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Highlift Systems' Space Elevator In The News Again
Kris_J writes "Highlift Systems may have found a second location for the anchor of their space elevator -- Perth, Western Australia. Apparently we have the calm waters and international airport that it needs, amongst other things. Slashdot has covered this company's efforts before: Oct 9, 2002 and, earlier, August 13, 2002, but it's worth discussing again since '[recent funding] has been given momentum by the Columbia shuttle disaster.'"
you know some jack ass is going to press the buttons for floors 1 -100,000
Once again I'll get modded flamebait for this, I'm sure, but will SOMEONE explain to me how such a thing is supposed to work? What is resisting the downward force of the elevator climbing the cable? What is bearing the load against the earth's gravity? Items in orbit are not nailed to the sky, after all, they're just falling around the earth in just the right way.
Also, could this possible create drag in the solar wind and slow the Earth's rotation? (most likely another stupid question)
Willy Wonka would love this!
Perth also has an extremely large sanatorium to cater for the elevator musak induced madness
Do not try to read the dupe, thats impossible. Instead, only try to realize the truth
What truth?
There is no dupe
"But with a start-up cost of $17 billion, the idea needs strong US and Australian government support."
Lyle Lanley: Well, sir, there's nothing on earth
Like a genuine,
Bona fide,
Electrified,
Six-car
Monorail!
What'd I say?
Ned Flanders: Monorail!
Lyle Lanley: What's it called?
Patty+Selma: Monorail!
Lyle Lanley: That's right! Monorail!
Which just goes to show, if you're asking on Slashdot, then you're either too lazy or too stupid to find out yourself.
How we know is more important than what we know.
I don't know about a space elevator (it is a cool idea and hopefully it will actually happen) but how in the world are we expected to believe that a 100,000 km long elevator will work if they still can't get the simple 20 store elevators to always run smoothly. I constantly see broken elevators at work and in many buildings, hell it would suck to get stuck in an elevator 80km above ground, I can just see it: a dark room with 6 people and some lagguage. Everything is going ok and all of a sudden, 40hours after lift off - shebang, nothing works! So they reach for the emergency phone: -Hello? Hello? Anybody out there? I don't think we are moving any more! Anybody at all? Anybody!
:)
Just like the usual, the mechanics are off for today. It would sure suck to hang up there held by a f...ng thread
You can't handle the truth.
I think they will have to choose the music for this elevator VERY carefully. I mean, how long will it take to get up there? You don't want people to go insane and stuff.
:)
Although, it would make for a REALLY good tv-movie.
.. only under great circumstances do any modern marvels come to full attrition. Unless there is an actual need, be it military or economic, this project will never "take off the ground"
Basically, it would take some sort of War or space race with China for this to even be the slightest possiblity. Tax payers will not vote for a 17 billion dollar project unless it was under dire circumstances or felt threatened [alla China]
Think about all the previous advances in the human culture. So many were spawned from war. For instance, I doubt the common 747 jet airliner would be such a popular mode of transportation today if the Nazi's weren't looking for a plane that could run circles around the allied air force.
This post is going off in a tangent. I guess what I'm trying to say is that with war comes advancement in technology. Without war, technology is backed by monetary gain. What is to gain by building a space elevator? Unless they can mine diamonds or gold from the upper atmosphere...
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Exactly. The damage done by a broken orbital elevator depends almost entirely on where the break occurs. Red Mars had such a terrifically destructive event becuase A) the thing was far heavier than anyone is planning for use here and B) it was cut on the far side of its center of mass. Orbital mechanics dictated that it would go nowhere but down. If the thing had been broken on the other end of its center of mass, then (barring the piece that was severed) it would have gone _up_ instead. Which would make it a hassle to reestablish, but not the latitude-destroying event Robinson depicted so well.
Dyolf Knip
Any local Perth residents that want anything to happen with this project should send a message to the Premier's office using this page. Be polite. (I'm fairly sure this isn't redirected to /dev/null.)
What happened to Sri Lanka? I thought the goal was to get as close to the equator as practical.
The Earth has a much thicker atmosphere than Mars, and atmospheric drag would be sufficiently large to vaporize all of the cable falling from more than 25 km or so. This effectively sets the distance you need to be from the shore in order to guarantee that the cable won't fall on someone in case of an accident.
