,
found by dividing strength by the density of the material, is called the
scale length. If you have 16.2 scale length to cover (6167/381), your
cable area increases by e^16.2 = ~10 million.
A graphite/epoxy composite is needed for a tower. Bare fibers are okay in
tension, but you need to stiffen them for a compression structure. Typically
using the same fibers, the composite will be 30% as strong in compression as
the bare fibers are in tension. Now assume you build a tower up and a cable
down with the same area ratios from bottom to top. The tower's scale height
is 114 km, so the combined scale heights for the tower + cable = 495 km.
Now you need 6167/495 = 12.5 scale heights. e^12.5 = ~250,000, which is
a factor of 40 improvement.
If you have carbon nanotube cable which has, say a 10 million psi strength,
your scale length is 3810 km, and your area only needs to grow by a factor
of 5 from bottom to top, so the reduction possible by using a tower is much
less helpful. Of course, we are not making 10 million psi cable in useful
quantities yet.
Daniel
The reason why the costs are negigible is that while the fixed costs required to create the elevator may be (and probably will be) enormous, the marginal cost of using it will be quite small. Those costs will probably be composed primarily of labor to maintain it and power to the climber.
.
There may be some lurking marginal cost nobody has considered, or on the other hand the operational lifetime of an elevator might be so short that the fixed costs never get amortized that well, but barring those possibilities, it's reasonable to assume that with a space elevator, getting into space will be pretty cheap.
BTW: geosync orbit is 22,000 miles, not 62,000 miles: http://en.wikipedia.org/wiki/Geosynchronous_orbit
If your bitterest enemies are people who hack the heads off civilians, then I would say you're doing something right.
I was on digg earlier, (sorry /.) and was seriously taken aback by the ignorance of the geek masses there.
I never thought someone who spends time looking at cutting edge science would have problems concieving of the validity of the space elevator. The tensile strength of the filament has been built to about 1/3 the necessary strength in less than 3 years. A method is in process to produce the filament en-mass when it gets up to strength, and NASA is backing the robot climber contest. every aspect of the project is being chipped away at relentlessly (and with notable progress). The location in the mid-pacific has been scoped out. (few storms, intl waters, far far away from anything but more pacific ocean, etc.)
There are preliminary designs for the sea platform. The counterweight as currently concieved will consist of a.) the least mass possible bunch of research oriented electronica, and b.)the first hundred or so test run ballasts.
These people are serious. check before scoffing.
... the company sets not only the year but the date hour minute and second that they are going to do something that they don't know can be done.
COUNTDOWN TO LIFT: April 12, 2018 12 years, 58 days, 6 hours, 25 minutes, 49 seconds
Is buying a Harley Davidson as your first motorcycle since you were 16 at age 49 a midlife crisis issue?
What a meaningless test. Testing elevator robots for a space elevator when you do not have the carbon tubes to develop it is like testing seat cushions for an automobile when you do not have the internal combustion engine.
... the important research at this point has to be done at the molecular level and we are very far off from what we need. So far the longest carbon nanotube ever created is 0.4 cm long, and that is quite far off from 65 000 miles.
The most challenging thing about a space elevator is the "carbon nanotube composite ribbon". Yet all these companies that say that they are about to build a space elevator not only have not developped one but are not even trying to, instead they are doing silly demonstrations and studies which just assume that somebody else will develop a 65 000 mile (!!!) long carbon fibre rope anytime now.
So do not get excited, all of these tests are silly publicity stunts
By the way notice how the press release that slashdot linked to slyly avoids the issue of what kind of rope they are using for the testing. When they describe the space elevator in the abstract they say that it will require "a carbon nanotube composite ribbon", when they describe their own test they say they used "a ribbon". A little misleading, some might say.
gee, just think of the things we could build if we wisely spent our money
instead we waste it on selfish unsatisfying consumerism
go figure
Words to men, as air to birds.
It's always great seeing science fiction attempted.
BTW, it's also a great read.
I word things very carefully. Read it again. I said "planes can pretty much do that." I was actually thinking about commercial airlines, which fly above 72% of the atmosphere.
But, of course, there's this nugget from Wikipedia:
Balloons typically reach altitudes of 100K feet, which is above all but a fraction of a percent (it's a few Torr).
simply by building our velocity high enough to escape velocity while in the atmosphere and letting inertia take us out.
Ignoring that whole "air resistance" and "speed of sound" thing.
And curiously, if it wasn't for those two things, we could do that right now.
We use rockets for velocity, not altitude. If you doubt me, consider that the Space Shuttle's two solid rocket boosters shut off at lower altitudes than the X-15. Why don't we use a jet to boost the Shuttle to that altitude? Because the SRBs get the Shuttle to a much, much higher speed.
There's nothing "special" about Geosynchronous orbit which means you can "get the velocity from the Earth".
I get velocity from the Earth all the time. It's called standing on the ground. (Curiously enough, if I didn't, I would start flowing in these little circly patterns, called Hadley cells, which are what happens when you have a viscous medium gravitationally sitting on top of a rotating sphere. If the atmosphere extended enough, it essentially wouldn't be rotating.)
That's what special about geosynchronous orbit. Orbital velocity is slow enough that I can use the Earth's rotation to supply it.
You DO have velocity.
Which I got... from the Earth. Like, when a plane lands, after heading west, how the Earth speeds it up in a matter of seconds?
The idea is at that height, escape velocity is negligable.
It's not "negligible" - it's two thousand miles an hour (curiously, roughly 1 km/s). It's just neglible in the rotating frame of the Earth.
Point one. Planes generate lift by having a wing shaped in such a way that air rushing over the top surface has less pressure than the air rushing below the bottom surface. No atmosphere? No lift. No lift? Plane goes down. Or if you get up high enough, the atmosphere gets thin enough that you don't get much lift ... and planes need a hell of a lot of lift to stay up.
