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Report: Space Elevators Are Feasible
Daniel_Stuckey writes "It's the scourge of futurists everywhere: The space elevator can't seem to shake its image as something that's just ridiculous, laughed off as the stuff of sci-fi novels and overactive imaginations. But there are plenty of scientists who take the idea quite seriously, and they're trying to buck that perception. To that end, a diverse group of experts at the behest of the International Academy of Astronautics completed an impressively thorough study this month on whether building a space elevator is doable. Their resulting report, 'Space Elevators: An Assessment of the Technological Feasibility and the Way Forward,' found that, in a nutshell, such a contraption is both totally feasible and a really smart idea. And they laid out a 300-page roadmap detailing how to make it happen."
Flying pigs are also doable.
That does not mean that they are a good idea, or that they are easy to make.
The three laws of thermodynamics:(1) You can't win. (2) You can't break even. (3) You can't even quit.
The main thing stopping us is funding and lack of materials of the right tensile strength.
For anyone interested in the concept of the space elevator, The Fountains of Paradise (1979 Novel) by Arthur C. Clarke, is a must-read!
It's a very well-written novel that focuses on many of the technical aspects of building a space elevator.
"It will happen - probably about 50 years after everybody quits laughing"
Perhaps it is true that "plenty of scientists take the idea seriously" - but the summary links to a book commissioned by the International Space Elevator Consortium.
I am Audience.
How else are you to land and/or launch from a new planet/moon? We still need rockets. Unless stargate
The elevators in my building are slow and get stuck once a week. I can just imagine getting stuck on the 1,200 floor. No thanks.
It's the scourge of futurists everywhere: The space elevator can't seem to shake its image as something that's just ridiculous, laughed off as the stuff of sci-fi novels and overactive imaginations.
I've first heard of space elevators decades ago, and not once have I read or heard anyone saying it's a ridiculous or laughable idea. All I've heard is that it'd be a really great, smart and economical way to access space, if only a strong and light material could be found to prevent the cable from being several miles across in diameter at the base and collapse under its own weight. Where did the story's submitter get that from?
"A door is what a dog is perpetually on the wrong side of" - Ogden Nash
One of the things I don't see discussed much is the potential failure modes for such a system.
My wife is a physical oceanographer, and one of the failure modes for instruments deployed on cables from a ship is a 'wuzzle' -- a large tangle of steel cable. Given the nature of the stuff, a length of cable that fits nicely in a spool on deck can twist itself into a knot larger than the ship.
So one thing I'd like to know is what are the potential hazards a couple thousand miles of elevator cable falling to the Earth's surface? Could we end up with tangles miles in diameter?
I think a space elevator is a great idea if it's feasible, provided that in the criteria for "feasible" we include being prepared for the conceivable ways the project could fail.
Post may contain irony: discontinue use if experiencing mood swings, nausea or elevated blood pressure.
This basic concept hasn't changed much since Arthur C. Clark's 1979 novel The Fountains of Paradise first popularized the idea of an elevator to spaceâ"though no one took it seriously. Decades later, in 2003, Clarke stated, "The space elevator will be built ten years after they stop laughing ⦠and they have stopped laughing."
If they've stopped laughing, it's only because they stopped paying attention. Otherwise, we're still stuck where we have been for decades - we barely know how to make promising materials at laboratory test quantities, let alone in the kiloton lots that a space elevator will require. Presuming of course that one of the many "promising materials" turns out to actually work, rather than falling by the wayside like so many others. Like fusion power, elevators have been "a decade away, maybe two" for decades.
Or, just read the linked report by a team of ACTUAL scientists instead of a SCIENCE FICTION story written 35 years ago.
You can't, unless you want to pay for it.
"First they came for the slanderers and i said nothing."
Yeah, a whole 10 bucks for the Kindle version.
Sig Battery depleted. Reverting to safe mode.
I assume you are NOT denigrating SCIENCE FICTION, but just to be sure, I will point out that Clarke also wrote about using geosynchronous communication satellites long before anybody had launched one.
Like maybe one of those unexpected asteroids or meteors happening by ... ?
Awesome point. I recall calculating the tensile strength required as a project assignment in mechanical engineering undergrad 20 years ago, but do not recall discussing how to deal with the fallout of failed attempts.
Now just wondering, at a certain point, would the tangle fall up? Presumably the cable is in tension once set up.
http://xkcd.com/697/
In the above book, a Martian space elevator fails (more specifically, is induced to fail by the deliberate application of high explosives.) The result is highly destructive. The Martian equator is no longer an imaginary line, but rather a prominent physical feature.
Quattuor res in hoc mundo sanctae sunt: libri, liberi, libertas et liberalitas.
Have you read it? Let me know if it's any good. To me, it just looks like a scam to get people's money.
"First they came for the slanderers and i said nothing."
If the break is below the half-way point it will go up if the break is above the half-way point it would come down.
Also the process that seems to most likely for construction would be to deploy from the mid point of the cable and then spool in both directions at once. This way the overall forces remain in balance.
Also everything I have read about planned space elevators has it based in the middle of an ocean. This allows some movement if necessary to avoid something large in space but also gives some safety in the event of a failure. If the cable broke below the mid point controlled explosions all the way along the cable would reduce most of the damage with the a large % of the resultant bits burning up in the atmosphere or landing in the ocean. It would probably be much worse for things in orbit than things on the ground.
Taking space elevators to their logical conclusion though would see them being the bases of super towers that reach into space. The cables end up being the foundation supports of the tower.
You are confusing a space elevator with BitCoin.
Or, just read the linked report by a team of ACTUAL scientists instead of a SCIENCE FICTION story written 35 years ago BY AN ACTUAL SCIENTIST.
FTFY.
I see land prices fall for people living under that cable fall direction..... demonstrations on horizon, or they could build it far in the desert
Clarke had 256 pages and apparently conveyed the general ideas. Paying for 300 pages seems like a stupid thing to do if you want a general idea.
If they cannot communicate how it is feasible in an elevator speech, I don't expect to learn much in the manifesto.
3 pages has sufficed to explain the Higgs (excluding cartoons); I expect to understand the space elevator, in big boy words, in 2 or less. Anything else is hiding something, or so poorly written it cannot be trusted.
Superfluous vocabulary is ostensibly a plausible alternative, however a great many potential readers may find themselves sidetracked by such unnecessary verbosity. As such, I have expectations of a concise manner of thought conveyance as would be warranted by the writers. Vis a vis- said writer probabilistically desires their audience foremost not fall immediately into slumber.
