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Space Elevator Challenge
MattSparkes writes "For the second year in a row, no team has won the $200,000 prize in the Space Elevator Challenge at the Wirefly X Prize Cup. Three teams were disqualified before the contest even started. Another competition at the event has been held up by confusion. Incredibly, it seems the organisers of the competition are not sure whether the ribbon used was 50 or 60 metres long, and whether any team completed the climb fast enough to win."
Well it seems that this will be won next year :)
More and more I see that this sort of prize is excellent way to foster development of new technologies. This should be applied to other technical challenges we face...
Nothing in the world is more dangerous than sincere ignorance and conscientious stupidity.
The structure of the elevator isn't the only technology that has to be developed. We also have to make a climber that can go up a thin strand of material and hold wait, as well as a way to power it. Not all of these require carbon nanotube robes to build.
Does a line appended to your comment give your post meaning in and of itself, or only in relation to those without?
I think that the material to make the ribbon can't actually be produced yet, and a 50-60 metre long section is about all that can be used. However, for the purposes of a test like this, it will suffice. The competition is more to do with getting the elevator technology advancing than actually putting together a working device.
Matthew Sparkes
RTFA. You do not need to climb to orbit to win the prize. "a test of over 20 teams to use light to power a vehicle along a tether, this year up about 50 meters..."
SHE does throw dice.
The competition was for building a vehicle to climb the ribbon, not making the ribbon itself.
There is a seperate competition for designing/making the actual ribbon.
Ref: http://www.elevator2010.org/site/competition.html
=Smidge=
is already responsible for a major advancement: the first private space ship able to relaunch in two weeks (SpaceShipOne).
The prize is definately motivation, and the X-Prize foundation has a few contests going:
-The Ansari X-Prize (Get 3 people to 100km twice in two weeks) - WON
-The Archon X-Prize (Sequence 100 people in 10 days with $10,000 cost per person) - OPEN
-The Automotive X-Prize (Currently being developed. Create super-efficent cars or alternative energy) - FUTURE
Those are the three the X-Prize Foundation has created. An interesting fact from the X-Prize website: "Ten times the amount of the prize purse was spent by the competitors trying to win the prize."
"Dictator Flakes. They WILL be delicious."
To be fair, it doesn't matter much if they have funding to make the tether, since the tech to do this isn't even possible at the moment. A lot of people get stuck on carbon nanotubes and think that a space elevator is coming tomorrow, but when you look at current research we aren't really up to making a long fiber out of nanotubes (and when/if we get there, there are heat properties that I always wonder about in a space elevator, for instance a photo flash is enough heat to ignite loose nanotubes). The contest is really meant to develop that sort of tech.
That being said, yeah small teams would have a hard time with it. though they didn't say who was funding the disqualified teams, they did say the team that tested was part of an aerospace company.
Infosec: "We don't really know what you're doing, but we're certain it's bad. Disqualified!"
Development: "We're not sure how long the cable is supposed to be, so we'll hardcode it in the top of the code. If we're wrong, its out of scope and we won't fix it."
Engineering: "We don't know how fast it is supposed to climb, so we'll pick a value. If we're wrong, it was Marketing's failure to gather the right requirements.""
Audit: "All your project are belong to us".
Milton: "I could just burn down the building..."
Geez, who is running this thing, the PHB?
I want to delete my account but Slashdot doesn't allow it.
If you attach a weight to a rope and spin it around your head the inertia of the weight will keep the rope tight. Because the Earth rotates, a large mass a long way out in space should be able to keep a line tight. The bottom end would be attached to the Earth, preferabley close to the equator. A station close to Geosynchronous orbit will be in microgravity. The weight at the end of the cable will experience rotational pseudo gravity. Objects dropped from this point will enter solar orbit.
http://michaelsmith.id.au
If I'm going up in to space on a giant elevator, I want it to be nailed on to something a bit more substantial sounding that a 'ribbon'. Heck, all the ones I used to read about in 1950's sci-fi books were basically normal elevators, steel girders, nice big box with windows, sliding doors etc., just a hundred thousand feet high. THAT's what I'd feel safe in.