Point two. Balloons generate lift by having the gas inside the balloon at a lower density than that of the atmosphere. Balloon goes up to high levels, atmosphere thins out. Eventually, the balloon and the atmosphere will be at equilibrium. There's no way a balloon can go above that point, let alone past the atmosphere.
Now, on to the big mistake you've made:
Here's a free clue for you. The Earth's diameter is approximately 12,700 km (actually a bit more, but the number's good enough for my purposes.) Geosync orbit is at 35,786 km above the earth's surface.The Earth rotates once every 24 hours (again, approximately). pi * d gives a distance covered of around about 40,000 km. That's a speed (not a velocity; velocity has a direction) of 1,666 kph. Make a note of that figure.
Geosync orbit is at a radius of 35,786 + (12700 / 2) km, or about 42,136 km. This is from the centre of the planet. At that radius, to go around the Earth once in 24 hours, keeping you above the same point on the rotating surface below, you have to travel 132,374 km -- at a speed of 5,515 kph (approximately). That, for the mathematically challenged, is three times the speed of an object on the planet's surface.
Tell me again that you don't need a speed boost to get to geosync orbit, and I'll laugh in your face.
But wait, you say! The space elevator is centred at geosync orbit! Where does an object climbing the cable get its speed as it climbs? The answer's easy: as it climbs, the cable puts pressure on the planet. The planet slows down a miniscule amount, and transfers the momentum lost to the climbing object. Because the climbing object's mass is a miniscule fraction of the mass of the planet, the slowing down is unnoticeable.
Sigh. Clueless people, spouting off as if they know what they're talking about, and other clueless people fall for it. Feel free to check my maths, bearing in mind there's a bit of rounding in there which doesn't affect the significance of the result ...
"Transit to the Moon becomes cheap and fast"
Maybe fast once you're up the cable. You still basically have to drive 20 - 30 thousand miles (straight up) before you can let go. I get antsy driving from D.C. to PA, much less than driving the circumference of the earth.
By necessity, the center of mass (radially from the surface of the Earth) must be at or near geosynchronous orbit, so it naturally remains centered over its ground anchor
For the simple case, yes. But (IIRC) Robert Forward proposed a modified concept that utilized solar sails to stabalize the orbit and allow for them to be in other orbits.
Well, sure. His point was that given adequate propulsion, one could put a tether anywhere. There is nothing magical about orbits, and there is just as much gravity in orbit as there is on earth (small inverse-squared effects notwithstanding). When in orbit, your horizontal velocity is perfectly tuned so that by the time you have fallen 10 feet vertically, you have moved far enough horizontally that the curve of the Earth's surface has also dropped ten feet. Through constant freefall, you stay the same distance from the Earth all through your circular orbit.
The difference with a space elevator is that the geosyncronous orbit allows for the elevator to stay motionless with respect to the ground.
If you wanted to have a tether in a different orbit, but still motionless with respect to the ground, then you have to alter gravity slightly. This can be accomplished by adding thrust, either against gravity (for orbits inside GEO) or with it (for orbits outside GEO). If your space elevator had rockets constantly firing down toward the Earth, then it would experience less than the standard 9.81 m/s^2 gravity, and it's "geosyncronous" orbit would be lower. This could also be accomplished by cleverly pointing a solar sail, or using small pellets at high velocity, or whatever. In fact, Liftport did this with their balloons. The bouyancy of the balloon provided a force against the pull of gravity, and the pull was enough that a geosyncronous orbit altitude of one mile was sufficient. (It's not a real orbit, of course, but it's a nice neat analogy.) Whether this thrust is "keeping you aloft" or "altering the pull of gravity" is all a matter of reference frame.
This thrust proposal would not work for non-equatorial orbits, however, if the spacecraft is in a true orbit (and not an analogous one, like the balloon). All circular orbits have to traverse a Great Circle around the planet; the center of the orbit would be at the center of the planet. So if you were standing at about 40 degrees north latitude and started your circular geosyncronous orbit, then 12 hours later the spacecraft would be at 40 degrees south latitude, along the same longitude. It would alternate back and forth between those two points on every rotation of the Earth, since the orbit itself would have to be tilted 40 degrees from the equator. This is the difference between "geosyncronous orbit" (period of 24 hours, possible precession) and "geostationary orbit" (period of 24 hours and equatorial, so there's no precession). Most commercial geosyncronous orbits are only tilted by a small amount, so if you are south of (or north of, in the southern hemisphere) a certain latitude, the satellite never dips below the horizon.
For security, the MD5 hash of this message and sig is 09f911029d74e35bd84156c5635688c0.
As of last year, the world record for the longest carbon nanotube was four centimeters. That's about 2 inches, for those of you who are metric impaired.
To get to 62,000 miles (almost 100,000 km), they'll need a cable that's 2,500,000,000 times longer than what they have today.
Wake me up when the economic costs of the project is only a ten times what the public is willing to pay for; not when the engineering requires are 2.5 billion times what is possible using today's technology.
Assuming Moore's Law holds for making economic, yard wide carbon nanotube ribbon fibers (a generous estimate, given that most techn doesn't follow such a curve), we may have a scientifically viable cable in (at 30 doublings, with one doubling taking 18 months) 45 years.
Add in 20 years to get the politics straightened out (there's no doubt this will be an issue for the entire world to squabble over for at least two decades after it becomes viable, and it's not something I'll ever see in my lifetime.
It takes millions of dollars just to build a 10km bridge. Goodness knows how much a space elevator will cost, but I'd add in a few decades of the international community bickering over who will pay for it, and who'll be liable for damages when something falls off it, long after the majority of countries agree it can be built, and that it's a good idea to build one in the first place.
I'm guessing it will take a century to get this thing built, if it ever does.... I bet we'll see flying cars before we see a space elevator!
IANANWBARS (I am not and never will be a rocket scientist) but how does that impact the pyramid idea? Or is there any bearing on it? I'm not sure I track you...
What he can't kill, he has sex on. Trent.