Make a so called "elevator", that's actually a super powered magnetic slingshot, and swing spacecraft into orbit with it... At least you won't have to deal with the structure failing... just the extreme Gs the passengers will be subjected to.
I believe everything below the break point will fall to the ground and also in a path that wraps around the earth. Everything above will go up and stop at a new higher equilibrium point, still straight and under tension.
Really? I was always under the assumption that space elevators were considered a good design and that we were just waiting for materials to present themselves that would be ideal for the conditions.
Well you might also remember that Clark predicted FTL drive in your rush to find a pedestal tall enough.
And maybe you should actually READ the study before dismissing it because it has too many big words.?
Oh, wait, this is Slashdot, we don't do that, do we.
Sig Battery depleted. Reverting to safe mode.
Connected to a platform in space, the mass of the platform is to spin with the Earth's rotation. Centrifugal force is actually pulling on the elevator 'cable'.
$5 / month hosted VPS on linux = awesome!
Neal Stephenson and Keith Hjelmstad who is at Arizona State University have looked into this. The thought is to build a structure that reaches the stratosphere and then launch rockets from the top.
The Tall Tower
I have no idea if this is easier or harder then a fulls space elevator. I would guess not as hard. Sadly, the web site has little activity since I firsrt saw it. Still, it's interesting in the context of a space elevator.
Why is Snark Required?
upper atmosphere elevator
I get the impression that you don't quite understand how a space elevator would work.
I don't think these elevators would operate like a normal elevator, where you have cables pulling a structure up, so you wouldn't have to worry about a spool of anything getting tangled. Most designs have the structure actually "crawling" up the cable.
Given the nature of the stuff, a length of cable that fits nicely in a spool on deck can twist itself into a knot larger than the ship.
lol that's kind of hilarious
"First they came for the slanderers and i said nothing."
The super-rich are not the only potential market, people of modest means engage in tourism as well. All the super-rich are doing is helping to pay for the necessary r&d and initial infrastructure. Costs will come down with improved technology and greater experience. Even **IF** tourism was the only potential space industry there would still be a potential market of millions of travelers. Its just a matter of time as costs work their way down the willingness-to-pay curve.
That said, I do not believe the commercial utility of space is limited to tourism. And whether we are dealing with tourism, scientific research or industrial application there will be a point where getting the resources locally will make more economic sense than lifting the resources from earth. That will open up even more commercialization of space.
All it will take is 1 guy with an RPG and it's game over.
Falling to Earth? Why would it? The elevator itself is in geosynchronous orbit. It won't fall like a tree, or fly away like a kid's balloon. Severing it close to Earth might make a few miles deorbit due to air resistance, but you'd have to read something on space elevators for more details. Literally anything, this question is raised in every discussion I've seen about space elevators because it's the first question most people ask, and I'm certain the linked report discusses this scenerio ad nauseum.
Have you read it? Let me know if it's any good. To me, it just looks like a scam to get people's money.
No money involved, they give it away for free if you know where to look:
http://www.virginiaedition.com/media/spaceelevators.pdf
Archived here:
http://www8.zippyshare.com/v/72888832/file.html
http://www.sendspace.com/file/16c8xj
http://wikisend.com/download/118300/spaceelevators.pdf
Well fuck... we ran out of cable to finish the job
Nanomaterials are strong and light enough, but the rub is that scientists can't get them to scale yet. Luckily, billions of dollars are being poured into this area of research. The report predictsa suitable material will be ready by the 2020s.
Materials are the sticking point and they can predict anything they want. Will those predictions come true? We will only know if and when it happens. I think it is doubtful. From what I can find they have made carbon nano tubes about 130cm long. Extending them to 62,000 miles might not be possible.
Saying something is feasible based on prediction of scientific progress is dubious at best.
If engineered correctly, the total force applied at ground level could be "up" rather then "down".
I almost feel bad whooshing someone with a 5 digit ID. Almost.
The concept is to hang the cable from space, not build up.
Length: 100,000km, anchored on the Earth with a large mass floating in the ocean and a large counterweight at the top end, called an Apex Anchor.
Width: One meter
Design: Woven with multiple strands to absorb localized damage and curved to ensure edge-on small size hits do not sever the tether.
External Power: The power must be external as the gravity well is extreme and lifting your own power is a non-starter.
Dr. Edwards’ approach was to use large lasers pointing up to the climber with a “solar panel like” receiver on its nadir position.
Cargo: The first few years will enable 20ton payloads without humans [radiation tolerance an issue for the two week trip] with five concurrent payloads on the tether for the two-week trip to GEO. [Currently, the plan is seven concurrent payloads for one-week travel.]
What could possibly go right?
Cryonics - Keep cool and carry on.
Read Red Mars by Kim Stanley Robinson.
He describes a scenario in great detail where a space elevator (on Mars, natch) is sabotaged and it falls to the ground. Because of the length of the cable, it winds its way around the planet several times; at first, quite slowly; by the time the end of the cable hits the ground, it's falling at greater than the speed of sound, and causes an impact crater that completely destroys the cable and anything underneath, a kilometres-wide path of destruction around the planet's equator.
It was an amazing passage to read.
http://en.wikipedia.org/wiki/Tower_of_Babel
"You can't, unless you want to pay for it."
And quite a bit. Around $30 is a lot for a "report".
Makes me think this is yet another attempt to sneak in an ad disguised as a discussion piece. We've been seeing an awful lot of those lately.
Yeah, if you want a materials strength nightmare, forget about the elevator cable.
Think about a foundation strong enough to withstand the pressures of a 100-200 mile high tower pressing down.
Why don't you think about familiarizing yourself with the concepts behind the space elevator? There won't be anything like that. The end of the cable "floats" in the receptacle. It hangs from its anchor asteroid.
Oh wait! Lemme get my unobtainium!
Why don't you instead get a quick education in the topic we're discussing before you flap your yap?
"You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
In a novel by Frederik Pohl, one of the heechee series, terrorists set off a bomb at the ground terminal of a space elevator and it causes the rope to fall to the ground.
I think you wooshed by the prerequisite.
Someone found a free copy of the report. Enjoy.
"First they came for the slanderers and i said nothing."
Here's a link to the actual report, so enjoy.
"First they came for the slanderers and i said nothing."
Falling to Earth? Why would it?
Because the cable would break as a result of fatigue from the massive strains placed on it. Seriously, we're talking about a 22,000 mile cable where a single fault could cause the whole thing to come crashing down.
"First they came for the slanderers and i said nothing."
And thus another duplicate ID is outed.
Sig Battery depleted. Reverting to safe mode.