I want a list of atrocities done in your name - Recoil
In theory it works well. In practise I think it's more of a pipe dream and I believe NASA knows it. We have one football field sized structure that's taken the better part of a decade to build. We've never constructed something anywhere near the magnitude for the size this thing is going to be and as far as I know there isn't a good engineering plan on how this thing is supposed to be put up. However they're desperate for whatever good will and publicity that they can scramble to get and this competition even with all it's strings attached is a pretty good and inexpensive way to generate some.
And not ONE picture or movie about it? How come?
According to the rules, the circumference of the loop must measure at least 2 metres. ...the Snowstar team from Canada's University of British Columbia, for example, was shy of this by less than half a millimetre.
The diameter of their spool was 0.25% smaller than required, which was probably the result of warping from moving the spool around so it could be weighed, etc, before the competition. So they were disqualified and didn't get to formally compete.
The height of the robot climb is what got me. It's a timed event, and the height they had to climb might have been 10 meters further than the benchmark. Now that's a complete joke.
Dan East
Better known as 318230.
You know how people sometimes use the metric of "If you stacked all the X in the world (graham crackers, AOL CD's, empty pantyhose containers) end to end, it would reach the moon and back!" My tentative plan is to find those items and to dedicate them to that exact purpose. Mole of Twinkies stacked end to end, here I come!
I can't imagine you don't know how a space elevator works AND don't know how to find out ... in any case, I'll presume you aren't trolling.
See http://en.wikipedia.org/wiki/Space_Elevator, or for that matter Arthur Clarke's "The Fountains of Paradise".
The clue is that an elevator is attached to a *GEOSYNCHRONOUS* satellite. That is, it will stay at the same place above the Earth's equator. Granted, there would probably be some amount of drift, but that can probably be solved by applying steering thrusters to the whole contraption.
So you have to go to the place where the elevator is; but once you're there you can just use it as any ol' elevator.
"Good news, everyone!"
Ding. The footprint for a truly sturdy space elevator would probably be around the size in square mileage of Delaware, if not greater.
You start at geosynchronous orbit over the equator. You spin your cable both down towards earth and up into space at the same time, which balances the cable.
Actually, they did, but in classic NASA fashion, they couldn't remember if they did it in metric or not.
Can anyone enlighten me how that thing supposed to work?
See Wikipedia.
We fasten one end on ground and second end is fastened... where???
To an orbiting counterweight.
And what about Earth rotation?
Earth's rotation is what makes it work. Otherwise:
I still think that normal elevator - a-la tower - is much saner idea and can be achieved easier
Yeah, nobody ever thought of that idea. They're pursuing orbital tethers because they're all insane masochists.
A tower would be much more massive and would have to support its full weight. Tethering to an orbiting counterweight allows centrifugal effects to lighten the total load, since the Earth is rotating. You couldn't build one high enough to reach geosynchronous orbit, and thus whatever you brought to the top wouldn't be in a nice circular orbit when it got there; it would still need something like rocket thrust. With a tether, as soon as you get up to geosynchronous, you're automatically in a circular orbit. See the "compressive structure" entry on Wikipedia.
For those who don't have a good understanding of Space Elevators other than some Sci-Fi you may have read that was written 50 years ago: A space elevator consists of 5 primary components: 1. Base Station 2. Ribbon 3. Climber 4. Counterweight 5. Power system This contest is an attempt to trigger innovation in the area of power and climber, not in the ribbon, station or counter-weight. The ribbon would need to be a carbon nanotube-based composite that is a matter of microns thick and very wide. The width of the ribbon would change based on whether it is in Earth's atmosphere (very thin - less affected by wind and less of a danger) or outer space (very thick, to be able to recover from damage from debris). The ribbon would stretch from a base station to approximately 125,000 km to geosynchronous earth orbit, at which point there will be a counterweight - initially the spacecraft used to deploy the ribbon and eventually an orbital station. The climber drives up the ribbon with an electric engine, and will need to be powered wirelessly. Currently the predominate thinking is to use a laser to hit solar-panels on the climber that are tuned for the particular wavelength of light that the laser is emitting. Initial Space Elevators, built in about 10 years for about $10 B, will be able to carry 20 tons of material at a cost of ~$300/kg (contrast that with the next-gen shuttle - $100 Billion, with a capacity of 40 tons @ ~$10,000/kg), with subsequent elevators able to carry up to 200 tons at a cost of $100/kg.