If you ask me, we put altogether too much emphasis on putting stuff in orbit these days. Manned space exploration has been stalled since the end of the Apollo program; putting people into orbit has become the be-all and end-all. Our focus should be beyond orbit; we should head back to the moon, and then on to Mars. Right now, we are doing fine using disposable rockets to put satellites into orbit, and assuming that the investigation into the Columbia disaster comes up with substantive results and recommendations, the shuttle program can continue to put people into orbit (and we end up grounding the shuttles, I don't see why we can't use Soyuz-like capsules to send people to orbit). If we're planning new space technologies (and major space-related capital commitments) I think we must literally aim higher than Earth orbit. While a space elevator would be an incredible technical achievement, it should wait until we have enough in the way of manned orbital stations to justify the cost, or until private companies want to pay for it as a satellite delivery system.
If we're going to spend that much money on space, we should spend it on space exploration.
I thought that the anchor needed to be on the equator and Perth is aoubt 36 degrees south. I would imagine that there would be really large lateral forces on the anchor and suspect that the cable would be curved.
Nate
Elevators == Muzak
Muzak == Craziness
Moderators == On Crack
Laugh at my Lisp and I keeell you.
Mr. Robinson's vision does not match up with the modern concept of a space elevator. The proposed elevator would be extremely small and thin, as in paper-thin, and would have a very, very low mass/length ratio. Also, it would not be much stronger than required to hold it together in normal orbit. All this means that if it broke near its anchor, it would fracture into lots of small pieces which would then all burn up harmlessly in the atmosphere as they reentered.
The Mars Trilogy's elevator is on a smaller planet with much less atmosphere, and it's apparently also ridiculously over-engineered. (Or maybe it was built with more commonplace materials, instead of carbon nanotubes as is being explored today... anybody who's read the books more recently than I have care to comment?)
In short, don't worry about cable breaks, unless you're on the cable at the time, or you have stock in the elevator company.
Mod down posts with a "Free Mac Mini/iPod" sig, they're spam!
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OK, so I'm not a physicist or a geographer, but... don't these things had to be positioned at (or near) to the equator (like a geo-synchronous satellite)? Otherwise they would sway and stretch because the orbit would not match the ground.
Space elevators are central to Robinson's 'Mars' trilogy as well ("Red Mars," "Green Mars," "Blue Mars"). Highly recommended if you're into Mars. ^_^
And all our yesterdays have lighted fools The way to dusty death. --Will
the heinlen novel "Friday" which describes a system with space elevators that go to the lagrangian points. worth a read any way you cut it though.
"You never want a serious crisis to go to waste." - Rahm Emanuel
wired recently ran an article on this. One key quote is ""Technically it's feasible," said Robert Cassanova, director of the NASA Institute for Advanced Concepts. "
a little further on the cost benefits are addressed, "a space elevator could transport materials into the cosmos for about $100 a kilogram. He estimated that sending materials on a shuttle costs $10,000 to $40,000 per kilogram. "
How would the structure stand up to the ravages of time? Has anyone modelled a nano structure to see what the effects of entropy are?
Do you need a website upgrade?
a rocket gets launched trailing a reel of carbon nanotubes. This original cable is very small, almost useless but it will hold enough weight for a small car to go up it laying down a reinforcing layer. Every three days another car goes up and every three days the cable gets thicker, stronger, and capable of sustaining more weight. Eventually, the entire thing is ready to go and what's the first thing they're going to launch? Reels of full sized space elevator cable so when the original inevitably breaks, it'll take just a few days to reel the replacement down at a negligible cost.
The ease of replacement, more than anything, is what is going to keep the thing off any terrorist's a-list of targets.
Start with an elevator starting in perth, sticking out parallel to the equatorial plane. Have the end attached to a meteor or something (I think it would work the same either way, but this way is easier for me to visualize). Let gravity pull the meteor pull the end of the elevator back toward the equatorial plane, resulting in a sort of curve that starts parallel to the equatorial plane in perth, and ends up somewhat south of the equattorial plane, held in place by tension.
I'm not sure if this works, physics-wise, it's just what I visualized. I'm sure someone here can bust out some equations for us, and tell us what would happen!
as the anchor is moved towards the axis of rotation (south pole) the ribbon begins to extend horizontally from its anchor, but it still approximately parallel to the equatorial ribbon.
the counterweight will settle just south (or north) of the equator due to the south-pulling force from the anchor. no oscillation.
I don't understand how they can base it so far from the equator. If you start the counterweight south of the equator, above Perth, it will be way north of the equator 12 hours later.
In more detail:
In a reference frame rotating with the Earth, the counterweight has three forces on it:
Gravity: G m M_earth / r^2
towards the center of the earth
'Centrifugal' force (because we are in a rotating frame): v^2 / r cos l (l = latitude) directed perpendicular to and away from the earth's axis
Tension on the cable.