Using the elevator for transfer of goods - will work but the goods will get a huge dose of radiation
Using it for transfer of organic matter (i.e. humans) above LEO is not feasible due to the speed/shielding needed
The worst part of Van Allen belt is about 19000km wide and starts at around 7000km high. Apollo moon missions passed trough it at roughly 15km/s, spending roughly 2*21 minutes in it.
The astronauts received roughly 1rem of radiation through 3 layers of thick aluminum radiation shielding.
That is 1/5 of the yearly the limit in US for people working with radiation.
At reasonable speed (~200m/s) the elevator would take ~26h to pass through the belt, meaning it would need at least 75x more radiation shielding than Apollo did and that the lift would need 15m thick aluminum honeycomb walls (using 70's technology).
Even with todays technology the shielding will be way too bulky/heavy for elevators to be viable alternative to rockets for above LEO human transfer.
>>You loons haven't even built an upper atmosphere elevator
Right, because an "upper atmosphere elevator" is completely infeasible. A space elevator would have to be taken into space in pieces, constructed there, and the cables rolled "down" to earth from an anchor point a hundred thousand miles out. The science behind it is perfectly sound - unfortunately we lack the material necessary for the "cables", at least in any manufacturable form.
But an "upper atmosphere elevator"? The science behind that is not sound. Besides making a pyramid with a base of 10,000 square miles, there's no way to stabilize a structure at that height without something anchoring it in place from the space end.. you'd need... a space elevator to do that. :p
"The true measure of a person is how they act when they know they won't get caught." - DSRilk
Arthur C. Clarke was actually a scientist who wrote science fiction. The actual bulk of his work was science education.
Probably because it's best modelled as a lot of little chunks each with different gravitational force on them and forces from the elements above and below - and that's not trivial if the thing has a break in it somewhere.
The simplest mode of failure is if the thing is under a huge amount of tension and somebody cuts it off at the base - as in at least one movie. In that case the entire thing flies off into a high orbit (for the counterweight, trailing the ribbon behind it) or escapes entirely. Having a huge amount of tension make sense in keeping it straight, but of course constraints of reality would get in the way if we finally have a real material that comes close to having the right properties for an Earth based space elevator.
Not so simple. Gravity varies with distance along the length of the beanstalk. Also whether it snaps in two unequal lengths or fragments depends on a few things. Being designed to fragment and burn up (like your suggestion) sounds like a good idea, and it's likely without explosives since there's not likely to be any room for overdesign. Large stresses from other then the direction it's designed to take it are going to rip things apart if it's something like carbon nanotubes.
Easy - you have it pulling up. :)
Then you have a different nightmare
People who live within a few hundred kilometres had better not be scared of spiders.
A robust system should not totally break because of one point of failure. A single elevator is fragile because any natural (meteorite), man-made (space junk) or intentional (war) cause acting anywhere along the 100'000 km long cable can totally destroy it with dramatic consequences on Earth when parts of the cable impact the surface. The elevator design could be made more resistant by building a network of cables, not a single cable.
the desire of anyone with the ability or funds to do it to go to space
Not only the desire to go, but some destinations ("space" is not a place) are necessary, too. I would expect that the main use of this device would be for freight, not people. For a start the safety requirements are much less stringent (apart from if it collapses on top of people) and therefore the implementation costs would be less.
There's also the little matter of geography. A space elevator would have to be built on or near to the equator. At present none of the equatorial countries have the will, means or need to build one. In the past the imperial powers have created global infrastructure, but there are no more imperial powers and there is not sufficient political stability for others to want to risk 10's or 100's of trillions of <insert name of preferred currency here> in some tropical location outside of their control.
politicians are like babies' nappies: they should both be changed regularly and for the same reasons
Sadly, my slow education shows that you need some as well since the material is still currently unobtainable. Not beyond hope but we can't get it now - hence "unobtainable"
That's overload. Fatigue is lots of little overloads making cracks grow over time.
Also whether it goes down, or up, and then bits of it down later, depends on a lot of things, like how much tension is on the thing. Even if it snaps off at the top end the forces of re-entry are likely to break it up a lot as bits of it decelerate at different speeds and pull on each other. Then will it burn up or stay intact like the graphite crucibles used with molten iron? We don't know enough about the properties of what's likely to be used, apart from the obvious of the minimum strength to weight ratio for it to work at all.
Read the study? I'm impressed when someone here takes the time to read the summary!
Required reading for internet skeptics
And definitely less than I spend in beer when I go out. Don't be so cheap that you're left behind... Buy it!
MSBPodcast.com The opinions expressed here are my own. If you don't like 'em... Think up your own stuff.
If the break is below the half-way point it will go up if the break is above the half-way point it would come down.
Actually, everything below the break falls down, and everything above the break falls up, no matter where the break occurs. The centripetal acceleration is capable of holding the entire mass of the cable plus the weight of all the cars, plus some force to tension the cable. The falling down is also generally not that catastrophic, for the most part, since the max speed of the falling cable will be less than or equal to 50% of terminal velocity for a naked cable due to transverse forces based on the pull from the rest of the falling cable. If you don't assume a naked cable, but a cable with periodic airfoils, the remainder of the cable could be guided to a safe fall shadow.
My problem with that is it assumes infinite strength of the cable and a simplistic 1D model of the forces - HOWEVER THAT DOESN'T MATTER IN THE CONTEXT. It's just a background special effect and not important to a story where any disaster would do and I doubt the author looked into it in as much detail as many on this thread.
I had a long and boring discussion with a bunch of arts students some years ago about that example when they insisted it was what would really happen (which is not a line the author took - just those students) instead of a nice neat fictional disaster to move the plot along. As soon as I started drawing diagrams and mentioned that the pull of gravity will vary over the length of the cable they got very hostile.
A real answer would be more complicated and messy and there would likely be chunks of cable raining down on people's heads over a wide area of the planet for weeks. however that would mean a different and probably far less interesting plot.
Cool! Thanks!
Up mod parent:
http://www.virginiaedition.com/media/spaceelevators.pdf
It was also, sadly, complete bullshit ("sadly" because it's one of the worst research failures in the series, which is otherwise fairly good hard sci-fi). The material he envisioned making the cable out of was not only wildly impractical, it was apparently chosen explicitly because of several characteristics it exhibited that are exactly opposite of what would be desirable. You need a material with an extremely low mass per unit length. You do not need a highly durable material, certainly not on the scale of diamond hardness. You also want a ribbon, not a true cable. That gives the climber more surface area to grip for a given amount of mass per unit length.