More specifically, at the equator it would be geostationary orbit.
Bigger Gyro?
A straight tower couldn't be built. The tensile pressures on the building would be insane. Heck, we can't even make the ribbon yet, and it's an easier task (though still not exactly easy) than trying to build full-on girders.
The problem is the music. We can all stand elevator music for a few seconds, maybe a minute or two. But could you imagine dealing with it for hours? We'd all go stark raving mad!
Small potatoes make the steak look bigger.
I think that the reason that we have no space elevatos is the same reason that we haven't been to the moon in 30+ years. Nobody has made it a priority. Kenedy made it a priority to get to the moon, and NASA got the necessary funding. Lately presidents haven't been willing to spend so much money on space exploration, but would rather spend money on things like national defence.
Anthropic principle: We see the universe the way it is because if it were different we would not be here to see it.
Just curious why it is taking so long to measure the the ribbon to see if it was 60 meters or 50? Is there a specific process to it?
Can I bum a sig?
Precisely my question. So you are saying that tether might be possible to be made so light and strong - but no way simple tower construct would achieve the same???
If you can make tether that strong and light, you can use N of them to make tower stand. Materials for such tower also can be very very light and very very hard. But probably to not such greater extent tether has to be strong.
What makes super-super-strong tether in your mind possible and super-hard and super-light tower impossible?
But how heavy it would have to have? I shiver to even think that thing might alter (or even de-orbit) Earth. The wikipedia page doesn't answer that question.
It kind'a reminds me of other problem, since again we forget about balance.
All hope abandon ye who enter here.
bubblegum crisis 2040 has a neat space elevator
gunnm (battle angel, manga specifically) as well, this one uses the premise of geosynchronous orbit
Not too sure if you are joking, but I'll bite:
We probably could build a tower from known materials (eg stone which is really, really, hard to crush, hence cathedrals etc). However, a tower is not stable. It would fall over at that height, even with our current best engineering efforts. Unless you made it very wide. Very, very wide, as it needs to be at least 50 miles (70 would be better) high to be useful. Our current tallest buildings are less than 600m high (that's less than 1% of 50 miles).
The other end of the ribbon is fastened to an counterweight asteroid a long, long way out, in geo-synchronous orbit. This means that it would be a stable structure requiring no special real-time balancing act. The (forst) problem is that we don't have a material with sufficient tensile strength.
We are currently believed to be more likely to solve the problems in (2) than (1). We may be wrong!
Justin.
You're only jealous cos the little penguins are talking to me.
They might be able to decrease the reaction time, which would make the reactions smoother. Also, they can change the 4 little side engines from either being on or off, to being able to throttle different amounts.
Ewige Blumenkraft.
Well, according to wikipedia, the size of Delaware is 6 square Kilometers. If it gave us an easy to way get things into orbit, I think that it would be worth giving up such a small piece of land.
Anthropic principle: We see the universe the way it is because if it were different we would not be here to see it.
Why this fixation on electric motors for the climber? The travel takes way too long this way. Use rocket engines, I say. Fast, solid, space-proven technology. Plus, you might be able to avoid the tether construction entirely!
Nuffsaid
________
Don't know about his cat, but Schroedinger is definitely dead.
Why not make the first challenge a 100 metre elevator. Which is still pretty tall.
There would have to be some weight restrictions. Build a tower that tall and see who can
climb up.
The station is in geostationary orbit. The counterweight is beyond geostationary, exerting considerable tension on the cable.
Socialism: a lie told by totalitarians and believed by fools.
But how heavy it would have to have? I shiver to even think that thing might alter (or even de-orbit) Earth. The wikipedia page doesn't answer that question.
Do a couple of calculations. The ribbon is a fraction of mm thick and from some mm to maybe one meter wide, and 40,000 km long. Its mass is very small, some thousands of tonnes probably. That's insignificant with respect to Earth's mass.
