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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)
Now we'll have some goof push all the buttons on the elevator and ruin it for the rest of us...
Willy Wonka would love this!
Fascinating.
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
The cost to construct, maintain, and protect a space elevator is far beyond what we can get out of one with current technology. How many millions of tons would we have to put up into orbit with an elevator to make it match a hydrogen rocket?
120 chars of filth!
In the article it mentions that this concept could further be extended to bringing people to the moon via these "elevators".
According to my previous understanding of the concept, the force of earth's rotation would "swing" the carbon ribbon out into space. Otherwise the ribbon would be unstable. The ribbon would be anchored to a geosynchronous orbiting satellite.
We might be able to build the same type of device onto the moon and shorten planetary-moon travel, but I don't think we could build an elevator all the way to the moon like the article hints at (at least not with direct application of the technology as is).
Please correct me if I'm wrong on the basic principles of the elevator.
guess the title already says it. The orbiting station would have to be high enough, then the centrifugal force is higher than gravitational force, since angular velocity for geostationary orbit would be the same, but absolute speed is higher, and thats what c.f. depends from.
Maybe I missed something, but why do the requirements put this elevator in the middle of the ocean? Does it have to do with international waters or something with how it is anchored?
As a resident of Perth, I can inform the /. readership that we have one of the most corrupt police forces on the globe, closely affiliated with international mafia. Just be careful what you do here, as you are likely to be framed, murdered or assaulted by our police. Read transcripts from our current Royal Commission into police corruption: http://police.royalcommission.wa.gov.au/
"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.
If funding is a problem, I can easily "throw away" a few billion on this project ...
Cyde Weys Musings - Scrutinizing the inscrutable
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.
As a resident of Melbourne, hey couldn't be worse than Sydney cops ;)
Any sufficiently advanced technology is indistinguishable from a rigged demo
--Andy Finkel (J. Klass?)
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.
The cops are doing a great service supplying smack, whipper, chiba, and disco biscuits.
Be thankful, nerd.
Main Street's stil all cracked and broken!
.. 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...
Live web cams
Assuming and hoping my basic math isn't off here, and the article meant to say 100,000m, not 100,000km. Given that the Earth's diameter is less than 13,000km, that would be one hell of an elevator - imagine an orange with a string the length of your forearm coming off it.
100,000km would be almost a third of the way to the moon, right?
Maybe the plan is much more ambitious than I thought...
-- http://frobnosticate.com
Everyone else has explained how the elevator climbs, but I have not seen an explanation of how the horizontal forces will be handled. As the car climbs toward the sky, its angular velocity will remain constant, but the distance from the center of rotation will increase. The resulting increase in angular momentum will require a torque. How will it be applied through a flexible cable?
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.)
Note you'll also need inertial dampeners to quell the dramatic speedups/slowdowns for mere mortals.
Yeesh. It really IS that big?
I always thought this thing was going to just tickle the atmosphere. I was off by a factor of 1000.
Wow.
When can I get a ride?
-- http://frobnosticate.com
My understanding was that a geosynchronous orbit has to be above the equator. Perth is at about 32 degrees south. Does the elevator point up at some angle? I imagine it might stick out perpendicular to the earth's axis of rotation rather than the surface.
What happened to Sri Lanka? I thought the goal was to get as close to the equator as practical.
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.
The 747 and Nazi's?
This is spawned from one of those expert trolling checklists isn't it?
...people will be sending emails to one another listing "50 ways to annoy people in the space elevator"...
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.
the biggest problem that I see is that the tensile strength of no material is good enough to make it thousands of km long and suspend under earth's gravity. at 1000 km alone, we would be talking about 10,000,000*density/m^2 tension on the fiber. If the fiber is made of steel, then we are talking about hanging 80 ton truck to a millimeter thick fiber (or imagine a small car hanging off a wire of human hair thickness). Granted, the material would be lighter than steel, but then the length would be considerably greater than 1000 km. I would surely want to see a demo of millimeter wide fiber holding 80 ton truck.
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.
Kim Stanley Robinson has a space elevator on Mars in his novel "Red Mars" (1993). The way it worked was they got an asteroid/moon and mined the materials there to make the elevator. They had to get an asteroid that would be the proper mass _after_ the elevator was finished. They built the elevator cable/tube thing down from the asteroid, which was in geosynchronous orbit (martiosynchronous?) over the martian equator. When it was finished the elevator had two cars that were on one cable, one going up while the other went down (like a funicular cable car, such as Angel's Flight in Los Angeles). In the end Martian separatist terrorists who were trying to get out from under the imperialist subjugation of the earth blew up the cable at the asteroid side. It then came whipping down to the surface of Mars obliterating everything in its path. Robinson has a way of explaining things like this that have you believing it could be possible. He borrowed a lot of ideas from NASA types and the Mars Society in writing the novel, such as terraforming.
Wouldn't this be a prime terrorist target?
Don't give me any BS about it being way out to sea with the US Navy protecting it. I don't think it would be that hard to sneak in a radio controlled aircraft w/ onboard GPS and loaded with a few pounds of plastic explosives.
More info if you are interrested can be found at http://science.howstuffworks.com/space-elevator.ht m
It's my experience that modern marvels come to full attrition in a distressingly short time.
KFG
Just remember how crazy a moon landing must have been seen in 1955. I'm not saying that they'll actually be able to build it, just that it would be an absolutely astonishing thing if they manage to do it. And unlike the moon landing, this will enable future exploration.
If tits were wings it'd be flying around.
Do you first attach the outer end to something and pull the string down, or do you attach the bottom to Australia and tie the other end to a big ol' rocketship?
many pharmesuticals can be made in space... chemicals can do interesting things when not disturbed by the earths gravity.
there are any number of commercial applications in space, manufacturing is just one (and many)
-------
Interior desgin and wallpaper australia
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.
Now what we need is something like this that the glass bottom doored opens up on: the world's longest waterslide :-)
Never, ever lose a file again. Ever.