What a waste of time and money.Maybe SETI sent them bluprints, as a joke.
this being possible in principle. When someone builds a "cable" of a few microns strong enough to support its own weight if scaled to space-elevator size, then I agree, this becomes an engineering problem.
So far, no one has demonstrated that such a cable exists.
What about using a JPAerospace "darksky" station as the bottom end of a tether? It's also vaporware (they have prototypes) on a practical, current scale, but very interesting. THey've proposed launching rockets from the eventual station, it seems a natural for a space elevator that lacks the strength to go to ground.
josh
gigantino.tv - Heavy but weighs nothing.
I said "mostly". Planes, and balloons, get above 99.99% of the atmosphere. The X-15 got to 99.9...lots of 9s... percent of the atmosphere. I'll say it again. We don't use rockets to get above the atmosphere. That's my point.
The Earth rotates once every 24 hours (again, approximately). pi * d gives a distance covered of around about 40,000 km. That's a speed (not a velocity; velocity has a direction) of 1,666 kph.
What's impressive is that you wrote about 4 paragraphs commenting essentially on the fact that I neglected to use the word "angular" in front of velocity.
Hell, you don't even need to reach escape velocity - just build a pyramid 36000km high, hoist stuff slowly up the side, then give it a gentle push!
Alien tourists would come to see the only planet in the galaxy that looks like an ice cream cone...
What part of "a well regulated militia" do you not understand?
This batshit fucking insane +5 troll should be -50,000! One of the best I've seen in a while though. Good job getting people to reply to you as if you're serious!
They want to go up to 62000 miles
;-)
...
They had 1000 feets at the end of september 2005
They have 1500 feets now, a 1.5 times improvement in 4.5 month
According to Google Calculator :
(log((62 000 miles) / (1 500 feet)) / log(1.5)) * (4.5 month) = 11.369675 years
Or the other way round :
1 500 feet * 1.5^((11.37 years) / (4.5 month)) = 62 021.7921 miles
Their countdown : 12 years, 58 days
So, as long as they keep this exponentiel growth, they'll get there
If they have linear growth however, it'll be a while
(((62 000 miles) - (1 500 feet)) / (500 feet)) * (4.5 month) = 245 518.875 years
I have discovered a truly remarkable proof for my post which this sig is too small to contain.
The higher the orbit, the more velocity is needed to maintain orbit. The parent had this correct.
Sure, the angular velocity of an object in geosync is the same as one on the ground, but that means nothing. If you're launching an object to geosync you need a LOT more fuel than getting to low earth orbit, and the height is only a minor aspect of this - the orbital component of the velocity is the main contributor.
The only reason a space elevator is cheap is because it steals momentum from the earth. It has nothing to do with a reduction of the velocity needed to attain orbit...
Why anchor it in the sea if you can gain 10,000ft for free on a mountain top? I guess compared to 62,000 miles that won't be significant, but still couldn't hurt.
Bleah, that last part is wrong. It's like 9000 miles per hour.
The X-15 did just about reach space....but it used rocket motors to achieve that altitude. Planes and balloons do NOT get above "99.9%" of the atmposphere. Do you even have any idea how high up that is? .1% atmosphere is REALLLLLLY high and no plane has gone that high without, guess it, ROCKET propulsion. Planes and balloons require a sufficient amount of atmosphere content and/or pressure to work. .1% atmosphere won't do it for them.
You say: We don't use rockets to get above the atmosphere. That's my point.
How on Earth (no pun intended) can you think this?
WE USE ROCKETS TO GET ABOVE THE ATMOSPHERE
I figure this may sound a little naive, but why can't I put my "space elevator" next to a deep water port like san francisco?
I'm also figuring into this what-if the idea collecting the electricity that is generated from wind friction when this thing starts to work.
..\/
_/\_
has a lesser mass than
/....\
\..../
_\/_
Aside from that, if you build the tower first, you can launch from the tower to build the rope, and start getting significant returns much sooner.
Last of all, it's easier to blow the second example free in a case of terrorist attack. It's rather hard to do much to the first. And if it does break free, it does tons less damage in the first case (the tower+rope).
Correct Horse Battery Staple: 72 bits of entropy. Enter "Correct H" into google. When it generates the phrase, that's
maybe they need a more Intelligent Design??
Your post makes me incredibly glad I learned physics using only metric units.
Megainches??? Do real scientists seriously use such a measurment?
-- If you try to fail and succeed, which have you done? - Uli's moose
i'm not a rocket schientist or anything, but i would think placing a "ribbon" all the way through our sensitive and protective ozone layer would be a bad idea. we have put many small things into space, but nothing thats lng enough to go all the way through the atmospere. to me it seems kind of dangerous. anyopne else worry about this? i know i don't want my atmosphere to come colapsing down on me.
It sounds like a planetoid, to be honest. Sure is big enough to be one.
+++ATH0
We don't use rocket to get above the atmosphere. Planes can pretty much do that. Balloons can (and regularly do) do that. That's the easy part.
"Pretty much" only scores with horseshoes and hand grenades. To orbit, you have to get all the way out of the atmosphere, which neither planes nor ballons can do. Unless you know how to orbit in the atmosphere, you're going to need a rocket. Note that the X-15 has stubby little wings but that does not make it a plane. It produced enough thrust to lift itself straight up and it did not breath atmosphere--it was a rocket.
We use rockets to get velocity, because you need a ridiculous velocity in order to actually orbit the Earth at a low height.
Definitely true, but we also use rockets just to escape the atmosphere. See: SpaceShipOne.
You do not, however, need a ridiculous velocity in order to orbit at a very, very high height. At geosynchronous orbit, you need no velocity, because you've already got the speed from the Earth's rotation.
Actually no. At geosynchronous height you still need orbital speed. If you measure it as an angular velocity, you are correct that it is equal to your angular velocity on the ground. But if you measure it as a speed it is clearly far greater. The higher you go, the more speed you need for a stable orbit. That's why it takes bigger rockets to achieve higher orbits.