A tower, on another hand, would be *much* more massive, not to mention impossible to build with any known, or foreseeable, material.
O Rly?
Area Ranked 49th
- Total 2,491 sq mi
(6,452 km)
- Width 30 miles (48 km)
- Length 100 miles (161 km)
- % water 21.5
- Latitude 3827'N to 3950'N
- Longitude 752'W to 7547'W
( source: http://en.wikipedia.org/wiki/Delaware )
Slashdot still doesnâ(TM)t support Unicode after it was added to the HTML standard in 1997.
...send the next payload up "out of phase" with the oscillation caused by the first one? (its good that space elevators can swing back'n'forth btw... thats how the one on Mars is gonna avoid getting hit by Phobos).
IOW, the tether would manage to: (1) be very light, (2) be strong enough to sustain centrifugal energy of counter weight, (3) be even more stronger to carry useful load.
Just how this more feasible that ribbon is a fraction of mm thick and from some mm to maybe one meter wide would manage that?
Your post suggest that material for tether/ribbon is already known. So why we held that competition then? ;-)
The materials are not known. And it is kind of gamble to know which material would be invented first: one to make the tether or one to make a tower.
Tower doesn't have to be all that tall. It must be high enough to fraction Earth gravity force by e.g. ten - requiring ten times less of fuel to launch elevated rocket. That would already be achievement. With "space elevator" - no such gradual progress seems to be possible.
All hope abandon ye who enter here.
Ok I am not a physicist or civil engineer or anything... but it seems to me that you can't make a building out of rope ;) :)
Some materials are engineered for compression, such as the hollow bricks you so often see, and other materials are engineered for tension... a rope can't hold itself upright, it will fall down and fold, and if you try stretching a brick you will simply break a piece off of its edge.
Go play some Pontifex or Armadillo Run... it makes this sort of physics a tad more intuitive
Compared to this project, the moonshot doesn't even approach cakewalk status. You have absolutly no comprehension of the sheer physical size that this would entail.
sorry, i meant to type 6000, either way, it's a small piece of land if the space elevator works as well as it should.
Anthropic principle: We see the universe the way it is because if it were different we would not be here to see it.
So you are saying that tether might be possible to be made so light and strong - but no way simple tower construct would achieve the same??
Yes. The tether is kept under tension, rather than compression. Different material properties in question. As I said, a tether with an orbiting counterweight has to support less of its own weight than a compressional tower does, due to the centrifugal force.
While a material with appropriate tensional properties for a tether is hard to achieve, a material with appropriate compressional properties for a tower is even harder to achieve.
But how heavy it would have to have?
That depends on the design. Some designs have counterweights on the order of 100-1000 tons.
I shiver to even think that thing might alter (or even de-orbit) Earth.
It's in high orbit (above geosynchronous). It can't just "deorbit" and fall on us; there isn't any atmospheric friction to speak of. It would require enormous energy to alter its orbit to intersect the Earth. You might as well worry about the Moon falling on us.
It kind'a reminds me of other problem, since again we forget about balance.
What the hell are you talking about?
In theory, that's true. In practice, however, science fiction has been a pretty good predictor of technology to come. It's not 100% (yet), but quite often, the 'super high tech' stuff of sci-fi is developed a few hundred years *before* the sci-fi predicted it would be. As for most of the rest? Well, we're running a bit late on actually *using* flying cars, but the technology for them exists.
Tower doesn't have to be all that tall. It must be high enough to fraction Earth gravity force by e.g. ten - requiring ten times less of fuel to launch elevated rocket.
Reducing the force of Earth's gravity by 10 doesn't equate to 10x less fuel. The fuel required is a function of the change in velocity needed; it's more related to reducing energy than reducing force (1/r vs. 1/r^2). See the rocket equation.
Anyway, the altitude required to reduce the force of Earth's gravity by 10 would be almost 14,000 km above the Earth. And you still wouldn't have the right velocity for orbital insertion.
With "space elevator" - no such gradual progress seems to be possible.