So what's going to happen when the Romulans go flying by and decide to try to tow the earth into the sun?
The man who trades freedom for security does not deserve nor will he ever receive either. - Benjamin Franklin
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
I think eating beans would be a good start to the list. With enough gas, they wouldn't even need an elevator, they could just float up!
>What is to gain by building a space elevator?
> Unless they can mine diamonds or gold
> from the upper atmosphere...
Would you settle for:
Cheap communication?
Cheap, almost zero pollution, electricity?
Cheap iron ore with NO pesky environmental restrictions?
Cheap surveillance satellites?
The possibility that you could somewhat influence the weather?
A new era in astronomy?
Total air superiority? If someone annoys you, you take the tailings from your cheap iron ore, make iron balls the size of an the Arc de Triomphe, and drop them on their heads for a while. They can't even intercept them, too much mass. If you're after a mobile target, substitute an iron rod with a camera in the nose, stubby little wings, maybe some attitude correction thrusters in the tail. How would you like to dodge those going by at mach 12?
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
I can imagine a 100,000km elevator coiled up in the australian desert, then a shuttle launched with it tied to the back. The huge coil slowly unwinds, only to be dragged across Australia, levelling perth!
In about 2100. Although I think that's the estimated start date of the project.
Just the base tower is going to be 30 miles high, the cable itself is going to be collosal.
By the time the carriage reaches the end it should be doing about 7 miles per second.
I just hope the music on the elevator isn't the girl from ipanema looped.
Once this would be built, how do you protect the length of the ribbon from attack???
The cable is going to be 90,000 miles long. The carriage doesn't have to go all the way to the end, but it can do - and beyond.
The cable stretches a third of the way to the Moon. You could get to the end, open the window and spit into the Sea of Tranquility. Well, almost.
When the car reaches the end of the cable it will be travelling at about 7 miles per second - fast enough to get to Mars in weeks, not months. It would also be cheap, so you could send a lot all at once, or every few days assuming the aiming/steering mid flight could be sorted out so you'd actually arrive on Mars.
Once we've been there, the rest of the solar system would be a snap.
>>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.
>The 747 and Nazi's?
>This is spawned from one of those expert trolling checklists isn't it?
No, he's right about that. Germany created and flew the first jet fighters. Unfortunately for them, the war was almost over already. Commercial jets are descended from those planes.
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?
It's essentially a very vulnerable and exposed chain. And we all know wbout weak links and chains.
Ok, two more for those of you who don't INSTANTLY see the problem: Thin wire.
Is it fascism yet?
I'd rather the money to be spent on social programs and be used to confiscate guns and imprison gun owners and drug users and dealers and to support Israel then be wastefully spent on a "space elevator."
which probably makes it a good choice in case of accidents. Recalling my high-school physics (way too long ago now...), if the whole thing collapses while being put in place, the rotation of the earth should mean it would fall to the west, and there isn't much west of Perth for quite a way (i.e. Africa).
Of course, if a 100,000km piece of very strong rope collapses, Africa probably won't be anywhere near far enough away. When they're designing the fail-safes for this thing, maybe they can give some thought to having it collapse in some sort of spiral shape - maybe with a 50km or so diameter. Anyone clued up enough on this to be able to say whether that's feasible?
>>How would the structure stand up to the ravages of time?
They give it a thousand year life expectancy, but realistically we don't know.
>>Has anyone modelled a nano structure to see what the effects of entropy are?
We can't model them yet. All we have so far is theories. They do state that they'd start by just sending up cargo.
How can the anchor point be anywhere between +45 -45 degrees? The space elevator basically runs between a fixed point on the Earth and a point in space that is slightly beyond geosync. A geosynchronous satellite must be directly over the equator in order for it to be stationary relative to the earth. If the satellite was placed in an orbit that revolved around the earth every 24 hours but was in an orbit that was 45 degrees below the equator at one point then the orbit would would trace an elliptical path over the surface of the earth between +45 and -45 degrees latitude. This would be very bad for a space elevator as the distance between the anchor point and end point in orbit would be constantly changing. Am I missing something or is the article in error...
a tellites/geo-high.html
The FAQ on the High Lift Systems site mentions that the first anchor point would be in the Equatorial Pacific. That claim seems much more in line with Physics than Perth.
See this site from an explanation of a geosynchronous orbit: http://liftoff.msfc.nasa.gov/academy/rocket_sci/s
Well, I'd been going to go into an analogy for how it works, then I thought nah, it'll be understood. Oh well...
-- http://science.howstuffworks.com/space-elevator2.
And if everything didn't go as planned .... ? From all the information I've ever seen, we've been more worried about moving asteroids away from earth, for obvious reasons.
...
...the Red Sea! Oh, wait...terrorists in the area...well THAT sucks.
- needs water
- near and international airport
- close to the equator
Kickstart
The "geostationary" won't work - it will oscillate north and south between Australia and probably someplace like Mongolia or Siberia.
Was it Arthur C. Clark's "3001" or whatever the last sequel was called?
At least that way I'd only have to read one story on Slashdot about these scams. The only thing missing was the address to send my investor money to.
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.
Imagine how much voltage would be across the ends of a 35KM long carbon (conductive?) cable being swung through the earth's magnetic field.
Like a collosal version of the space tetherexperiment.
You might not need those solar power sats.. anyone care to do the math ?
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.
Carbon nanotubes may have a longitudinal tensile strength of 200 Gigapascals, but what about the strength of the transverse bonds connecting one carbon tube to the tube next to it? Those transverse bonds may not need to withstand 200 Gigapascals of force, but they still have to be damn strong. A split in a wooden board can travel the length of the entire board. Would a split in the space elevator ribbon cause the whole ribbon to become a series of parallel threads?
My math is horrible but is 100,000,000 (or appox 1/6 the speed of light) miles per hr about accurate.