Build a man a fire, he's warm for one night. Set him on fire, and he's warm for the rest of his life.
Barawn, dude, I've been reading your exchanges with these Slashdot guys. I mean that miro and GooberToo and couple of anonymous guys, the ones with the poor reading comprehension skills and tenuous grasp of physics---but more than enough attitude to compensate.
I'd mod you up if I had mod points. Thanks for posting.
I wonder if growing a beanstalk from the ground to the cable will help. Hell there might be giants up there with golden-egg laying geese!
But really what happens when some jokester fires a missile at this mighty space string and cuts it down? It would sure be hard to protect.....
composite ribbon eventually stretching some 62,000 miles from earth to space
isnt space 50 - 65 miles up?
persons who travel above an altitude of 50.0 miles (80.5 km) are designated as astronauts
The Karman line, at 100 km (62 mi), is also frequently used as the boundary between atmosphere and space
Earth's atmosphere
so, if "space" is 62 miles up, and astronauts go to around 50 miles up, a good distance to take you "far" would be around... 200 - 300 miles? no more than 1000 would be needed.. so why do we need a 62,000 mile ribbon?
portfolio
how heavy would something like this be when its reaching out so far? wouldnt it throw out the earths rotation? (think fan with 1 blade)
portfolio
I never called the robotics "trivial", I called them simple in comparison to the CNT ribbon. I am a materials scientist working on Carbon Nanotubes (to also reply to your post below), and while growth isn't my concentration, I do know from the literature that the fastest growth acheived for CNTs is 10-100 microns/sec.
Now CNTs are only strong if they are continuous. In other words, if you spin a thread of them the tube to tube bonding would probably not be strong enough for the elevator. So to build the ribbon you have to grow continuous nanotubes to the length you want the ribbon. If we assume the upper limit on the nanotube growth rate I stated above, then it would take approximately half a million years to grow one mile of ribbon.
Since I'm not working directly on the ribbon I could be wrong about a few things, but the point is that there are several very tough technological obstacles to growing the ribbon. In contrast the climbers build on technology we already have, so that's why I said they are simple to build in comparison to the ribbon.
People?? Surely this thing will take a LONG time to get up into space? I guess the astronauts will have to get used to sitting in those giant suits.
I'm sure people smarter than me have shot this idea down before...but I won't let that discourage me. Why not have 1 long "belt-like ribbon" and just put a pulley in space. Have the motor on the ground move the cable along (earth motor)o========o(space pulley and weight). I'm too lazy to research why this is a terrible and physically impossible idea and I'm sure it has something to do with torque and gravity/friction/cable isn't uniform width all the way etc... Just curious as to why it is too ludacris for discussion here.
Did NASA consider their satellites in low earth orbit crashing into the tower ?
The question seems to be not whether it's possible, rather do we want a navigation hazard like this cleaning up valuable and usefull hardware ?
> The platform, a proprietary system that the company has ....
> named "HALE" (High Altitude Long Endurance)
"Open the elevator door, HAL-E."
"I'm sorry, Frank, I can't do that."
The idea of a long cable is not to get us out of the atmosphere, but to get us far away from the pull of Earth's gravity. If you climbed all the way to the end of the cable and let go, given you had escape velocity, you would get past anywhere. Uhh, from what I understand, there is this huge object at the center of our solar system who's gravity keeps a bunch of planets and comets circling it. You DO need a certain escape velocity to get out of the solar system.
There should be a "-1:Groupthink"
Hey what's with the stick up your ass? I never said it was a bad idea. In fact, although obviously I'm not as much of a fanboy as you are, from what I've heard about the idea it sounds like a really good one and I'm glad there's people out there that are willing to take the risks and spend the money to try it.
- It's not the Macs I hate. It's Digg users. -
Oh My Fucking Gods Are You People Complete Morons Or What?
I rate 95% of these posts from just plain uneducated to "lay off the crack man"
I am. Lower your shields and power down your weapons, they are useless. Your biological and technological distinctivenes
The location is picked as it is on the equator - so it takes less energy to get things into orbit. As nice as it might be to have it located in SF it would mean it costing more.
This "space elevator" thing can't be for real.
The safety issues involved in a thousand-mile ribbon falling to Earth are totally intractable.
The dynamics of this thing in weather will be impossible to prevent.
The reaction of it to pertubations in the Earth's motion will be impossible to compensate. (Oh yes, kids, the Earth does not turn like a perfect sphere in your imagination; it sloshes side-to-side, and its period is not close enough to a constant for this to be feasible.)
The idea that these people have tested a device that can climb a wire being any sort of proof of any concept worthy of funding the attempted launch of the real thing is laughable. I can point to any window-washing rig as an example of that sort of technology. They've done nothing significantly new.
Someone is taking the money-men to the cleaners on this boondoggle.
if instead of nanotubes, we used elastic, and instead of a 'counter-weight', we used the moon!
--AlexC
Just because I dont agree with climate change doesnt make me a troll
99.99999% of the atmosphere is below the highest X-15 plane flight on August 22, 1963 which reached an altitude of 354,300 ft or 108 km.
big difference to 62,000 km. however, I will concede that you did say "pretty much" do that. However, they cannot completely leave the atmosphere, as rockets can
simply by building our velocity high enough to escape velocity while in the atmosphere and letting inertia take us out.
Ignoring that whole "air resistance" and "speed of sound" thing.
if you get high enough in our atmosphere, there's less air to resist. The idea of escape velocity is if you reach 11.3km/s on the surface of the Earth you will keep going forever, provided that there is no retarding force (ie. ignoring Air Resistance). however, taking air resistance into account, you can STILL escape with a single push, you just need to go a lot faster (and have a very streamlined aircraft). This is of course simpler when you're higher upThat was the point I was trying to make.
I get velocity from the Earth all the time. It's called standing on the ground.
Funnily enough, this is NOT a geosynchronous orbit, which is what I was talking about.
That's what special about geosynchronous orbit. Orbital velocity is slow enough that I can use the Earth's rotation to supply it.