Orbital tethers don't have to be geosynchronous. See tether propulsion. Besides, if you crunch the numbers, you will find that a compression tower has to be quite high before any substantial benefit in fuel reduction is achieved.
On the very remote chance that you aren't a troll, the moon is about 10 times further away than geostationary orbit.
This isn't even the biggest problem with your proposal.
Keep It Simple Stupid
;)
Just build a space ladder.. and then you could lose some weight on the way up to space.
If you can make tether that strong and light, you can use N of them to make tower stand. Materials for such tower also can be very very light and very very hard. But probably to not such greater extent tether has to be strong.
What makes super-super-strong tether in your mind possible and super-hard and super-light tower impossible?
Well, for one thing, tensile strength and compressive strength aren't the same thing. A substance which would withstand the pulling force of a fixed space elevator (from earth's surface through GSO to a counterweight) would not necessarily be able to withstand the compressive force of supporting its own weight.
Then there's the balance issue. If you build a tether with its center of mass at GSO, it's in free orbit around the planet. This means it has zero chance of falling over, whereas a shorter tower's center of mass would need to always be over its surface footprint. The higher you make the tower, obviously, the harder this is to maintain.
If you can make tether that strong and light, you can use N of them to make tower stand. Materials for such tower also can be very very light and very very hard. But probably to not such greater extent tether has to be strong.
This is simply untrue. If I'm standing on top of a building and lower a rope to the ground, someone can climb it. This doesn't mean you can build a tower of that height out of the same material (a rope). (In this analogy, the top of the building is the counterweight on the end of the tether, which holds it taut)
But how heavy it would have to have? I shiver to even think that thing might alter (or even de-orbit) Earth. The wikipedia page doesn't answer that question.
It doesn't answer this question for the same reason it doesn't answer the question of whether the Klingons will think that the tether is a threat to them, and therefore attack the human race: it's a complete non-issue. For one thing, the earth gets heavier every day, as crap from space falls into it (from dust all the way up to visible meteors), probably more in a year than the mass of the asteroid counterweight. I'm not worried about de-orbiting the planet anytime soon, are you?
If you're really worried about it, let's make the counterweight out of material taken from the planet, thereby not changing the planet's mass at all, and therefore not affecting its orbit around the sun.
I don't think you grasp how much mass and velocity the planet has.
Reality has a conservative bias: it conserves mass, energy, momentum...
I'm not certain what the original poster meant by this sentence, but I took it to mean that the space elevator and counterweight would affect earth's orbit around the sun. I doubt that the mass would be enough to make a significant difference, but it would certainly change earth's center of gravity to some degree.
Along this same line of thought, this could have an effect on tidal patterns as well. (The part of earth near the elevator might experience a "permanent high tide".)
Those are loose nanotubes. I have another experiment for you: Get a 3" square of some copper screen, made with a fairly small wire. Try to melt the center of it with a lighter; experience defeat. Now pull one wire out of the mesh, and try to melt it with a lighter. You will succeed. In that moment, the student will be enlightened.
"You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
OK - let's shoot for reducing acceleration from gravity from 9.8N to .98N, as you suggest.
Gravity falls off according to the inverse-square law. So, to achieve 1/10 the force of gravity, you need to get sqrt(10) times as far away from the center of gravity of the planet. So we have to get just over 3.1 times as far from the center of gravity as we currently are.
So, how far from the surface is that? Let's assume that the planet is a perfect sphere of uniform density, which will make the center of gravity (conveniently) co-located with the center of the planet. According to Google, the radius of the earth is 6,378.1 km, but we're using two sig figs for the multiplication, so we'll call it 6,300 km. Obviously, three times that is 19,000 km. Subtract the 6,300 km we're already at, and we're at 12,000 km.
Now, explaing to me again how it's so much more feasible to build a tower 12,000 km tall than it is to build the tether with a counterweight?
Reality has a conservative bias: it conserves mass, energy, momentum...
The presence of a 1000-ton mass beyond geosynchronous orbit will have an utterly, utterly negligible effect on the Earth's center of gravity or on tidal forces.