We want these three forces to cancel out, so that the counterweight is stationary (in the rotating frame.) The problem is that the gravity force has a north/south component unless the counterweight is on the equator. The centrifugal force can't have a north/south component, so the balancing force has to come from the cable tension.
The cable will have be at a small angle to vertical, and the north/south component of the tension is proportional to the sine of this angle, so that component can't be big.
Aha! I think I have the solution.I was thinking of the counterweight being above the tether point.
In the 1st approximation, put the counterweight in geostationary orbit (i.e. on the equator). Run the cable to it.
If the cable had no tension, we would done - but it does. The major component of the tension is towards the earth. We compensate for this by moving the counterweight into a higher orbit. (Decreases gravity, increases centrifugal force, to balance the tension.) There is nothing new here - the Highlift Systems website talks about this.
If the cable was anchored south of the equator, it will have a slight angle to vertical, which will give a southwards force component. If we now modify the orbit of the counterweight to be slightly south of the equator, there will be a northward component to the gravity vector. We can adjust to balance.
From the point of view of the tether point, the cable (if it is straight) will be pointing almost towards the geostationary point. From 30 degrees south, that would be a point about 3000 km north and about 35 km up, so it would be about 5 degrees off vertical.
Quattuor res in hoc mundo sanctae sunt: libri, liberi, libertas et liberalitas.
This is why most designs count on the bottom of the elevator touching the ground, so that a significant portion of the elevator's weight can be supported by contact with the earth instead of tension in the elevator.
First of all, the tendency to buckle makes it vastly more difficult to build a long structure under compression than one under tension. Building a structure to support the elevator from below would be just like building any other skyscraper; you wouldn't get the top of the section under compression to be more than a mile off the ground, and after that you'd still have 25,000 miles to go.
But perhaps just as importantly, the bottom of a geosynchronous elevator design needs to touch the ground because it needs the base to be pulling down on it, not lifting up. If you want to take a 20 ton payload up the elevator without pulling it down, then the elevator is going to need to be under at least 20 tons of tension at the ground when there is no payload on it.
The above post makes an excellent point, there is currently no material that can sustain the enormous stress that would be required to construct a space elevator.
While there is no current material that yields the necessary strength/mass required in order to built a space elevator, realistic possibilities are on the horizon. Quite simply, with the advent of nanotechnology, we are nearing the technological feasibility of creating a material composed of intertwined nanotubes. This is theoretically the strongest material that can ever be created. Carbon-Carbon bonds are extremely strong and would be extremely densely packed in a nanotube pole. It would be an order of magnitude stronger than steel, as well as significantly lighter.
While nanotubes can already be readily produced (Dr. Smalley of buckyball fame operates a production facility), strong nanotubes rods have yet to be produced. This is due to a variety of technical hurdles that must still be overcome. Perhaps the foremost obstacle is getting the produced nanotubes to lie parallel to each other. The current production method has the nanotubes forming from a catalyst and then becoming intertwined in a jumbled mess. When tension is applies to the mesh, the rope breaks not within the nanotubes (which would require a great deal of energy), but between the nanotubes, unraveling them from each other. Attempts to get the nanotubes to align properly have failed. Nanotubes are not an easy molecule to work with. They have extremely strong cohesion forces and are very difficult to pull apart from one another. The obvious approach of functionalizing each nanotube in order to orient it correctly doesn't work as doing so causes the nanotube to lose much of its mechanical and electrical promising properties.
In addition, when nanotubes are put under extreme mechanical stress, the bonds within the nanotube shift. For example, I've seen simulations where the bonds separating two polygons disappears, creating what appears to be a bonding who in the nanotube. The hole then resonates through the nanotube causing significant weakening in the structure.
At a talk I attended, the most promising idea I heard discussed was a steel/nanotube alloy. The nanotubes would run vertically through the steel, reinforcing the structure in the same way steel rods are often used to reinforce concrete. This would alleviate the risk of the nanotubes becoming unraveled intermolecular while at the same time using their large intermolecular strength to reinforce the structure.
Of course, without any physical models, this is mere speculation. However, it suffices to say that a there are real possibilities of breakthroughs that would allow for the construction of such a space elevator.
The section of their FAQ that discusses the problem of large electrical currents generated by long space tethers was really interesting...