At Geosynchronous orbit you need to get about 36,000 km above the surface of the earth at a velocity of about 3 km/s. On the surface we revolve at about 0.46 km/s. I don't know what velocity you are getting from where, but it takes quite a lot of work to get a sattelite up to geosynchronous orbit and also accellerate it to the point of having it stay in orbit.
the ONLY special thing about a geosynchronous orbit is the geostationary orbit, whereby you can have an object in geosynchronous orbit above the equator, and it will stay in the same position relative to an observer on the Earth's surface.
It's not "negligible" - it's two thousand miles an hour (curiously, roughly 1 km/s). It's just neglible in the rotating frame of the Earth
ok, my apologies. I used the wrong word here. At this height, you have a lower escape velocity, you also have a much lower accelleration due to gravity. The escape velocity doesn't matter, in this case, because you don't really have much force pulling you back, you only need a small force to accellerate away from the Earth. This makes space travel very cheap from 62,000 miles
being vague is almost as cool as doing that other thing...
Darkman, please meet Sir Isaac Newton
The grass is only greener, if you don't take care of your own lawn.
Isn't the summit of K2 about 50km high? Wouldn't it be a lot easier to build a ramp up the side of a pre-existing geological feature? IIRC, atmospheric effects can still be severe at that altitude.
That's what special about geosynchronous orbit. Orbital velocity is slow enough that I can use the Earth's rotation to supply it.
it appears to me that you hold the belief that if you go straight up from the Earth, you'll keep rotating in line with the point you launched from on the surface.
This is wrong. Ever hear of the Coriolis effect? You must have heard of it. Basically if you throw a ball vertially up high enough, it will end up landing west of where you threw it from, because the Earth rotates underneath the ball. It doesn't "keep in step with the Earth" as you seem to think. Therefore we cannot simply launch a sattelite straight up and assume that the Earth's rotation will give it the velocity it needs in order to get into a geostationary object. It still needs to be accellerated quite a bit (460m/s to 3 km/s), because it's further out and needs to travel further.
being vague is almost as cool as doing that other thing...
And if it breaks up and falls to the Earth in a deathshower, it will be hail!
The 'Net is a waste of time, and that's exactly what's right about it. - William Gibson
interesting, it seems like it would be very fuel efficient cause of the low atmospheric air friction? unless the enormous size of the balloon makes the air friction large?
Just call on the people of the world to donate the chains off their old unused bicycles.
The construction of the chains would easily allow the joining of millions end to end. Of course, one bicycle chain isn't going to hold its own weight nevermind lift anything, so the solution is to use more than one. if 5000 chains started at the counterweight, and slowly joined until there were just 200 or so at earth level, then the many chains would support the few chains, and the transport would have plenty of room for a redundant fail-safe independent mechanism for climbing up the 200 chains simutaneously.
This is exciting, it would take a big part of the challenge of space exploration out of the way, and we could find ourselves building an SS Enterprise in our lifetimes.
Woah...
Rather than waste time I'll just point to what I said last time about this: security fears are overblown.
Any sufficiently advanced technology is indistinguishable from a rigged demo
--Andy Finkel (J. Klass?)
You haven't even come close to providing good reason to think it's less difficult. The problem is not the basic theoretical engineering. It's never going to happen. Cheers.
Often wrong but never in doubt.
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For those of you who are skeptical about the necessary nanotube unobtanium for the full space elevator becoming available any time soon, here's a link to a proposal that requires more feasible properties out of a tether, but still helps to lower launch costs a lot: Hypersonic Airplane Space Tether Orbital Launch (HASTOL) Study - Phase II.
Any sufficiently advanced technology is indistinguishable from a rigged demo
--Andy Finkel (J. Klass?)
wouldn't something like this slow down the planet? (I'm metaphorically ducking your tomatoes, so just assume I don't have the physics or math and explain why this isn't the case/ : ) )
Some people who haven't thought things through will argue that it can be shorter than that - but if you want to have the centre of mass in geostationary orbit you need to go out furthur as a counterweight.
The vast amount of mass you would need to move into orbit to make such a structure is only worth it if you planned to move incredible amounts of mass into orbit (or from orbit - it takes energy to slow down too). If you can get the materials from somewhere without as much gravity to deal with (a long haul from the asteroid belt or future lunar factories) it becomes less of a project.
Constructing a beanstalk now is like building a ten crane shipping container handling port to get a box out of a rowboat. I would be highly suspicious of commercial companies that even mention a timescale let alone a short one - I would go looking for the scam.
Does anyone have _real_ pictures of a space elevator in action? I see references to short runs done in real life, but never any good pictures.
In my experience, scientists do not- all they have to change is the units they think in.
Engineers, on the other hand, have to interface with the real world at some point, and that means using imperial units here in a lot of cases.
Maybe I'm not thinking it through fully, but if they started from the top down, might they be able to simply balance the forces on the cable and effectively have zero strain on it? That would reduce the need for super-strong cables, right?
I'm not vouching for the science behind the Sky Ramp, but it's similar to what you're proposing. The idea is to use a ramp and sled instead of a first stage. Beware: the website design is painful.
Q: What does the "B." in Benoit B. Mandelbrot stand for? A: Benoit B. Mandelbrot
And that's just the technical side of the problem. there are plenty of down to earth problems, too. If some equitorial country with 500 km^2 of uninhabited, unprotected land and a trillion USD to spend wanted to build this they would have even more problems. For the first 15 to ~20 km construction would be relatively easy. mainly standard construction pratices. However, most climbers above 8000 M use suplimental oxygen to prevent hypoxia. so not even 10% done and already the costs skyrocket. not to mention other expensive equipment like extreme low temperature clothing, etc. that goes along with this type of project.
just imagine the hazard pay for, who knows, 50,000 employees?
if they managed to keep going steadily with the temparature and air pressure droping the higher they go, and battling the weather every inch, before a stronger teather is created, that will be a sad day for nanotube researchers.
now, we dont have robots that can build skyscrapers single handedly (hell they can't even do it in groups). so don't say that we can just use robots, cause as i welcome our new robot overlords, they wiill not be here before, again, a better teather is created.
p.s. the foundation alone would be hell to engineer and would take years and years to complete
"how does that impact the pyramid idea?"