Current speeds are at 120,000 and that's using gravitational pull from planets. Could really shorten up the solar system. I find the idea a little unnerving compared to being strapped to a couple of hundred tons of explosives, but...
But remember, this has to go through approvals in corporate cubicle meetings where there will be little tie-wearing certificate-whore pussies whining "ehhhhhh why do we need this.. waaahhhh too expensive waaahhhhh it's non-standard... waahhhhh I want new colorful icons to spend money on" right before they go to some trendy tile-covered restaurant to gorge themselves on shitty food and margaritas, flirt unsuccessfully with the too-white waitresses and congratulate themselves on what total fucking shitstains they really are.
Therefore it will never be built.
Thank you and good night.
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.
+5 Insightful
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.
This is not intended as flamebait, only a reminder that we need to take baby steps before we will ever achieve this, and for the record I think a space elevator makes a lot of sense.
For starters we haven't even made an elevator or a building that can go as high as 500 floors. I think we should create a single elevator cable capable of clinbing this height. I heard somewhere that China was going to make real-life arcologies but I haven't seen the proof yet.
The anchor would need to have its own method of maintaining its proper orbit if something awful were to happen. Imagine the space-elevator car weighs too much and causes the anchor to fall to earth. Or imagine the anchor is too heavy and causes the cable to snap. I'm sure Engineering/Marketing types will assure us that will never happen but could it? It would be interesting to see if the cable could be used to gather electricity from the atmosphere and use that to keep its position somehow (ion drive).
Enduing the effects of the atmosphere. I just learned recently that the atmospehere is a highly corrosive region. This would no doubt have bad effects on the cable especially if it were made of [carbon] nanotubes. It would be neat if the elevator could repair the cable during its ups and downs like a street-washer while driving.
Lighting: this is both a good and bad. You could possibly harness the power of lighting this conduit would provide but I'd hate to be in the car going up when it strikes.
How to get it straight in the first place?! I don't think this will be like spinning your wrist to make a string with a weight straight. It would most likely be unspun from outer-space and I don't think it's going to come down in a good mood. It would most likely be whipping around like crazy in the wind. If we stick a weight on the bottom to make it drop a little straighter it could be disastrous. Imagine a giant alien whip hitting buildings over. In that case I'm all for Perth being the location. Also, like the lightning warning, this thing would probably be so charged coming down that when they got it in the water somewhere it would zap al lthe fish in a 10km radius.
I do hope of course that these can be solved. I'd like to go to space one day and don't think I'd want a giant firecracker under my seat.
This means you... and you didn't use them correctly either... consider your status ASSHOLE^ 2 (pronounced "asshole squared."
"...Perth, Western Australia. Apparently we have the calm waters..."
erm....so those annoying "roaring 40's" that destroyed like hundreds of ships over the last 200 years isn't a problem then?
After reading the FAQ by this company, I still can't see how this is going to work. Let's do some physics, shall we. Maybe someone will enlighten me.
/r
The elevator *and all of it's parts* are to be in geostationary orbit. So, figure out what speed is required to keep something in orbit around the Earth at distance r from its center.
m_E : mass of earth
m_e : mass of elevator element
G : Newton's const.
r : distance from center of Earth to elevator element
v : speed of elevator element
Because gravity and centripal force have to cancel,
G m_E m_e / r^2 = m_e v^2
or
G m_e / r = v^2
So, if you are at distance r from the center of the Earth, you need
v = ( G m_e / r )^(1/2)
of speed to stay up. Note that as r gets bigger, v gets smaller. Now, to be in geostationary orbit, one needs to relate v and r like so:
v = 2 pi r / (1 day)
and one gets the answers for r and v. (something like r= few 10^5 kms and v = ~7km/s.)
Because this elevator *from top to bottom* has to be in geostationary orbit to even exist, the bottom part will be moving too slow and the top (if it goes past the geostationary point) will be moving too fast and will want to fly off. To keep everything in check and together, some bad ass rope has to be used.
Let us assume one can get something that is 1) strong enough so it all stays together and 2) light enough so the graviational pull of the lower part of the rope doesn't bring everything down. (Remember gravity gets stronger as you approach the earth.) We now have a perfect system in theory and if all there was in the Universe was the Earth and the elevator, it just might work, and once you have it built, don't touch it because if anything changes in v or r, the whole thing will come down if it doesn't snap off first.
What I mean is, the whole elevator is going to be undergoing perturbations from a number of graviational sources like the sun and moon. The platform will have to have some thrusters on it to *constantly* correct for these perturbations and also for the load that is being hauled up the rope. Can you guess how much energy you might need to compensate the load on the rope when something is going up? Think about energy conservation. It'll be alot like the energy needed to put the load into orbit via run-of-the-mill rocketship.
So, to me it just doesn't look feasible (ie worth it). Feel free to tell me otherwise.
PS. This would be an awesome thing to put into some mechanical simulation software.
If you don't believe me, ask that guy over there.
i think it's funny what he was doing when the officers arrived... i always found him to be a pretty cool guy... he was on the daily show with craig kilborne once and he was obviously drunk off his ass... his speech was all slurred and stuff...
;)
also notice how the cop called himself a "peace officer". i wonder if that's because in texas they can't say "police" with the accent.
Yes, it would generate power, but perhaps that power can be used to lift objects off the Earth. I hope the ribbon can withstand the differences in electrical potential. (The US-Italian space tether failed because electrical flow along the tether burned through the insulator, and broke the tether.)
Riding down the ribbon would also generate power since gravity would convert potential energy to kinetic energy. Which means the cost of raising something off the Earth could be far more than the cost of sending something down to Earth. (A one-way passenger ticket down might be cheap.)
For any Perth people that want to get involved, there's now a forum at www.e3.com.au (a website about Perth's free/community wireless network). A big thanks to Jason at that site. I've also made a tiny URL: http://tinyurl.com/5xy2 for signatures, etc.