Would it be feasible to create a tether to low-earth orbit for the express purpose of generating electricity? I wonder how the cost would compare over the long-term to other low-cost sources like wind and nuclear.
absolutely not true. the elevator is in orbit around the earth just like the moon or any other satellite. the center of gravity of the elevator is in geosynchronous orbit (36000 km or 6.6 ER) Geosynchronous orbit has an orbital period the same as the rotation rate of the earth. A geostationary earth has a period of 24 hours and coincides with one spot on the earths surface. In other words, anything in that orbit will remain over the exact same spot essentially forever. The elevator goes into a geostationary orbit. Since its long, they can put the cable down anywhere within a 45 degree arc. The only thing you need an anchor for is to keep track of the cable. The greatest tension on the cable is at its center of gravity, because at that point, half the cable above it is centripetally trying to be flung into space, and the other half is trying to fall down to the earth. But this is located in geostationary orbit. Theres little if any tension on the cable at ground level.
I don't get it either. But as some of the other posts have mentioned, it wouldn't be orbiting, it would be getting 'swung' around by the earth.
Would a physicist please correct the following?!
I picture a tether at the equator going out at 90 degrees. If you move down to Perth, the tether will still go out at 90 degrees to the axis of rotation wouldn't it? That is, it would go out parallel to the tether at the equator. See diagram.
X
XX
XXX
XXXX
XXXX---------O equator
XXX
XX---------O perth
X
So, does that mean that it wouldn't be vertical at perth but would go out at an apparent 31 degrees?
Also, does that mean that the thing actually goes over all of the airspace between 31 degrees and just south of the equator? That is, because of the angle, would it actually go over, say, Indonesia's airspace.
Parts of Indonesia are nearly 10 degrees south. Does a line drawn vertically from Indonesia intersect with the ribbon?
Comment removed based on user account deletion
I have some friends that work on creating large (long) carbon nanotubes. As of about 2 years ago, they were unable to make tubes longer than about 1 cm. Things may have improved somewhat in the last couple years, but basically we're about 8 orders of magnitude short of the length needed for a space elevator.
One, if the elevator is to remain in a fixed place above the Earth, the radial force (tension) must balance the inertia. For this to happen, a quick calculation shows that at that latitude, the center of mass of the elevator must be 18% higher than the geosync height over the equator. You'll have to put a massive asteroid into orbit at roughly 30k miles up going thousands of miles an hour to anchor this sucker.
Two, that asteroid will orbit with a 32 degree angle of inclination until it's actually connected to the elevator. I pity the poor fool that has to play catch with that thing in orbit and actually link it to the elevator. If anything goes wrong, the asteroid drops to Earth, bringing devastation on a global scale. All of the previous discussion assumes that the elevator remains perfectly vertical, which brings me to...
Three, if you anchor a space elevator to the Earth at any latitude but 0 degrees (the equator), you're going to have a lateral inertial component, perpendicular to the radial, that'll bend that rope like a taut bow string. Another calculation shows that the shear force on that rope will be almost 53% of the tension. (This is simple trig.) Carbon nanotubes may have a hella strong tensile strength, but has anyone looked at their shear strength? I wouldn't want the thing to snap like a twig just after they get Mr. Doomsday Rock into position to fuck us worse than the dinosaurs...
This post expresses my opinion, not that of my employer. And yes, IAAL.
When you can buy spools of this stuff, it's time to take this seriously. But not yet.
The rock is in orbit above the equator. The elevator starts at Perth. So, the cable/shaft runs at an angle not normal to the earth's surface. It leaves the ground at an angle.
The cable would trace out a cone if it were straight, if that helps you visualize it.
Justin Dubs
Weeeell, yes, just not for very long. I suppose you could build tracks around a meridian and put up with trains constantly hurtling around the planet at over 1000km/h, but it would hardly be economical.
Assuming the original poster was not just practicing rectal ventriloquism, `connected' doesn't mean literally bolted together. You would slingshot a load off the end of the elevator and catch it again on the end of another elevator at the destination. You could also use elevators (even just spinning tethers in free space) to accelerate and decelerate traffic out- and in-bound.
Translation: `I have no sense of scale'. (-:
On top of this, since the elevators are in orbit, they don't make the planet wobble at all (caveat: the mass of the elevators would move the center of mass of Earth, perhaps by a measurable amount).
Got time? Spend some of it coding or testing
People in canoes have been doing this for thousands of years already. It's actually possible to accelerate towards a star, on average.