For starters, there just aren't enough LEGO bricks in existence to build this pyramid of yours. And even if there were, who gets to choose what colour it would be?
When we see the first F-350 series truck tractor pull with a carbon-fiber nanotube produced cable, your posting might be a valid one to make. But for now, theoretical materials or materials that are too expensive to conduct such trials on are not going to cut it.
"LiftPort successfully launched an observation and communication platform a full mile in the air and maintained it in a stationary position for more than six hours while robotic lifters climbed up and down a ribbon attached to the platform." Six hours of climbing up and down a ribbon? What? We are going to be ferrying multi-million dollar satellites into space using hair products? Did they lose the cable? I for one am going to need to see pictures.
Earth's gravity well technically goes to infinity but *escaping* isn't an infinity problem. Escape Velocity (11.2 km/s for Earth) is the convention... go outward faster than that and you're never returning. By definition, EV is the velocity needed to escape, so your statement that seems to deny the inevitable just seems like you spoke hastily.
Also, the universe is n-body, not 2-body. Once another planet or the sun dominates, you've escaped the earth forever. Yeah, I'm being semantic, but a precise and correct version of your first line probably shouldn't jump from an abstraction like an infinite well to stating that escape means being beyond that well. That's not how astrophysicists use the concept. Technically, Lagrange points also contradict your statement.
The mars rovers escaped Earth's well. Mars and the sun dominate. Earth's influence is orders of magnitude smaller than either of these two... smaller even than Deimos and Phobos. Saying they're in earth's well would get hoots and chuckles, wouldn't it? Saying that about something splatted into the sun would get the same reaction, I presume.
And the Pioneers/Voyagers are running outward so fast and so far away that the sun can't appreciably slow them down -- they're inevitably and completely gone. Yeah, it will be 100,000 years or more at more than 12km/s for something else to have more influence than the sun's... but the sun's been irrelevant since they did their gas-giant slingshot passes 20-30 years ago. And Earth's been irrelevant since a few months after launch.
Everything you say is correct. More accurately I should have said you can't escape Earth's gravitation influence, even at infinity. If we use the "escape Earth's gravity well" definition that you suggest (which I agree is the correct one) then the original poster I replied to is flat out wrong... at 62,000 miles up on a space elevator you have more than reached escape velocity from the Earth.
I think the second part of my post said basically what you did about going faster than escape velocity being the important thing.
I wouldn't live in the same hemisphere as this thing.
No sig today...
Carbon materials proposed for the cable are chemicaly active and electricly conductive or semi-conductive. I am trying to imagine the long term conditions for the cable. IANARS, but I believe I read that in near-Earth orbit there are free oxygen ions and solar wind particles floating around in the "vaccuum". Surfaces in long term orbit are corroded by contact with them. In addition, any conductor stretched through the varying magnetic fields will induce significant voltages and potential currents, especialy when exposed to an energetic solar flare.
A completely functional space elevator might degrade and fall apart in a short enough time to make it uneconomical due to short operational life.
That brings up another question -- How do you decommision one of these things? Explosively cut the ribbon near the base and let if fly off into space?
Any technology distinguishable from magic is insufficiently advanced. - Geek's corollary to Clarke's law
At this point that doesn't make sense. To build a space elevator you essentially need two things- a ribbon and a climber system. There are labs all over the world spending significant quantities of both government and private funding to develop longer, stronger, cheaper carbon nanotubes at higher production capacities. There is only one organization working on a climber system, and that's LiftPort.
Additionally, LiftPort is a modest operation. I wouldn't be surprised if the amount spent by just the US government on CNT research in a single day exceeded LiftPort's entire annual budget. If they were to work on CNTs their efforts would be an insignificant drop in the bucket. On the equally important (for a space elevator, anyway) climber system problem they're the only game in town, and can actually make a real difference.
-Cybrex
Boundless Expansion, Self-Transformation, Dynamic Optimism, Intelligent Technology, Spontaneous Order- BEST DO IT SO!
Instead of having the cable to come down to the sea level why don't we stop it in the stratosphere, at 40,000 feet? We could build a lightweight airport attached to the end of the cable that could also work as the earth-counterweight to the one in the space.
There would be a lot of benefits:
1) Since we would have only one (or few) elevator(s), having both of its ends free we could easily move the whole elevator all around the planet. Suppose one country needs to use it for three months they would lower a lot of transportation costs having the elevator more close to them.
2) We would avoid all of the cumulonembus and all the other bad stuff of the protosphere.
3) Most of the time we would already need some planes to transport the stuff to the elevator. Having our nearest cable-end already in the stratosphere would result in the savings of additional landings and take-off from the sea level.
4) No problem at all for 99% of the air traffic on earth (almost no plane could erroneously strike the cable)
5) We would save 40,000 feet of cable costs, both as for the material substances needed to build it and for the involved forces it must handle
6) It could be more easily moved to other planets once we need some elevators on Mars and the like (use old stuff on other planets and replace with new ones on earth)
Seems to me a great idea!
Bye
Use robots. Use robots that work in groups. The obstacles are safety and cost. If it's safer and cheaper to build a robot to perform a difficult task, that will be the way to go. For example, the mars rovers.
Take fusion as an example. Engineering is the art of solving difficult problems.
We're talking about 100,000 km long cable, that's enough to wrap around the earth about 10 times! How many people will be killed? What kind of environmental damage will be done?
A cannon is a fundamentally different idea then a rocket.
A "cannonball" projectile obtains its impulse by imparting it on its firer, in this case the earth, a rocket obtains its impuls by "firing" off its own mass.