Just because you know science fiction does not mean you know science. Stop, for the love of god, posting stories that are not news, are not interesting, and have no scientific value.
Hey I've got a great idea! Why dont we post a story about a company that wants to build a space elevator! Never mind the fact that we do not have the technology, the money, the need, or the desire to build one at this point. If it was in Alpha Centauri, it must be months away! Sid Meier wouldn't lie to us.
As soon as someone stops theorizing and starts building, post that. Until then, don't give assholes trying to scam money the tools to do it.
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.
Actually, I was thinking that there are private companies that would be excited about such a concept. We're talking a monopoly on affordable space travel, and on top of that, think of the possibilities of mining etc. It would seem that space travel would actually be quite affordable once you got past our atmosphere, since I think the current shuttle uses over half of it's fuel just on getting out of the atmosphere.
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Vive l'appeasement!
Hooray for Michael! Three cheers for Timothy! Maybe we'll get to be the 51st US State after all!
Don't shuttle launches cost in the range of $20-30 million? I think $160000 per person is still a lot of money for "tourism". Why should we invest huge amounts of public money so that a few rich people who can afford to blow $160000 on a summer vacation can have their thrills?
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okay so i get the basic concept of how it stays in place and is balanced and all, but what about the thing that climbs up it, wouldnt it still be subject to gravitational forces and require lots of energy to move upward along this ribbon...???
read the tech specs, it's in the design parameters
What happens if terrorists try to bring this thing crashing down to earth?
We couldn't build a 62nd street subway tunnel in 30 years. We take more time to paint bridges than it took to build them. Narita airport is actually sinking into the sea. It takes longer to fly somewhere than it does to drive if the trip is less than 350 miles. The Chinese may or may not have used atomic bombs to clear earth for their 3 Gorges project.
And you want to embark on the largest construction project ever, to go to space? Yeah wake me up in the 27th century.
...they run commercials!! Hell...all the companies in the phone book could run their stuff by you by the time you get there :)
:)
And, ofcourse, all this would done to "enhance the customer's experience" hehe
Find a job you like and you will never work a day in your life.
In the series Red/Green/Blue Mars by Kim Stanley Robinson he used the same idea to thicken the plot of the book, including making the space elevator fall crashing into the planet. I wonder if the company looking into building this is also looking into the possible 'terrorist' attacks on it. ... Having a cable come falling back to earth, wraping around it crushing whatever lay in it's path doesn't seem like a good thing to me. However, I'd love to ride up on it to a space station.
there are so many other elements working against the space elevator, and these are examined in the design study located here
p or t/pdf/472Edwards.pdf
http://www.niac.usra.edu/files/studies/final_re
it is a very interesting read.
Put the orbit a little higher or lower than geosynch, and the cable's end would wander above the surface of the Earth. Or use a totally different orbit to have it wander in other paths.
The extreme design of this, of course, is the "skyhook". Put the orbital weight near the atmosphere and spin it, letting the ends of the cable sweep through the air. Make the cable move at the speed of an aircraft, and an aircraft can grab it and get pulled into space as the rotation continues. Aircraft taking the downward ride keep the spin rate up...and if more weight is going down than coming up the orbital weight will be getting a boost to keep it it orbit.
Ya know, I was about to flame you mildly, but then actually stopped to think about it for a second, and I realized that there might be some substance to your snark. There does seem to have been a disproportionate amount of "news" about Australia on /. of late.
I'm not against true news, no matter where it might be from, but why do we seldom see items from/about, say, Denmark, or South Africa, or maybe Thailand? If it's not about US news, it's Australian. Hell, we don't even see much of anything from the UK.
I'm sure this can't be due to a lack of interesting events in those countries, so maybe you're right, and Michael and Tim *are* favoring their own land at the expense of others (and those nations interesting stories).
Oh well, I doubt we'll ever know -- I'm sure this'll be modded down to (Score:-1 Flamebait)...
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.
wait, yes I can, I've been sitting in the same chair for 8 hours talking to Americans who cant figure out how to use their freaking CELLPHONES!!!!!!!!!
tcpa SUX!!!!
All it would take is one guy with a pair of scissors to send this thing floating out into space. Or an airplane at any altitude.
Or (since we're talking about the not-to-distant future), dozens or hundreds of stupid little drones released from a cargo plane. (I don't know how feasible it would be for third-world vandals to acquire such things....)
The simplest alternative is a 40 km high or so building, which doesn't require fanciful special materials but can be built, theoretically using current commonplace materials. Accelerate space capsules magnetically up a shaft and use a small rocket motor to give the final boost (or a tower based laser). Most of the effort of placing objects into orbit occurs in the lower part of the gravity well so this would have the benefit of getting much of the advantage of a space elevator for a fraction of the cost.
And build it from the Earth's bulging equator for max benefit of coriolis forces and gravity assist.
See Robert Forward's "Indistinguishable from Magic" or Jerry Pournelle's "A Step Further out", Arthur C Clarke's "Fountains of Paradise", Charles Sheffield "The Web between Worlds".
I don't know about you, but I feel a bit anxious when I take an elevator up a tall building. Or who hasn't felt a little nervous taking a trip up a large structure like the Eiffle Tower? Who hasn't gone on a roller coaster and felt all tense as you climb that first steep hill? Now you want us to take a trip up into space on a ribbon? I don't know about you, but someone would have to knock me out on the ride up. Or even better, don't put any windows on the darn thing and climb slowly so we don't get any idea what altitude we are at!
How long would it take for the elevator to get from Earth to orbit? How about to the moon? How about from the moon, to Venus, or Mars? Would this elevator move faster or slower than current shuttles/rockets? Also, what happens if the elevator gets stuck halfway up, in one of the upper layers of our atmosphere? How exactly would they get to it, knock it down, repair it, or whatever?
Defender of Microsoft and Communism!!!