The result would be more akin to a silk scarf a few feet wide (at the base, several times that at geosync) and many thousands of miles long slowly falling to earth. Some, possibly much, would be burned up in the atmosphere. Some more would flutter to the ground, buffeted by the winds but no more harmful than if some airplane unspooled a bunch of tissue paper in the high atmosphere and then let it go. Some places it might tangle and fall to the ground in a knot, but even then it would have a fairly low terminal velocity and relatively low mass. You might destroy a building or two in the worst case; you would not wreck the entire circumference of the planet
The very concept of building the ribbon out of anything that could contain the energy needed to produce a "kilometres-wide path of destruction" without harmlessly burning up in the atmosphere is as idiotic as it is unrealistic.
There's no place I could be, since I've found Serenity...
I'm still waiting for scotty to beam me up!
Arthur C Clarke was not what most people would think of as a scientist (a job leading scientific research for a university or company or so forth). Nor did his scientific speculations revolve around applying the scientific method, which is a good description of what a scientist does in a very broad sense.
Slashdot: providing anti-social weirdos a soapbox, since 1997.
Think what you will, accuracy be damned.
Think about a foundation strong enough to withstand the pressures of a 100-200 mile high tower pressing down.
Connected to a platform in space, the mass of the platform is to spin with the Earth's rotation. Centrifugal force is actually pulling on the elevator 'cable'.
Actually, pulling up is much worse than pressing down... The cable would just rip the foundation out from the bedrock. So you'd need to drill really deep to suitably anchor this beast.
Main problem I foresee is what happens when someone presses all the buttons.
which is not surprising, seeing the fact that he invented the geosynchronous orbit in the first place. ;-)
It would be feasible in a world without Islam. As it stands one of those nutters will decide that blowing it up will "sock it to the west", or that reaching for the heavens is some type of blasphemy.
The rest is just details. To the stars, fellow Space Nutters!
Nope, it is pretty easy to balance it in such a way that it will float. This is done by making the end longer/heavier to get it to pull more or shorter/lighter to make it pull less.
Not any less dangerous than a truck on the highway with it's breaks suddenly failing. It's going to splatter any fleshy creature it comes into contact with if it fails, no doubt, but considering the risky activities we engage every day for much less significant rewards, a space elevator has a pretty low risk-to-reward ratio.
You don't know what Clark did.
He researched communications - radio, radar, satellite, developed hardware as an engineer.
http://en.wikipedia.org/wiki/Arthur_C._Clarke
Yet another example of sci-fi authors completely failing to consider the "sci" part of sci-fi. If you bombed the base of a space elevator, the ribbon would fly *in to space*. The bottom is an anchor, holding the ribbon (not "cable" or "rope") to Earth. Ideally it's not under much tension - the high-tension part is the middle bit which sits at geosync, balanced between the pull of gravity and the centrifugal force of the upper segment/counterweight - but it's almost certainly under some (much like a ship's anchor chain, actually). How the fuck would cutting a ship's anchor cause it to sink? That's about the level of stupidity in what you just said.
There's no place I could be, since I've found Serenity...
If they cannot communicate how it is feasible in an elevator speech
Depends on the elevator... a space elevator speech could last hours, if not days. ;-)
XML is like violence. If it doesn't solve your problem, you're not using enough of it. --AC
*SIGH*
Nope! Wrong again.
The ribbon (not cable) is balanced such that at the base point, gravity counteracts centrifugal force, and the tension is near-zero. If the tension is any higher than that, that means the whole ribbon is subject to more tension than it has to be. It also means your counterweight (which is probably just an equal length of ribbon *above* GEO to counteract the length below) is heavier than it has any reason to be, which would make launching the whole thing more difficult.
The base could easily be placed on a barge in the middle of the ocean. In fact, that's just about ideal; it can move around relatively easily, if the ribbon needs to dodge out of the way of something. It's also easier to control access for the sake of security, and may have a handful of political advantages too. Oh, and the base of the ribbon? Kept under tension by means of winches. The ribbon will actually rise and fall a bit, as climbers go up and down it (climbers near the bottom tug the whole thing downward, reducing tension at base to possibly negative unless you take up the slack). That's OK.
There's no place I could be, since I've found Serenity...
The Girl from Ipanema... on a permanent loop...
Space elevators are therefore infeasible.
I get the impression you don't quite understand how materials, physics, engineering, and humor would work. I'm quite well aware of the dozen or so engineering miracles that would be required for your Space Totem to be built, but by all means, do tell.
So, in order to prevent the whole thing from crashing down, there has to be a safety margin of extra ribbon above GEO, meaning some extra tension in the wire, even at ground level. That barge can't be too light-weight, or else it'll turn into a space-barge...
is Oscorp funding this?
If they cannot communicate how it is feasible in an elevator speech....
Ah, but you forget, a space elevator speech is a lot longer ride!
Speed of Light: 299,792,458 m/s (meters per second)
Great Pyramid Grand Gallery: 29.9792458N Latitude
coincidence?
Some drink at the fountain of knowledge. Others just gargle.
Lifting all the "strands" necessary would take many thousands of launches.
Not from what I'm seeing. At least one source says that a 'starter' cable can be had as light as 9 metric tons. Another says 20.
A Falcon Heavy can lift over twice that to orbit, though maybe not all the way to geosync...
After you get the first thread down, you use that thread to lift more mass to increase capacity.
I don't read AC A human right
One of the things I don't see discussed much is the potential failure modes for such a system.
My wife is a physical oceanographer, and one of the failure modes for instruments deployed on cables from a ship is a 'wuzzle' -- a large tangle of steel cable. Given the nature of the stuff, a length of cable that fits nicely in a spool on deck can twist itself into a knot larger than the ship.
So one thing I'd like to know is what are the potential hazards a couple thousand miles of elevator cable falling to the Earth's surface? Could we end up with tangles miles in diameter?
I think a space elevator is a great idea if it's feasible, provided that in the criteria for "feasible" we include being prepared for the conceivable ways the project could fail.
And nobody tends to think of harmonics. Certainly a static cable will be enough of a challenge to build, provided we can discover materials stronger than anything we've ever observed. Add to that the challenges of having a very long suspended string (much like the string of a piano). It will vibrate, and that means undulating with stresses both far above and below the average load. Certainly it could be dampened, but not by traditional means, as there's nothing to push against for dampening at the free end, and no effective bracing near the middle to attach dampening equipment.
Wow. NONE of you actually read the post I replied to.
Taking space elevators to their logical conclusion though would see them being the bases of super towers that reach into space. The cables end up being the foundation supports of the tower.
I was specifically talking about a tower, as opposed to merely a cable-based elevator.
Chas - The one, the only.
THANK GOD!!!
Think about a foundation strong enough to withstand the pressures of a 100-200 mile high tower pressing down.