In vacuum rocket is _way_ less efficient then the cannon, it has to carry its fuel, which it fires at great speed. (relative to the rocket)
In contrast the cannon fires its "thrust" at the whole earth, which barely moves in the rest frame, and hardly takes up any energy. Also the cannon doesnt need to carry fuel.
Ok im not saying a cannon is a good way into space, just that its energy efficient.
The shock of liftoff is a problem, also (as parent post said) air drag.
I think it may be possible to send out really small satelites with robust electronics with chemical cannons. Larger satelites may result in problems with the barrel. And I dont think people are cannonproof.
A railgun could stretch the acceleration, but it has to be incredably long to make it acceptable.
As ever, wikipedia has usefull links and information about space cannons
Ps could do the cannon-propulsion vs rocket propulsion in vacuum in math, so pretty sure of it.
If they were doing work with the carbon nanotubes, I'd be much more impressed.
From the LiftPort web site:
Our 15,000 sq. ft. Nanotube facility is gearing up to produce large quantities of mid-grade multi-walled carbon nanotubes for commercial and research use. We're entertaining partners interested in co-development, or leasing space in our facility to further development of CNT composites with glass, plastics, and certain metals.
Located in Millville, NJ, LiftPort Nanotechnology is ideally located for composite research. The region has a long history of composite and glass development with an excellent skilled labor pool. The local city and county governments are very motivated to help develop new technologies and have capital investment programs available.
... 61999 to go!
aoeu
(a) the projectile hits the atmosphere at extremely high speed when it leaves the tube when it comes out of the ground, or (b) you have to figure out how to build this vacuum tube very high up into the upper atmosphere.
Most of your arguements seem to be on the lines of 'we can build this thing that is 500m high with conventional technology, so to build something 500km high we just do the same thing, but do it a thousand times more.' Which, unfortunately, doesn't really work (or we would have a space elevator made out of a conventional cable long ago.)
Firstly, no one is going to raise an item to the top floor (all the way up to 62000 mi) by elevator. Space work can be done in less than 1000 mi elevation.
Secondly, the path to the 62000 will not be vertical!!
Now according to TFA the test setup was in place for 6 hours while a payload was just lifted to 1500 feet in an unspecified time. A mile is 5280 feet. There may have been several loads lifted up and down simultaneously (cue Beowulf commentary). It may be surmised that as an item is lifted higher and higher the effect of gravity and atmosphere will be low enough that it can be accelerated heavily to the final altitude.
Before the celebrations begin, recall how a governor on a spinning shaft can be used to slow down the shaft by extending weights farther away from the axis of rotation. This is not to say the space elevator will risk slowing the earth down, but rather any item moved farther and farther from the earth will have a greater and greater kinetic energy in the tangential direction if said item is maintained hovering over the same spot on the ground. If you just lift a feather to an altitude several miles from the ground, inside a vertical vacuum shaft, the feather will have an extremely high speed in a direction parallel to the ground.
If you are raising some load by space elevator but you don't want to spend energy to accelerate it tangentially, you have to allow the load to lag relative to the earth. The space elevator will spiral behind the platform at sea, perhaps going a good number of times around the world. This will result in a very very very long tether.
The geostationary point applies to a centre of mass, does it not? But what happens when a load is being raised? The centre of mass will be lowered, and to prevent the space elevator from collapsing, the counterweight in space may have to be initially raised in altitude, which implies the tether may be much higher than 62000 mi. As loads move up and down, the centre of mass will have to be maintained by moving the counterweight. If the tether spirals in closer and closer loops at higher and higher altitudes, the counterweight will have to move very fast just to keep the centre of mass at 62000 mi. Very fast means high energy requirements, which means massive motors. There will have to be some energy storage because the spiral will be partially in night shadow.
Know your pads. One time pad: good for cryptography. Two timing pad: where to take your mistress.
A pyramid - I actually like the concept because it can be made practical. There's no need to make it solid because that would make a big-time gravitational anomaly. There's no need to even have solid sides. Stability is achieved with a single point at the top, and if something is raised high enough, it's weight is low enough that you can just shove it away into orbit.
In order to counterbalance, it is recommended that the pyramid be built as six pyramids, with a square around the earth within each of the orthogonal planes. Thus, there are two pyramid peaks on the +/- x-axis, two peaks on the +/- y-axis, and two peaks on the +/- z-axis. Loads can be moved along or even within the sides of the squares.
Know your pads. One time pad: good for cryptography. Two timing pad: where to take your mistress.
Ever wonder why the worlds' pyramids are in equatorial regions?
You know, when I had my tires balanced, the weights had to be placed very carefully. We ought to be thankful that monkeys crawled out of the trees and prevented mass extinctions by stabilizing the spin of the earth. Break out the typewriters. We've never believed in monkey genius, but isn't it time we mined the gold in that data?
Know your pads. One time pad: good for cryptography. Two timing pad: where to take your mistress.
it appears to me that you hold the belief that if you go straight up from the Earth, you'll keep rotating in line with the point you launched from on the surface.
:)
I will if I keep holding onto a giant pole. Which is what this is.
Maybe I'm missing something but how do they intend to get the cable/ribbon into space in the first place? Have it trailing out of a rocket that they shoot up and hopefully it will withstand the heat? Or are they launching it up in a coil and then lower it back down to Earth?
balloons do NOT get above "99.9%" of the atmposphere.
.1% atmosphere is REALLLLLLY high
:)
You know, would you please make sure you know what you're talking about first? Because maybe, just maybe, the person you're talking to has built something which went up on a balloon to over 99.9% of the atmosphere. Ever think about that?
And I have, for the record. Technically it was an LDB balloon, but the float altitudes are basically the same. It's just a question of whether or not the atmosphere was pressurized or not.
That site says 99%, but that's actually a little low (they're simplifying it). The height for an LDB flight is about 40 km. Atmospheric density there is about 1 to 2 x 10^-6 g/cm^3. Atmospheric density at ground level is 1.2E-3 g/cm^3.