Take tidal forces, for instance. The distance geosynch orbit is about 40,000 km (I'm rounding up to 1 sig fig); the radius of the Moon's orbit is about 400,000 km. Since the counterweight is 10x closer to the Earth than to the Moon, that increases its tidal strength by the cube root of 10, or about a factor of 2. However, that is offset by a 10^20 reduction in mass. So the tidal forces due to the counterweight would be almost a billion trillion times weaker than those of the Moon.
The counterweight used in many space elevator designs is not that much more massive than the International Space Station. That certainly doesn't produce significant gravitational effects, despite being in low Earth orbit instead of geosynch. Hell, even a typical-size asteroid in low Earth orbit wouldn't produce significant gravitational effects at the Earth's surface.
No, it's the cube of 10 i.e. 1000. This is still, of course, completely insignificant.
a,e,i,o,u and sometimes w and y (at be if of up cwm by)
obviously the "easiest" way would be to put a cable factory into geosync orbit then and make the cables, then there are two different ways to do it;
1. make two cables one going down, and one going up to counter-ballance. after a while the downward bound cable touches the ground and gets tied off you keep making the downward a bit longer to stand-off the countermass from the geosync point. Then if possible You then add mass to counter-ballance and reel in the counter-mass cable as you go. once the counter-ballance cable is all reeled in, you detach it and fly it over to elevator station 2.
2. you take a reeled cable manufactured is space and carefully unreel it to the ground while keeping the center of gravity at geosyncronus orbit.
This is conceptually simple and elegent, but the engineering will be mind-boglingly difficult, I doubt it'll ever happen because we've never have a material with enough strength to mass ratio. Imagine how much static electricity a cable that long would gather, it would be the world's tallest lightning rod.
Apocalypse Cancelled, Sorry, No Ticket Refunds
Today's fun fact: a mole of Twinkies stacked end to end, assuming they're about three inches long (I haven't one around to measure), would stretch from here to Andromeda and about 90% of the way back.
Sorry. I got the video from a news site. They didn't carry the text of the page
http://www.dieblinkenlights.com
Nice to know. I'll try to find a video of that flight.
http://www.dieblinkenlights.com
So you can't play if you're off by a millimetre, but if they're off by 10m or so, that's ok. :-P
A big base also means a immobile base. The most considered plan for a space elevator has it anchored to a platform at sea. That allows it to move out of the way of storms and other localized issues.
That brings up an intersting idea though - your tower could float at sea. Every 100 meters of tower decreases the material constraints on the ribbon - though not by that much.
Personally I think a space elevator on earth is a bad idea. The material constraints are too close to the scientific limit of carbon nanotubes. We should build an orbital ferry with a tether that drops down to the edge of the atmosphere to grab more conventionally lifted payloads. This is sometimes called a sky hook.
The orbital ferry would have it's orbit recharged by also catching carefully timed high velocity dead mass. The recharging mass would come from earth (or moon) based accelerators. In a charged state the ferry has a highly elliptical orbit that still brings it in, very close to the earth. The discharged state is a simple LEO orbit.
You also have to handle the oscilation modes of the cable as a plucked string.
Seems to me you can turn this to your advantage:
Initially the climber plus payload pulls the counterweight back - but then it swings forward, converting a backward momentum delta to a forward one, which you can then use to accellerate the payload further with more climbing. When you get to a decent release point you can also wait until you've got extra forward momentum to help circularize your orbit or improve your launch, and let go then.
You end up with the whole thing in some combination of string vibration and pendulum oscilation. But you can damp much of that out on the climber's way back down - unless you want to deliberately leave some of that energy and momentum in the elevator's motion for use by the next payload.
The point is that by modulating the climber's travel rates you can move energy and momentum among the vibration modes, payload motion, and Earth's rotation, ending up up dumping it into the payload, where it's useful, rather than accumulating it in the cable and counterweight until you pull the counterweight out of orbit.
Devil's in the details, of course. You'll need a bunch of computation and to tweak it with feedback measurements from payload to payload. (If nothing else, wind loading will pump up the vibrational modes.)