Connected to a platform in space, the mass of the platform is to spin with the Earth's rotation. Centrifugal force is actually pulling on the elevator 'cable'.
Actually, pulling up is much worse than pressing down... The cable would just rip the foundation out from the bedrock. So you'd need to drill really deep to suitably anchor this beast.
We also have a lot more experience with compressive forces than with tensile forces. The early suspension bridges were plagued with lots of new issues. A space elevator would be no different.
This isn't like building the Chunnel. That was a monumental effort doing something we've done for over a thousand years one more time albeit at a very grand scale. To stretch the analogy, this will be like digging the first tunnel, and odds are excellent that some learning (via mistakes) will occur along the way. If the mistakes are catastrophic, then the learning will come at a very high cost (in lives and dollars).
The cable itself should be relatively neutral to the ground anchor. The centrifugal force countering the effect of gravity to as near a null as possible.
In most scenerios: you have a station in geo-syncronous orbit. It extends a cable in two directions (one towards Earth, one away) such that they counter-balance each other.
Once connected to the anchor, I would imagine you would want some pull (remember: this material is chosen for strength, not rigitdity; it must be under some strain to stay taunt, especially given that you are going to move a mass up and down it), but it's not like the entire mass of the elevator is going to be pulling up on the anchor either... just enough to ensure it doesn't collapse back down to Earth)
You are contradicting yourself. If a single car is sufficient to pull a "balanced" tether out of orbit, then only a similarly small outward force is necessary to counter the force of a car, therefore even a small base-mass (such as a ship or barge) is sufficient to counter that outward force. Ie, if a one tonne car pulling down at 1.5g would pull the tether out of orbit, then you only need a few tonnes outward force (measured at the base) to prevent that. And thus only a few tonnes beyond that to sufficiently anchor the tether down.
Therefore you do not need to "drill really deep into bedrock to suitably anchor this beast".
(In reality, you'd want an outward force a full order of magnitude higher than the cargo capacity. And an anchor-mass another order of magnitude higher than that. So a 1 tonne payload, a ten tonne outward force, a 100 tonne base. Double or triple for reserve. Well within the capability of even a small ship or barge.)
A bigger problem is actually the sidewards torque due to Coriolis as the cars rise and fall. This creates not only additional pull on the cable/ribbon, but specifically bends or crimps the ribbon as the car passes. This will stress the material well beyond the simple linear forces.
Science is all about firing a drunk pig out of a cannon just to see what happens.
I'd like to see a stability analysis on this kind of system. I suppose it would be a nice exercise for the student, so maybe I'll give it a whirl when I've got some downtime.
Clarke also invented the communications satellite. Or, the idea of it.
One day I feel I'm ahead of the wheel / the next it's rolling over me / I can get back on / I can get back on
Like everyone else looking at this, they assume we'll have to use a carbon nanotube tether. They propose a spun tether of nanotubes, but use the strength of individual nanotubes in their model. Nanotube yarn is about 1/10 the strength of the raw material (which is insufficient). Growing the raw material directly would only take a few thousands of years more than the four they plan on using.
You don't actually know anything about Clarke's work, do you?
http://scifi.stackexchange.com...
One day I feel I'm ahead of the wheel / the next it's rolling over me / I can get back on / I can get back on
During a speech he once gave, someone in the audience asked Arthur C. Clarke when the space elevator would become a reality.
"Clarke answered, 'Probably about 50 years after everybody quits laughing,'" related Pearson. "He's got a point. Once you stop dismissing something as unattainable, then you start working on its development. This is exciting!"
Makes sense to me; original link here.
DO NOT GIS that word!
wow.
Those nerds haven't fixed the elevator in their building after seven seasons. You expect them to build one that goes to orbit?
We need to develop extremely high strenght carbon fibers not only for a Space Elevator but for vehicles and such because it's a great way to offset all of the extra carbon being released. Hell if we can use enough of the free carbon, we can cool the earth and gain quite a bit of arable land back from the oceans plus with a quad set of Elevators and a connecting ring, we could move most if not all of our farming to orbit. Lots of possibilities there and I would love to see such before I release my keyboard/mouse from my cold dead hands.
Mod me up/Mod me down: I wont frown as I've no crown
If God had intended man to elevate, he would have given him counterweights.
yeah, building a 13 GT space elevator from carbon nanotubes seems like a great idea -- until the nanites come looking to use the carbon from your body.
the preceding comment is my own and in no way reflects the opinion of the Joint Chiefs of Staff
Their estimated price is $500/kg which is a ridiculous price.
Today a falcon 9 can launch 13150kg to LEO for $50million.
The projected elevator can lift 13150kg to LEO for $6.6million.
A nice improvement until you consider that a reusable falcon 9 launch will cost perhaps $500,000.
Which means Space-X with a little luck can reach $38/kg.
It is not hard to imagine that with modest success at re-usability Space-X can drop the cost from $50million to $5million with just a reusable first stage, which would make the Space-X price $380/kg.
That makes space elevators uneconomical before they are even built.
Now a careful reader will note I am arguing GEO vs LEO prices. Once in LEO a ion engines can be used to make the transition to a higher orbit with all of the same efficiencies of an elevator and they already exist.
I fail to see the economics of a technology with a huge up-front cost and that it looks like a much less expensive investment in rocket technology can devastate.
when it come down? Having something that can wrap around the globed several times may not be such a great idea when it breaks at the anchor point.
The Kruger Dunning explains most post on
Seriously, we're talking about a 22,000 mile cable
No. It's at least double that. A space elevator doesn't just go up to GEO, it's "balanced" at GEO, there's an entire outward arm. (And in reality it would be under tension, so the outer arm would be more massive than the inner, the balance point would be well below GEO.)
where a single fault could cause the whole thing to come crashing down.
No fault could cause the "whole thing to come crashing down". Only the portion below the break could fall. And since it's a known failure mode, you'd have built-in separation points at various lengths. When there's a failure, you release a piece of cable/ribbon at the top and/or bottom ends of sufficient mass to allow the centre section to go into a stable orbit. This allows recovery and repair.
Science is all about firing a drunk pig out of a cannon just to see what happens.
Conversely, you don't know what scientists do, do you?
They don't write down neat ideas in single page essays that get no scientific review. Maybe you could say he was an inventor?
It was a neat idea, but Clarke wasn't the first person to come up with the idea, nor was his short essay widely disseminated, nor did it influence the actual development of geosynchronous orbits.
Slashdot: providing anti-social weirdos a soapbox, since 1997.