Dividing, I get that the atmospheric density at float is - gasp one part in a thousand, or 99.9% of the atmosphere is below you.
Do you even have any idea how high up that is?
Yah. 40 km.
not the atmosphere was pressurized or not.
BALLOON was pressurized. Dangit.
Sure, the angular velocity of an object in geosync is the same as one on the ground, but that means nothing.
Except for the fact that it means you can grab onto something on the ground and use it to let you move faster.
The only reason a space elevator is cheap is because it steals momentum from the earth.
Because the angular velocity is low enough. We steal momentum from the Earth all the time for rocket launches - we launch in the direction of the Earth's rotation (which pushes the atmosphere back, which slows the Earth down).
It's just that at the Earth's surface, the angular velocity required for orbit is way, way higher than what you can take from rotation. At geosync, it's not.
The more you play with the Orbiter simulation of the space elevator, the more you realize how impossible it is. Like an asteroid is just going to park itself in exactly the right position for capture by the space elevator or something that percarius is going to survive wars.
"Pretty much" only scores with horseshoes and hand grenades
The Shuttle SRBs shut off at nearly the same altitude as balloons reach. Scientific balloons are up at 40-50 kilometers. At that point, you're above 99.9% of the atmosphere. If you really wanted to, you could get almost arbitrarily high - it's just a question of how large you'd like the balloon to be. Like I said. But you don't use balloons instead of the SRBs, because the SRBs supply humongoid amounts of velocity as well.
To orbit, you have to get all the way out of the atmosphere
To orbit, you need velocity. Whether or not there's atmosphere only tells you how long you're going to orbit for as your velocity bleeds away thanks to air resistance.
Heck, the Space Station is still in the atmosphere, and it's orbiting.
There are a whole host of ways to get things to high altitude, but none of them really work clearly better than rockets because you need velocity - that is, none, save the space elevator, which accelerates very, very very gently over a very, very long cable.
Orbiting tethers, for instance, could pick up a payload off of a balloon-launched payload. That'd get you to a high altitude, but in order to pick up the velocity required, the payload would experience a supremely ridiculous amount of stress when the tether picked it up.
Or you could launch a rocket off of a balloon-supported platform. But again, the stress would be insane because the amount of velocity you need to gain in such a short time is so high.
Or we could build a really, really tall tower. But unless we get out really, really far, that tower won't do a tiny bit of good, because the (angular) velocity you need is so freaking high that, again, the stress would be nuts. Or you'd use a rocket - but the fuel savings on the rocket wouldn't be that large.
The atmosphere is essentially gone by 50 km. It's down 3 orders of magnitude. At 100 km, it's down 6 orders of magnitude. At 150 km, it's down 9 orders of magnitude. But even building a gigantic tower out to 150 km wouldn't significantly help with launching a spacecraft. You'd still need a rocket.
Actually no. At geosynchronous height you still need orbital speed.
Yah, yah, it should've said "angular" velocity there, not velocity. I do, however, commend you on saying that in one paragraph rather than 5 as the other poster did.
That and femto light-years for trips to the corner store.
Get rid of everything Micro and Soft: Buy Viagra and/or Linux
Sorry public terminal so I am not logging in. Anyway if you create a wind turbine on the ribbon tower etc you have now added a force perpendicular to the ribbon equal to the mechanical energy generated by the turbines + the losses due to efficiency. NOT GOOD. Most materials are not nearly as strong in 1 direction as they are the other. The best example that you probably have seen would be a steal cable. It takes much load to make the cable longer, but no real effort to bend the cable (yes I know that I would need to take into account the tortional radius for the exact ratio but that is not important for the basic example.)
If you want to create electricity then you simply use a very long conductor. Swinging a 62 mile long rod through a varying magnetic field (the earth) creates an induced voltage. But given the fact that you don't want to provide enough potential for the carbon chains to turn into ash that also may be a bad idea.
The robot started 1499 feet from the mile mark :)
K2 is more like 8km high.
i'm not down on robots, but your idea, extreme environment construction robots that work together, is 50 years away at least, especially for reasonable priced, mass producable versions. something like that would have inumerable value, but is a project as difficult as the space elavator, which is the goal at hand.
if you are trying to say that anything is posible with enough inginuity, i'd agree. however, there are pratical constraints to that statement. you don't want to add to the complexity of an already difficult problem.
a space elavator? sure, it will be worked out it good time. i can wait for the nanotube cables to be perfected. but building a pyramid so that you can use existing tether materials in an attempt to be the first with an elevator is assinine. it's assinine because it would fail to accomplish that goal. it would take them so long to engineer and construct the damn thing that by the time they got the first 5 % done the nanotube cable would be worked out.
i can go on and on about problems you would encounter that have nothing to do with engineering, too. red tape, supply lines, environmental impact studies, etc.
also, when i said 'the foundation' i ment the physical foundation like on a house, not some body of knowledge that would make it all worth while. regardless a structure this massive would deform the techtonic plate it sits upon. everest already does, and is nowhere near the size of this 'space pyramid'.
but hey if you wanna build it don't let my logic stop you
ok, now I'm confused. I thought we were talking about geosyncronous orbits, not the space elevator. There's no giant pole for the space elevator.
Anyway, as far as I understood, it was a giant Ribbon, not a giant pole. I am quite sure a pole 62,000 miles long would be quite bendy
being vague is almost as cool as doing that other thing...
that's "there's no giant pole for geosynchronous orbits"
being vague is almost as cool as doing that other thing...
ok, now I'm confused. I thought we were talking about geosyncronous orbits, not the space elevator.
I was talking about the space elevator. The original point was why the space elevator needed to go to GEO. It needs to go to GEO (and beyond) because GEO is where your angular velocity is equal to that on the ground. So you don't need any propulsion.
There's no giant pole for the space elevator.
Er? The space elevator is a giant pole. Ribbon, pole, same thing. It's under a ridiculous amount of tension so it's not like it won't be very, very near vertical.