You might also put "dampers" on the cable. In particular, by letting part of a climber's mass move sideways with the cable and part lag behind you can collect vibrational energy at the climber, damping it out of the cable's motion, and using it to generate power for more climbing. (Or avoid the extra gear on the climber by doing it at the ground station - letting the attachment move along a track with a generator/motor/actuator attached, to damp out the reflection by recovering the power.)
It might be interesting to analyze how much energy you could send up the cable to the climber by shaking it. (Probably not enough. But worth a look - especially if the cable is not prone to fatigue.)
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
In terms of energy required, it takes the same amount of energy to climb at 1 m/s as it does at 1km /s. The difference is in air resistance that is very high at high speed (function of v ^2).
The only benefit of the thether system is that it allows slow speed climbing. For some reason, we don't value trains that go 1 m/s, and if they can't have climbing bots go up and down on the same thether, which would indeed seem like a big complication, and there's no room in space to store a bunch of robots so you can send them all back down at the same time, then you can only bring a small payload up to space every 10 days. The reason trains don't go 1 m/s even if it saves fuel is that efficient track utilization is important too.
It might take decades in order to get sufficient payload totals up there to justify (as in break even on) the energy savings of building the thethers, and its not clear that these cables will last decades.
I was one of the team leaders for one of the elevator games teams. The article linked here gives some sense of the incompetence of the competition organizers, but the truth of the matter was far worse. The climber challenge was fraught with late/nonexistent equipment, no parity in the rules between the teams, vague rules and inaccuracies along every step of the way. The tether strength challenge was a joke, with professional organizers funded by NASA failing to properly carry out a test that any science/engineering student could do in first year.
To give an analogy, dozens of teams put thousands of dollars and hours into building race cars, only to show up at the venue and find that instead of a formula one circuit there was a dirt track through a cornfield. Our team spent thousands of hours on our entry and so did all of the other participants. It's too bad the organizers couldn't have repaid this dedication and passion with a small amount of their own effort.
Why was that modded "flamebait"?? It's the first realistic comment in the entirel thread!
We're all born with nothing.
If you die in debt, you're ahead.
The station is in geostationary orbit. The counterweight is beyond geostationary, exerting considerable tension on the cable.
If it is beyond geosync, then its orbital period is larger than one day. The "tension" it will exert on the station is thus not radial away from the earth but towards slowing the station down. Slowed down, the station will fall closer to the earth.
The whole thing will simply wind up around the planet.
And at all of /. there's nobody capable of doing the imple math to recognize that.
Pitiful, really.
We're all born with nothing.
If you die in debt, you're ahead.
That comment was modded flamebait because it asserted that Space Elevators will never be a practical proposition, and further suggested that many people seem to assume that technologies seen in science fiction are merely a matter of time. These ideas are antithetical to a certain subset of Slashdotters, the ones who post to stories about space elevators, Mars colonisation, interstellar spaceships and the like in particular. They really don't like the idea of hard limits imposed by physics. It seems to upset their notions of Manifest Destiny...
Everything I needed to know about life, I learnt from Blake's Seven
The Fountains of Paradise by Arthur C Clarke is well worth reading. He describes in detail a space elevator project in a future (and slightly modified) Sri Lanka.
http://michaelsmith.id.au
It is not in orbit. It is tethered.
http://michaelsmith.id.au
It's an elevator, for cripe's sake. We've had them since the 3rd century BC. They've been reasonably safe for over 100 years now.
No new technology is needed for the car itself.
There are two problems to solve: Suspending enough cable outside the gravity well so that it won't fall back to earth, and keeping it 'straight' as it's whirled round 'n round.
Neither of those two things can be tested by a model. At least, not here on Earth, as our own gravity would skew the results.
The car itself, along with the drive mechanism are both proven technology, used in every high-rise across the planet.
So, string the big cable (made of BuckyBalls, perhaps?), mount solar panels up top to take care of the electrical requirements, and off we go.
The really exciting thing here would be if it could actually be built soon enough for Arthur C. Clarke to actually ride in it, similar to the way he was able to use his home satellite dish in Sri Lanka to fax chapters of 2010 to his New York publisher...
It is not in unrestrained orbit. Pitiful really.
I'd have thought megatech or gigatech would be more appropriate for a thing umpteen thousand miles long