..doesn't space still have a lot of random stuff in it, atoms of hydrogen or helium and whatnot? Seems like I was reading that was one theoretical way to make a really fast moving craft, but the catch 22 was you had to build up enough speed so the scoop was scooping in enough atoms to use them for fuel, then the fuel burning increased the speed, more stuff scooped, and etc. I guess with the sail you could store it up, then have a full fuel load when you wanted to brake and manuever. Of course, with the sail out front of you, it would be hard to scoop. ...oh well...
--left some out. Here's some more from memory, and I know I'll forget some too. Somalia, Sudan, colombia, bolivia, peru, phillipines,el salvador, haiti, dominican republic,costa rica, cuba, guatemala, chile, pakistan, laos, cambodia,thailand, korea, lebanon. All places attacked or fought in and around with US dotmil troops, paramilitary spook troops, or contract mercenaries, since the end of the last lawful declared war. I'm sure there's a lot more places, those are just the larger more public ones I can readily remember to add to the list. And yes I could easily find them on a globe.
We have a rather excellent constitution,a pity it's just a quaint historical record.
When you can buy spools of this stuff, it's time to take this seriously. But not yet.
...and `Estimated time to exit: five weeks. Please carry adequate supplies of food and water for the journey.'
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After a few km, the waste would be pretty well dispersed. Coriolis and other effects would carry it well clear of Perth, to say nothing of wind etc. From, say, 70 or 80km up, it would arrive conveniently freeze-dried.
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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).
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It seems to me the hard part is getting hold of something of the right mass to tie the top end to - would the ISS do - its not like its particularly useful for anything else. If it wasn't massive enough then what about all those Iridium satellites ?
People in canoes have been doing this for thousands of years already. It's actually possible to accelerate towards a star, on average.
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a tower that will reach the skies? :)
isnt this the realization of the tower of babel vision?
I wonder if they are going to get Schindlers Lifts in to make this thing.
The cable may well not hit anyone, but if it happened during daylight hours, Perth's excellent beaches might get a bit, er, stained...
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"but, it is actually the car pulling the trailer, not the other way around"
This is in direct conflict with Newton's 3rd law, please explain.
Also, in a rotating reference frame (such as anything fixed to the surface of the earth) masses do experience a centrifugal force.
What is the difference between a 'real' and an 'apparent' force?
Are you a Creationist too?
I've got all of the patents. I didn't build it because nobody could want more than 640 kilometers of the stuff. I'll lease a non-exclusive set of patent rights to you, but as usual the software will cost more than the hardware and will probably crash. But you will be getting it from a single source, we do offer tech support (for an extra fee), and we'll throw in MSN membership for free. Oh, and you'll also have to build Palladium into it to guard against terrorist sabotage.
Yes, as a matter of fact, I _am_ the "My" in "My Computer"
i saw a post some where - i forget which - about how only people who speak english with funny accents get considered at /. and anybody from countries that don't speak english as their first language can fucking forget about a mention. heck, it made me laugh!!! but how many interesting stories from lars or mobutu or kwan get dumped so that ones from english-with-funny-accents countries can get posted?
/.
the old grey
she ain't what she used to be,
ain't what she used to be,
ain't what she used to be...
Huge amounts of static electricity would be generated.
...why the Russians shot one down.
Yes, as a matter of fact, I _am_ the "My" in "My Computer"
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!
Christmas Island, of disturbing pictures fame, is run by australia and close to the equator. But despite asylum seekers' notions to the contrary it lacks a decent deep-water port.
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?
I don't know how much electrical potential between the geo stationary orbit and the earth is. But if it is high enough, it could work like a giant battery.
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.
True, and the first rocket fighter, the Messerschmitt Me-263 `Komet' and later the Bachem Be349 `Natter'.
That wasn't the problem. The problem was that Hitler was a gonzo and first prevaricated, then ordered that they be built for bombing - which they were mediocre at, rather than air defense - which they were good at. Mind you, some of the big Yank prop planes could still catch them and shoot them down with a diving start.
No, commercial jets were quite different in design from the start. The British Meteor jet fighters did look quite similar to the 262. However, many of our modern rockets are descended in one way or another from the V2.
The really innovative German 'planes were the Blohm und Voss models. My personal favourites are the asymmetrical 237 and mid-engined mid-propped 192, although other models like the 111 and 170 have their own special shock value too. (-:
Got time? Spend some of it coding or testing
It doesn't require torque (at least not in the way you seem to be saying), its angular momentum about the centre of rotation, in this case the earth. Which means that it will start to pull the cable back along the rotation of the Earth, however the tension in the cable will attempt to put the cable to rightangles to the planet, thus if you go slow enough it will work fine, you are just stealing momentum from the rotation of the planet. Thus the flexible cable isn't an issue...
Z.
Centrifugal force is the one that pulls muppets to the side of the car round corners
Centripetal is the one that pulls on the as of those in the know, in order that they actually get round it.
My spelling isn't bad, I'm evolving the language
When this thing fails, will it fly off into space or fall to Earth? I mean, however light these nano-tubes are, there's tens of thousands of miles of them.
I've listened to some scientists close to/in the company on Radio 4's (a UK factual radio station) Material World program and they seemed to be a little too keen on the theoretical cool stuff and less bothered about the practical details.
Rob.
He-ey! I mean, has anyone asked what Perthites might actually -think- of this? Mobile phone towers are ugly enough, but you can't mask a 100,000km high tower as a palm tree without someone getting a little suspicious.
I, for one, will be the first in line to press all 100,000 buttons and watch the ensuing chaos.
-b
We're all gonna die!
RTFWP! 1-5 years from today for technology to mature and test, 6 years to construct.
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...and what are you doing posting during work hours anyway? (-:
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Pitch the skydiving and tourism possibilities to dear Mr Gallop and see if you strike paydirt. (-:
All hail the mighty Ter^H^Hourist Dollar! (-:
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Wrong. Geosynchronous != geostationary. Geostationary implies an infinitely thin ring around the equator, geosynchronous implies only keeping pace with the Earth's rotation, and even that can be done sloppily.