Actually there are proposals that take the properties of modern super materials (carbon composites) and calculate the maximum height of a (compression) tower. And, depending on your assumptions, you can actually get above 100km. Even steel towers could theoretically get to 10-15km using modern designs.
There are also designs for rotating orbital tethers which have a tip-velocity equal to the Earth's surface velocity, dipping into the atmosphere to pick up airborne payloads. (Or tower-borne if you combined it with the 100km carbon-tower.) From an engineering and economic standpoint, these are much simpler than a full space elevator, since they require much less strength in the materials, and are built at much shorter lengths.
There are also proposals for neutral buoyancy towers which are... theoretically... possible. (Essentially a series of hydrogen-filled balloon toruses stacked on top of each other, creating a net lift sufficient to hold another tower on top, above the bulk of the atmosphere.)
Science is all about firing a drunk pig out of a cannon just to see what happens.
At one time I believed that the space elevator was the only way we would ever be able to move into space on an economic basis. All rocket based methods were just too expensive. That was until I read what Elon Musk had to say about it http://www.spacex.com/news/201.... The real reason that space exploration is expensive is that we throw away the spacecraft after a single use not the fuel used to get there. Space elevators are very energy efficient and would have great longevity, however, the practical and economic problems of building a 30,000 mile long cable is vastly larger than the problems of solving reusability of spacecraft. SpaceX is well on the way to solving the reusability problem. They have a practical road map and are executing it in spectacular fashion. They have already tested and proven vertical rocket powered landing technology and on their next Space Station resupply mission they will be testing booster landing leg deployment and engine restart to try and achieve a soft splashdown in the ocean. There last attempt of restart was successful however the descent became unstable and they had to abort. It is believed that the landing legs will provide extra aerodynamic stability allowing for a successful soft splashdown. I believe it is only a matter of a few years until they have a fully reusable system. This innovation will drive down the cost of space travel by a factor of 100. In 10 years the average upper middle class American will be able to afford a vacation in space. Travel to Mars will still be expensive but not unattainable for many.
Yeah, if you want a materials strength nightmare, forget about the elevator cable.
Think about a foundation strong enough to withstand the pressures of a 100-200 mile high tower pressing down.
Why don't you think about familiarizing yourself with the concepts behind the space elevator? There won't be anything like that. The end of the cable "floats" in the receptacle. It hangs from its anchor asteroid.
Oh wait! Lemme get my unobtainium!
Why don't you instead get a quick education in the topic we're discussing before you flap your yap?
Regardless of your basic understanding, remember we're ALL discussing a theory and vaporware here, nothing more. Comments from the peanut gallery are unwelcome, especially when the fucking peanut gallery doesn't even know if they're right or wrong. Tread lightly, and wise up.
I feel strongly that the next step to our advancement is to build an artificial ring around the Earth. It would serve multiple purposes: First, build a thin ring - like the thickness of a pipe that extends around the equator of the planet somewhere up in orbit. Then you can make 'nodes' at points around the ring - space stations, satellites, etc - the advantage being that they're held in place by the ring itself. Then you can pave the exterior of the ring with solar panels for the constant generation of power. Then you can drop these space elevators from the nodes. Spacecraft would no longer be designed to have to escape the gravity of the earth - they'd begin their flights from the ring, and you could easily hoist supplies/fuel up to the spacecraft via the space elevators. This could completely revolutionize the way we design and build our spacecraft - spacecraft would stay in space, and never deal with escaping gravity wells. I feel that this would be a significant game changer.
I was wondering how long it would take for the thing to run into one of these:
http://www.wired.com/images_blogs/dangerroom/2009/10/312934main_image_1283-9461.jpg
Actually, unlike a beanstalk, skyhooks are potentially viable using nothing stronger than common carbon-fiber - you really only need a thousand miles or so of cable to make a tumbling skyhook that can transfer you between atmospheric-speed sub-orbital and near-moonshot orbits. Still some serious challenges in making a strong enough cable that can span the US, much less getting it into orbit and keeping it from being destroyed by orbital trash, but theoretically at least it's well within the limits of current technology.
Of course it's not quite as sexy as taking an elevator directly from the surface into orbit, but those Airship-to-orbit folks seem to have solved most of the major issues with surface-to-dark sky airships, which could be the ideal platform for rendezvousing with the (locally) slow-moving tip of a skyhook above any potentially problematic weather. And a tumbling skyhook would be far faster and more energy efficient than either a second-stage airship or any beanstalk climber possible with existing technology.
--- Most topics have many sides worth arguing, allow me to take one opposite you.
So basically they are saying 'a space elevator is possible and a great idea, if only we had a material with high enough strength/weigth ratio'. That's what about everyone already knew 10 or 20 years ago. The only 'news' is that these researches say they expect such a material to be available within 'a reasonable timeframe'.
Unfortunately, it's also highly feasible as a terrorist target. How are you going to patrol the entire span of the cable for kamikazes?
"Love heals scars love left." -- Henry Rollins
The space elevator can't seem to shake its image as something that's just ridiculous
Maybe because it IS ridiculous. It's a cool idea but it is science fiction and will remain so for the foreseeable future.
But there are plenty of scientists who take the idea quite seriously, and they're trying to buck that perception.
Plenty? No there aren't. We do not have the technology to build this and will not have said technology anytime soon. I know someone will say "but carbon nanotubes!" and they are still in the realm of science fiction when it comes to uses like this. Even if we did have the technology, the economic case for it is far from clear. This thing would be hugely expensive, potentially incredibly dangerous (imagine it breaking), requires technology we aren't even close to having, have an uncertain economic payback, be a target for terrorists, etc. Maybe in a few hundred years it will be possible but it isn't going to happen in the lifetime of anyone reading this.
To that end, a diverse group of experts at the behest of the International Academy of Astronautics completed an impressively thorough study this month...
Which you can buy in hardcover for just $29.95. Perhaps if they were really serious about it they might not be trying to sell the report for a profit.
It's a space elevator speech. You'll have plenty of time.
"Molest me not with this pocket calculator stuff."
- Deep Thought
If they cannot communicate how it is feasible in an elevator speech, I don't expect to learn much in the manifesto.
It IS an elevator speech - a SPACE elevator speech - that takes three days to get to the top floor...
unfortunately we lack the material necessary for the "cables", at least in any manufacturable form.
That is just the tip of the iceberg of things we lack. The cables are just the most obvious missing technology. You need things like power, HVAC, orbital debris removal, meteor defense, terrorist defense systems, a base strong enough and heavy enough to hold on to it on both ends, elevator systems, servicing equipment, some way to actually construct the darn thing and equipment to do it, vastly more advanced robotics, and much much more. These things might be more mundane but they are no less important and all of it would have to be developed. Many of the problems are probably solvable but that doesn't make them trivial.