Got time? Spend some of it coding or testing
Very nicely put. The schoolboy physicist is told that centrifugal force does not exist, so we see it repeated here ad infinitum. The structural engineer (me) knows that the tension in the thread is not a vector, it is a tensor, a two headed vector, if you pass a control plane through the thread there are forces BOTH ways.
A glass of wine with you, sir!
I'm appalled at the lack of imagination shown by most of these posts.
First off if you read the PDF (15M) report to Nasa prepared by Bradley C. Edwards to satisfy the requirements of his $500 000 grant you will readily see that this is totally feasible.
Next check out the website - where they are calling for people to express interest in working on this project. They expect to be hiring in the next year or so. You'll also see that serious people are taking this seriously. Do you want a job?
Next understand that $17B is not very much money. Considering that BP just spent $6.7B on a oil company in Russia and has plans for more purchases.
I meantion BP because they have a plan to move beyond oil.... BP Solar is BP's attempt to become a broader energy company (check out their new sun logo) instead of an oil company. The High Lift systems news page says: -
BP Solar - a subsidiary of British Petroleum, currently doing $300M in annual sales. Our discussions have focused on BP's interest in using the SE for deployment of a solar energy satellite. Several items that came up included possible collaborative efforts, the performance of our system and the possibility of BP using our system. They are considering writing a letter of endorsement
If BP with the cash they have can throw $6.75 B at Russia they could, over 5 years, finance a large share of the Space Elevator. Who needs the Government? In fact Nasa would make sure it costs more to build than it should. Nasa is a bureaucracy, not a business, and is ill-suited to the sort of cost control required of economically viable business decision. Only communists would argue that a Space Elevator should be built and controlled by government.
What would BP Solar do? Build Power Sats....
These are High Lift's vision for the main use for the Space Elevator. Imagine a fleet of these beaming power to anywhere on earth. Every country on the planet could get cheap electricity without the huge national grid infrastructure required now. Without the huge investments in time and resources to build power stations - and without the fossil fuel use.
Use your imagination.
These ideas have been the subject of SF for decades - but the Space Elevator is now possible due to those nifty Carbon Nano-tubes.
When your imagination focussed by the reality of this thing actually being built in the near term (5 years) everything changes - and it'll change for us not our children. It'll change our careers.
Imagine this - an electric airplane that is powered by a Powersat beaming microwaves to it. No fuel to carry, super efficient travel - and at what speeds?
These guys are planning for the Space Elevator to be operational SOON - they have realistic timelines.
What I want to see here is some discussion of the uses that could realistically be made of a space elevator. We're the generation that will built it, use it and be changed by it. I like the parallel to be made with electricity, or flight, or the steam engine - in the early stages everyone probably dismissed it - and the world changed despite them.
What would you realistically (with a nod towards economic viability) do with the low launch costs they're projecting - $10/LB...
Ideas anyone?
Cost of a space elevator: 17 billion dollar Cost of a shuttle launch: .5 billion dollar
Project implementation timeframe: 20 to 30 years
Cost per year = 17 / 25 = .68 billion dollar = 1.36 shuttle launches per year
-- Contradictions only exist in thought - not in reality.
The counterweight is just a long ribbon of the same material.
Launching it requires a rocket launch to past geosynch orbit, reeling out the tether (1mm^2 cross-sectional area) as it launches, the rocket doesn't have to go much past 35k km (geosynch), well at least not the full 65k km, more like 10-25k km before the cable will self unwind to the full extension.
Then a tiny robot (likely solar powered) will crawl up this tiny thread and stick another layer on. And another, and another until it has counterweight capability and strength to lift a 22 tonne lift car and 14 tonnes of cargo. The initial launch is difficult, BUT after that it is just materials and robots... 3 days a piece, after a year it'll be ready... Each robot can haul slightly more cable than the previous robot, which in turn increases its loadbearing capability, and thus more heavier cable... etc...
Z.
This would significantly reduce the appeal for attack that a single space elevator would have.
That assumes that the only reason why the terrorists would attack the ribbon would be to disrupt its operation. However, in reality, terrorists would attack the ribbon for its potential to wreak havoc. If a terrorist blows up a dam, he doesn't do it to deprive nearby cities of drinking water or electricity. He does it to provoke a flooding catastrophe!
Although Highlift's website downplays the effects of a ribbon rupture, somehow I've trouble believing them. If the cable is strong enough to hold up, wouldn't it also be strong enough to slice everything in half that it encounters on its way down? As anybody having worked on a ship can attest, a rope under tension packs a helluva lot of destructive energy, which is released all at once when it snaps. It'll certainly do much more damage than "loose sheets of newspapers".