Perhaps you're really the 999,999th monkey? (-:
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And the book was Fountains of Paradise, I've still got a copy somewhere.
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We can already do that for less using not-much-beyond V2 technology and without the $17G flagfall.
True, the nice elevator will drop costs well below Mr Walker's $1300/kg and will loft up to 22t in one chunk (instead of 2t), but we should be trying both methods in parallel, walk before we run as it were.
For $0.5G/a (ie cost of about one shuttle flight per annum) we can loft over 700t each year using existing technology. It's hard to see why we don't.
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...which is an 8-fold improvement, using existing technology. I can't see why nobody has done it. It's cheap enough that even Australia could do it.
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The end would probably describe something like a figure-8, on about a 7-hour cycle. Might be helpful for doing polar and other non-geosync placements.
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It'd probably be worthwhile keeping a complete spare elevator kicking around in a can in orbit, unwinding all strands at once you could probably deploy a replacement within a week if one broke or got terrorised.
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Wrong wrong wrong wrong wrong.
Physics of Sailing
You can't tack in a solar wind because there is nothing to provide sideslip resistance like water does for a sailboat.
Unless you use chemical engines, but then I'm pretty sure you'd be better off dropping the sails if you wanted to to head towards a star.
A terrorist would have to hit a non-metallic target only a meter or two wide from a distance of many kilometers with something quite substantial.
Basically, anything big enough to do serious damage (like an air-to-air missile) would be so much cannon fodder for a space-based laser array or (close to the ground) even a perfectly ordinary Vulcan. And would require very special targeting software. You couldn't port a laser big enough to do real harm unless you were prepared to power it with a (suitcase?) nuke, and be damn sure your aim was perfect (you only get one short shot, after which defenses wouldn't be a problem for you).
And of course, there's not much point once we get a dozen or so elevators up and/or spares in orbit.
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And that part would have about the same impact as loose sheets of newspaper.
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Most geosync satellites describe something vaguely reminiscent of a figure-8 over the surface. Geostationary stays (more or less) in one place.
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Infeasible.
It would leave pretty much straight up, and curve in a part-spiral (possibly right across the equator before it hits geosync, I don't know enough maths to say in detail).
I'd better take some more sunset photos before they all have a black line in them. (-: Yes, I know it would be invisible at 20km :-)
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And...
No, 35 thousand km up. And the elevator would be curved.
Perhaps someone should point out to them that Cairns also has an international airport, and Cape York has already been proposed as a spaceport. On top of that, Australia plans to develop Christmas Island as a spaceport, too.
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This is very serious, and the answer is "you can't". You *could*, however, make it strong enough that terrorist attacks or earthquakes were unlikely to knock the thing down.
For this very reason, I suggest building bottom up. That is, start by building towers in a bunch of regions, and use the towers to launch rockets.
This *can* be done if the compressive-to-tensile strength ratios approach one. Indeed, looking here or here (for pdf), we see that this is likely the case, as long as your purity is pretty good.
Such a bottom-up construction has several advantages: (1) less likely to suffer a catastrophic failure. (2) thickest at the ground, where terrorist attack is more possible (3) economic advantage to the company that constructs it *before* the project is complete, because there are huge weight savings to be had launching your rockets from even an altitude of 10 km -- so you get customers from the getgo (4) you get to test the things out extensively (5) you end up with an ideal latch-on point for the space elevator when you *do* construct it (6) you end up with a cheaper space elevator to boot, because you're launching your materials from a much higher location. (7) You have one heck of a tourist resort even before you get into space: "Hotel in the sky" whenver launches aren't being carried out.
Correct Horse Battery Staple: 72 bits of entropy. Enter "Correct H" into google. When it generates the phrase, that's
Dropping along the ribbon from geosync and detaching just before the counterweight would give you roughly 7km/s of additional boost (on top of the 4km/s at geosync), which about equals escape velocity for Earth, and would have no problem getting to the Moon. You could do it in an unpowered vehicle if you didn't have to arrive gently. (-:
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Now that we have some context, cheaply built and frequently launched dumb H2/O2 rockets can lob 2t payloads for rougly $1300/kg, so there is a big improvement available with existing technology which we could have on the hop in about two years, but that hasn't been taken.
HLS' elevator requires 1-5 years of development (realistically 2 years) and six years to construct. If it drops freight rates to LEO from $10,000/kg to $200/kg, it's a bargain. It would still be a bargain if it only dropped rates from $1300 to $200.
Moreso since it can be used to launch its own replacement, making the second elevator much cheaper, and the third-and-on much cheaper again.
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Any of a dozen posts above yours point out that it would have about the same impact as sheets of loose newspaper. Mars has little atmosphere, and Kim seems to have seriously overengineered his elevator.
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What asteroid? HLS aren't proposing to use an asteroid. Their anchor would be in the tens-of-tonnes range. Read The Fine Page before commenting.
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Models have been tested and found to work which are nothing more than a shaped piece of aluminium. The device focusses the microwave beam landing on it into a very small space, heats the air there to amazing temperatures and basically operates as a continuous-flow ramjet. No moving parts.
And if someone hijacks the airplane, turn off the beam from outside. Hijackers then have three choices: surrender, crash nearby or deploy parachutes.
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Nah, Kim Beazley'll pinch it for South Oz so he can win a State election there instead of having them built just across the bay from the base that's going to use most of them, the Croweaters won't know how to build the damn thing, and it will still want to sink unpredictably after a $70 million dollar refit, while a safer, quieter, cheaper and more reliable model sits on drydock in Fremantle.
Oh, sorry, I'm having a flashback. (-:
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One set to dig a hole for when you arrived, and one set to fly Toronto away from all that great skiing.
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AFAIK tradition geostationary orbits are above the equator.