I recall that the aluminum interacted with the incoming cosmic rays and actually made more dangerous secondary particles that were more damaging to the astronauts. http://www.adl.gatech.edu/research/tff/radiation_shield.html
Yeah, because we're totally sure that FTL will never ever ever be possible.
Unity? Screw that: XFCE. Slashdot Beta? Screw that: SoylentNews. Australis? Screw that: Pale Moon. UX developers DIAF
Talk to a physicist.
The point is that Science Fiction authors have to simply assume some things into existence, usually without a lot of explanation or examination of the actual science behind it. They need a hook to allow stuff in their stories that can't be done, either at the time or ever.
That they get lucky sometimes, and something actually comes true is always attributed to huge omniscience and foresight.
Clark was no different. He was just more well read than most. He didn't even invent the concept of a space elevator. A couple of Russians did.
Sig Battery depleted. Reverting to safe mode.
Where did the story's submitter get that from?
Even its biggest proponent acknowledged that some people laugh at the idea. In response to the question "when will the space elevator be built?" Sir Arthur C. Clarke said "about 10 years after everyone stops laughing."
That that is is that that that that is not is not.
Could we end up with tangles miles in diameter?
Maybe, but it would be a very low-density object with lots of surface area. With such a tiny ballistic coefficient, the atmosphere would slow it down to a very low terminal velocity and it would hit the ground (or more likely, the ocean surface) gently.
That that is is that that that that is not is not.
The Space Elevator Will Mean: Less Parking, Weird Ribbon Thing, Constant Loud Whirring Noise, Increased Space Elevator Truck Traffic. Developers have submitted plans to build a massive space elevator in Williamsburg! This monstrosity, completely out of context with existing development in the neighborhood, will be accessible only to the wealthy, forcing thousands of average Williamsburgers from their homes and live-work spaces! Jobs the elevator will generate (operators, repairmen, astronauts) are certain to go to non-residents! Don't sit idly by and let this elevator cast its impossibly long, cold, and very narrow shadow over our homes! CALL 311 AND TELL THEM 'I JUST DON'T NEED THIS SPACE ELEVATOR!'"
Can someone comment on this? I'd like to hear an opinion on whether it's as good an idea as I think it is...
did they come up with some new material while I was sleeping with 10X the theoretical and practical strength to make this possible???
The problem is its not just that super strong material with tensile strength for the 40000 mile long cable, its the shear stength required to have something attach and pull its way up and down the thing day in and day out for years and under the severe space and terestrial environments.
Its like the graphite in epoxy they make high performancce planes and other things out of - you cant have just the high tensile strength grapgite fiber, there has to be the other stuff that stabalizes it against other forces -- a material that windes up weighing much more than the graphite that carries the weight. Same thing for this Space Elevator cable - the materials you wrap around the carbon nanotubes or whatever add to the weight which makes it not able to state together (it cannot hold up its own weight).
This problem is nothing new, so what has changed (if anything) to have someone talk of it again ??
That depends on the science fiction. The classic hard SF writers (like Clarke) tried to outright make things up as little as possible, and then only when necessary. Fountains of Paradise, for example, didn't really make anything up except a material strong enough to make a space elevator out of. As you pointed out, the concept itself was worked out before, and, assuming the materials and some way to get them up there, the concept is sound. Much of hard SF is aimed at considering the implications of the technology that is likely to result from existing science.
Many hard SF writers are actually physicists, engineers or astronomers of some type. Clarke had a degree in physics and mathematics, worked on RADAR during WWII and wrote technical papers for the British Interplanetary Society regarding geostationary telecom satellites (another idea he "assumed into existence" in his books).
Most people don't know what scientists do, including many people who call themselves scientists. People who develop technology are engineers, although that title is claimed in a lot of places to mean someone who can take responsibility for designing and/or building something (like a bridge or a twinkie package). Applied scientist is a weird term that is often used to get around that, but applied science often isn't much like the science you're thinking of.
Clarke did various things typical of an applied scientist or engineer. That's presumably what the OP was thinking of when he said "physicist."
so? in a novel by Alan Dean Foster (credited to George Lucas) people can use a mystic "force" to target missiles into a small port on the surface of a space station, maybe look up the definition of the word "fiction"
Three possibilities, depending on where the break is:
1) cable being flung out into interplanetary space
2) pretty reentry effects and most of the cable burning up
3) somewhere between zero to a dozens of kilometres of lightweight cable falling to the ground.
The magnitude of the Coriolis force depends on how fast you go. The first space elevators will probably be cargo only, with climbers that take weeks to make the trip. We might decide that space elevators simply aren't a good option for people or rapid transport at all. Or maybe the rapid transit cars need to have small lateral rockets to compensate.
That's not engineering, it's wishful thinking. Which is not to say it is *wrong*, just unjustified.
The system is designed to be in static equilibrium, so it is by no means guaranteed that the kind of results you are envisioning are the only possible alternatives.
Post may contain irony: discontinue use if experiencing mood swings, nausea or elevated blood pressure.
FTFY
"They have gun control in Cuba. They have universal health care in Cuba. So why do they want to come here?"-Paul Harvey
Sorry that was what I meant - just put it terribly.
You didn't actually say anything in your post. Do you have another reasonable failure scenario? If so, spit it out and we can talk about it.
He's also the one who first wrote about geostationary satellites. :)
It's easier to be a result of the past, but more fun to be a cause of the future! http://www.spacefinancegroup.com/
In reality, you'd want an outward force a full order of magnitude higher than the cargo capacity.
The number of people talking about the issue of balancing the elevator makes me think perhaps I have misunderstood. I figure I'd probably put a counterweight mass on a climber above geostationary. Geostationary is where things balance, right? The mass above geostationary (at angular velocity of 360 deg / day) wants to fly away, and it holds up the ribbon. Want to put a heavy load on the ribbon bottom? Send a signal to have the counterweight climb further up (which, past geostationary, feels like down to it, right?), increasing the amount it pulls up. Perhaps the distance necessary to apply this effect is substantial, but heck we're already going to geostationary, right?
And from a message further up:
The base could easily be placed on a barge in the middle of the ocean. In fact, that's just about ideal; it can move around relatively easily...
Well, you've basically got a pendulum that is 35,000+ Km long. That's going to be a pretty long period to make it do anything, I bet. Maybe easier would be to just detach it from your barge and roll it up into the sky at the balance point if you need to get out of the way of some terrestrial event.
-- "Oh. This guy again."