Afterall a geostationary orbit above the southpole isn't a orbit at all. IE a geostationary satellite above the pole, would not be orbiting the earth, it'd be spinning on its own axis.
AFAIK tradition geostationary orbits are above the equator. But Perth's not on the equator
Afterall a geostationary orbit above the southpole isn't a orbit at all. IE a geostationary satellite above the pole, would not be orbiting the earth, it'd be spinning on its own axis
G. Harry Stine gave it guite a bit of ink in the "Destinies" magazines/books back in the late 70's/ early 80's. If I remember correctly, his concern was suitable building materials (what may be optimal @ 10,000 feet may not be at 10,000 miles). Tether weight was a huge problem in his calculations.
So, I'm remembering a fairly horrific description of a space elevator failure in Kim Stanley Robinson's "RGB Mars" books ("Green" I think...).
The gist of it was that the cable was broken, and wrapped itself around Mars (faster and faster). At the end, the impact was producing as much energy as an atomic device.
Now perhaps Earth's deeper and thicker atmosphere make things different here, but as I recall, Earth's gravity and the scale of an earth space elevator would also be larger...
Just wondering. Can a physics guru help?
--- Corporations Are A Fad.
Why would you run an elevator from Australia such that the tether is parallel to a cut through an arc of latitude? That's not the way it works. You run from the center of gravity.
Think of it this way: No matter where the elevator is placed, the cable is (roughly) an extension of a line that is normal to the surface (and, of course, passes through the center of the Earth)
Now, that's an approximation for several reasons. First, the Earth isn't really a sphere, it's a bit flattened. Second, the cable will end up being slightly bowed near the Earth due to wind resistance. And third, the center of the Earth isn't the center of gravity: that's where the point the line would pass through would really be.
Perpendicular to the axis of rotation of the earth isn't really necessary.
Oh, one more thing: In a cable, there isn't any shear (yeah, approximation, but close enough). Any net shear forces will end up bending the cable, not snapping it in half, unless you localize it. When wind snaps a cable, it's not because there's so much wind the cable breaks. It's because the wind bent the cable so much the bend cause the tension limit of the material to be exceeded.
I'm not shy, I'm stalking my prey
Good lord - will someone read Kim Stanly Robinson's Mar's Trilogy to see it's suppose to work.
I can multiply, really: that should have been $40000 per person per launch.
FAQ: Would the elevator be susceptible to a terrorist attack?
Yes- so is practically everything. An attack on the ribbon is unlikely because of the anchor station's isolation and the relatively small amount of casualties that would result. Its main protection is being so hard to get to, there is no way to sneak up on it. However if everyone has equal access to the benefits of the space elevator, there is substantially less risk.
The anchor is located in the equatorial Pacific 400 miles from any air or shipping lanes. The ribbon would also have restricted airspace around it. The ribbon and anchor would be protected like any other valuable piece of property, in this case probably by the U.S. military.
Hmm... I think it's too idealistic. NASA has to keep in secret even the date of Shuttle lifts. How they are going to protect the system functioning 24/7 in a place surrounded by see?
Any ship with 200 miles missiles can come to 200 miles distance and hit it. They cannot do wider security zone with today's international laws, but if they can (let's say 400 miles then it will be a matter of time to see a ship with 400 miles missiles hitting the target.
I think before such project will be built they have to improve somehow the quality life of international community. USA govt should begin to respect UN. UN should work more actively against potentially aggressive goverments, even against potentially unstable goverments. That may mean a completely different system of international laws than we have now.
So, if the idea to bring the highlift project alive will help to improve the international community - we should do it. Otherwise, it's danger for the current world of aggresive animals.
Less is more !
You might want to take a look at "rotovator" systems, which rely on reaction mass from the ground (or on momentum transfers from rocks in space being lowered to Earth) to keep them in orbit, but which therefore don't need to be tethered to the ground and so don't need to be in a geosynchronous orbit. You spin the entire rotovator in such a way that its tips come to a brief stop in the atmosphere for payloads to be attached, and counterintuitively this allows the rotovator to be much shorter, lighter, and less stressed than a geosynchronous elevator would be. Geosynchronous beanstalks on Earth pretty much require supermaterials like buckytubes; you might be able to pull off a rotovator with Kevlar.
A bit of correction, though:
Your design is slightly different in that you have the CM sitting outside geosynchronous orbit in the realm where it experiences the outward centrifugal force all the time.
Right. This also keeps the system more dynamically stable and allows you to have a base station that isn't exactly on the equator.
So you've got the other end attached to the ground, pulling up on it.
Pulling down on it really, but I think you get what I mean. "Up" and "down" start getting a little fuzzy in this discussion.
This is conceptually a little bit simpler to grasp, but it puts increased tension in the cable,
No, it doesn't. The "increased tension" is only there when a payload isn't. Once you load your payload onto the cable, the payload weight provides the force that had previously come from tension between cable and ground. Since payload weight is a force that even a detached cable like your proposal would need to support, having the same force constantly applied through tension doesn't add anything to the structural requirements of the cable.
and after lifting a certain amount of stuff into orbit, the CM of the system will reach geosynchronous orbit anyway-
No, it won't. The CM of the system will always be above geosynchronous orbit; that's how you keep the system from falling back to Earth. The CM starts out above GEO, moves closer to GEO as you add payload, then moves farther away from GEO again as the payload rises.
and all the tension at the ground will be gone.
If all the tension at the ground is gone, the cable starts to crumple. You don't let that happen.
If the anchor has to be in water anywhere within +/- 45 degrees of the equator, then what's wrong with the Great Lakes? Most of Michgan and Huron, and all of Erie and Ontario are below 45 degrees. There are major airports all over the place, the waves don't get as bad as those at sea, there are no hurricanes, most of the water area is within US terrritory, and equipment can be easily barged in from anywhere along the Eastern Seaboard via the Saint Lawrence. The only negative that I can think of is that the winters are sometimes hard (icing problems?). I vote for Lake Ontario, just north of Rochester. The local economy could use something like this.
...brotha! Simple high school physics.
I don't think this is a feasable way of generating electricity, but not for the reason you stated. Any conductive loop traveling through a magnetic field will generate a current (Assuming the plane of the loop is not parallel with the field). This current is also relatively easy to tap (this is more or less the basis on which all electrical generators operate). The problem is that there is no such thing as a free lunch. It's been a while since I worked in this field, so I may be a little off, but the basic problem is that the current generated creates a magnetic field which opposes the initial magnetic field. This has the effect of turning the loop parallel to the magnetic field thus destroying the current. You could solve this problem by making three mutually perpendicular conducting loops, but even then, the opposing magnitic fields would attract each other, causing your satellite to de-orbit (trading potential energy for electrical energy). The interesting thing I have wondered, however, is could this principle be used to de-orbit obsolete satelites, or more interestingly, could you use it in reverse to boost satellites into higher orbit using electrical power alone. I believe I read somewhere that the useful life of most satellites is determined by how much fuel they can carry for station keeping. Wouldn't it be interesting if the vast majority of that station keeping could be done with solar cells instead of propellant.
The effect of this may be immeasureable, but
wouldn't use after use of the elevator as an
interplanetary launch platform start sapping
rational energy from the Earth.
As we start lifting more mass into orbit and
throwing more mass off the Earth, our rotational
speed drops. Doesn't it?
Longer weekends?? haha
Stay out at the bars later at night?? haha
`Nothing' is probably too general a statement for something as large and flimsy as a solar sail, but I agree in principle.
In that case, I'd be looking for interesting diffraction/refraction/polarisation effects, and also seeing about a secondary sail powered by light reflected from the first.
Got time? Spend some of it coding or testing
Ah, so tens of thousands of years away instead of tens of years away? It makes a slight difference to my enthusiasm for them...
Nanotubes are already up to centimeter sizes and climbing, you'd only need meter-scale fibres for this (they're to be embedded in a composite sandwich for a alignment and cross-connection purposes).
Got time? Spend some of it coding or testing
$17G. I've already had a stab at asking Bill, Larry and Scott, and not seen a reply. It would be most appropriate if Sun funded it. (-:
Got time? Spend some of it coding or testing
If it's entirely unnecessary to the purpose, costs more, and risks circumcising your planet then it's unquestionably over-engineered. (-:
Got time? Spend some of it coding or testing
you modded me flamebait for that??? wtf?? it's a stoopid reply to a troll post... and it's the truth... which is the sad part.
tcpa SUX!!!!
Why is it a requirement?
Got time? Spend some of it coding or testing
Eh, show me an engineering project that's used them. Until then, it's more "magic business beans" (I like the current IBM commercials! They're still the deposed evil empire, but I like the commercials.)
Something as easy as fusion power has remained 20 years away for fifty years now. Until you can buy it or make it, it's a science project, not engineering. (I'd worry about the stability of the composite matrix over time, radiation and stress, but that's just me.)
I'll say it again: we need a new space transportation system within ten years.
Beanstalks are a nice idea, but scaling up from a centimeter to 100,000 KM is a few orders of magnitude, plus other things we might not be aware of yet might cause trouble. (I'm sure that we knew all about bridge building in 1940. Or did we? I doubt tidal resonance would ever be a problem, right?)
One line blog. I hear that they're called Twitters now.
Something like Poe's mystery story about a locked room....I forget the name....
The Muzak did it! Muhahahahaaha!
It's old. The more humans I meet, the more I like my cats. At least they are honest.
Vague knowledge here, but doesn't the coriolis effect have something to do with a planet's rotational momentum and it's atmosphere?
As in, the planet is rotating one way but for what ever reason (low gravity? very very fast rotation?) the gas at the surface of the planet is moving in the other direction.
Wolf, could you please correct me if I'm wrong?
Are you in a classified department at the gov't? They only release bits of the information on the actual specs, and even those are vauge.. We know it's black. We know it's max speed is in excess of Mach 4, and it has a service ceiling of LEO. Search the net a bit, or find a good book on the subject.
M L/ EC95-42883-4.html
:)
:)
As for the term LEO (Low Earth Orbit), a quick search on google found NASA's defination as:
http://lsda.jsc.nasa.gov/kids/L&W/glossary.htm
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Low Earth Orbit (LEO)
LEO is the term used to describe the space between 160 nautical miles to up to 300 nautical miles attitude. Which is the range of Space Shuttle missions.
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The highest number on an official site I've seen for the SR-71 said 50 miles, so the other references of it flying there fall outside of NASA's spec for LEO.
Orbit is definately where you're flying, not that you're actually maintaining it.. Mir was in orbit til it hit the Pacific. It was in anything but a circle.
And don't forget about geosynchronous satellites.. 0 ground speed. If it wasn't, you'd have one hell of a time readjusting your DSS dish constantly. They have no speed to 'em, they just hang on a logical string (gravity).
This page cites the SR-71 to do at least:
http://www.dfrc.nasa.gov/gallery/photo/SR-71/HT
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Developed for the USAF as reconnaissance aircraft more than 30 years ago, SR-71s are still the world's fastest and highest-flying production aircraft. The aircraft can fly at speeds of more than 2,200 miles per hour (Mach 3+ or more than three times the speed of sound) and at altitudes of over 85,000 feet.
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16 miles, or Mach 3.14 (at sea level).. But since it's still classified, they're just giving minimum's..
Kind of like saying my car can do 65mph, even though I know I've driven it over 160mph. General Motors can't advertise that the TransAm WS/6 or Camaro SS can do in excess of 160mph, so they just say "Fast".
BTW, a standard late model TransAm can exceed 150, without trying hard, you just need lots of road to do it in.. At 2.5 miles per minute, a couple seconds covers lots of ground. A WS/6 gets there even faster. Trust me.
Serious? Seriousness is well above my pay grade.