I read Arthur C. Clarke's stuff when I was young (and no, this was not last week!). As well as Heinlein, Asimov, PJ Farmer, and many, many others. I was enthralled and entranced. The spirit of exploration has been deep seated within me since those days.
When I read the comments for this topic, I am struck by:
1) The number of people who share my love of exploration, discovery, and maybe a chance to save the species. This number is woefully small.
2) The number of people who have no sense of awe, excitement of discovery, no desire to look past their own immediate universe. people to whom the horizon marks the end of the universe. This is, then as now, too many.
If we (the rest of us) listen to the nay-sayers, we will still be sitting, fighting over the girls and land, on this wore-out world, when the sun goes nova. And that will be sad.
I'm not trying to insult anybody. And my conversation style, grammer and spelling, tend to leave a lot to be desired.
- X/Y -
It's behind a paywall. No, I won't read it before commenting on it. It's not worth the money or time. I presume it says it's possible but not practical, unless done by a government or world consortium. The return is too long and too risky.
Learn to love Alaska
The number of people talking about the issue of balancing the elevator makes me think perhaps I have misunderstood.
Different emphasis depending on what you are trying to explain. The system is almost in balance. The amount of tension at the ground is completely arbitrary. So when discussing payload movement, it's the "almost" that's important. When explaining how the concept works to someone (Chas) who thinks it's a billion-tonne "tower" pressing on the ground, it's the "balance" that's is emphasised to them.
Want to put a heavy load on the ribbon bottom? Send a signal to have the counterweight climb further up
That would work, but IMO if the ribbon is capable of handling the force from the climber+payload, then why not use a base-anchor heavy enough to handle the tension when there isn't a climber? Ie, leave the system in permanent tension.
For early versions (small ribbon, no GEO station), apparently they want to have winches on Earth feed out excess ribbon to increase tension, or pull it back to reduce it. The idea is to keep the tension on the ground-station roughly constant, and fairly light. This is because they assume the first version will be at the very edge of possible, and kept as small and light as possible in order to be able to build it at all. For example, the counterweight would be the rocket-stage and drum from the original deployment. You start in GEO and let out the ribbon, the drum naturally moves outwards to balance the descending arm. [Rather than the usual image of a central deployment at GEO feeding out two arms in balance.]
Re: wobbling versus retracting.
It would also take a long time to winch up and redeploy it each time, during which the the system is useless. Given the number of satellites (especially in LEO) and orbital debris that it would have to dodge out of the way of, it wouldn't spend enough time in operation to justify its existence. During a ship-driven "wobble", otoh, it can still be launching and retrieving climbers.
Science is all about firing a drunk pig out of a cannon just to see what happens.
Comments from the peanut gallery are unwelcome, especially when the fucking peanut gallery doesn't even know if they're right or wrong. Tread lightly, and wise up.
I note that you posted anonymously so that your hypocrisy would not be attached to your name. Why don't you tread lightly, and fuck off?
"You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
How the hell do they propose to keep satellites and whatever other space junk there is from hitting the space "cable"? I've never seen this addressed.
Yeah, that's not helping the perception.
This will never work for 3 main reasons: inadequate tensile strength, inadequate shear strength, differential heat loading causing material; strength inconsistencies, radiation pressure, and finally low natural frequency making it uncontrollable. The gravitational field is a conservative field, meaning there is no free lunch. Just as much energy will be required to life the payload up the ladder as it would be to throw it (rockets are just a fancy way to throw something) into orbit. We haven't even considered friction, drag etc.
In the early 90's (when I worked on the STS program) a bunch of experts convinced the government to spend many millions on a space tether. The space tether was a 3 mile long cable and a coil. The idea was that the motion of the space shuttle through the earth's magnetic field would produce usable electricity in the coil sent back to the shuttle up the 3 mile cable. I was in a meeting when this was mentioned. I said 'that will never work, the cable will snap and they will never even get it deployed. Why? Material non-linearity. I was told to shut up, be a positive team player, etc. I spent all of 60 seconds analyzing the problem. They deployed it, it snapped before getting properly extended and all those millions burned up in the atmosphere as predicted. People got mad at me as if my attitude caused the problem.
Besides all the innumerable other problems with space elevators, at the end of the day they don't actually get you into orbit unless you go right up to the top - a 50,000 km (ish) journey. At 200 Km/h 50,000 km will take 10 days for each trip up and that will also severely limit the elevators total mass capability. Anyway the problem here is that to reach a stable orbit at lower altitudes requires huge sideways speeds, space elevators cant provide any of that sideways motion.
Closely related but even more serious is that due to conservation of momentum the vertical upward translation of a space elevator car creates a negative (backwards) lateral force on the elevator cable. (ribbon string?) This creates at two really big problems. Firstly the sideways force adds extra dynamic tension creating problems for stability with the car and increasing the overall load so requiring a stronger cable. Secondly and more importantly the sideways force pushes the whole structure backwards tending to destabilise its orbit and actually push it out of orbit. - And the great irony here is that the only solution ends up being a rocket attached to the counterweight - one almost equal in power to the rocket that would be needed to deliver the cargo to geosynchronous orbit directly from the ground. No elevators are almost COMPLETELY useless.
As for orbital rings, yes some of the technology looks formidable but they are at least easier than elevators and should have much better ability to deliver heavy cargos to Earth orbit - ie they might actually work. There are plenty of other ideas that are probably even better - like the idea of the Loftstrom loop https://en.wikipedia.org/wiki/... .
However at the end of the day the best solution is simply bigger and better rockets - say using gas core closed cycle nuclear rocket engines. A ship using these could get to orbit with one stage, deliver heavy cargo's then use retro braking to return to Earth - making it fully reusable, far cheaper, far safer, and vastly more capable than current tech. -
https://en.wikipedia.org/wiki/...
https://en.wikipedia.org/wiki/...
When you look at the kinds of rockets needed to get (anything substantial) out to the other planets or to most asteroids anything other than nuclear rockets is simply a joke - getting into Earth orbit is the easy bit.
Below the speed of light Special Relativity is one of the most accurate theories in physics - above the speed of light..
Well, i love the idea of a space elevator.
But....
The fact that the topic autor links a page that does not explain the subject, simply links a "buy this book for $29.95 USD or download for $9.95 USD here" makes me kind of sad..
This was a simple publicity stunt to sell a book.....
In fact, if the autor of the book is trying to make ppl change their view about space elevators it would not be in a 10 USD book that no one will buy, it would be in a public release.
And why no one will buy it??? Because there is something called wikipedia.
Daniel_Stuckey post again when you got something to show that does not involve paying.
And a word to ppl that grade topics on slashdot: This is one of those to put down.