Report: Space Elevators Are Feasible 374
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."
Arthur C. Clarke introduced me to space elevators (Score:5, Informative)
It's a very well-written novel that focuses on many of the technical aspects of building a space elevator.
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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.
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"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.
Re:Arthur C. Clarke introduced me to space elevato (Score:5, Informative)
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Re:Arthur C. Clarke introduced me to space elevato (Score:5, Funny)
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.
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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.
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And thus another duplicate ID is outed.
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Read the study? I'm impressed when someone here takes the time to read the summary!
Re: Arthur C. Clarke introduced me to space elevat (Score:2)
Re:Arthur C. Clarke introduced me to space elevato (Score:5, Informative)
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
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Up mod parent:
http://www.virginiaedition.com/media/spaceelevators.pdf [virginiaedition.com]
Re:Arthur C. Clarke introduced me to space elevato (Score:5, Informative)
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.
Laughable what? (Score:5, Insightful)
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?
"Feasible" doesn't necessarily mean "Advisable". (Score:5, Insightful)
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.
Spoiler for "Red Mars" by Kim Stanley Robinson (Score:3)
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.
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That is a (one of several, but in my opinion one of the more regrettable) unfortunate failure to do his homework, frankly. The cable he envisioned was hard, durable, dense stuff. That's not what you want, though. The only real criterion is tensile strength, and density is actually the exact opposite of a desirable property. Dense materials (I believe his cable used diamonds, which are notable for hardness more than for tensile strength) simply increase the tension the cable is under, making it harder yet to
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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.
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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
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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.
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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
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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 safe
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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.
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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 f
weight of elevator is pulling up, not pushing down (Score:4, Interesting)
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'.
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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...
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Re:"Feasible" doesn't necessarily mean "Advisable" (Score:4, Informative)
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?
Before you lecture others (Score:2)
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"
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Then you have a different nightmare
People who live within a few hundred kilometres had better not be scared of spiders.
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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.
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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 w
It's just a background special effect (Score:2)
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 too
The worst part of that trilogy, IMO (Score:3)
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 o
The Tall Tower (Score:2)
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 [asu.edu]
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.
Predictions (Score:2)
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.
Radiation shielding not feasible (Score:4, Informative)
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.
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Even with todays technology
Luckily, by the time we're really ready to build a space elevator, we'll be using tomorrow's technology [bbc.co.uk].
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Why would the elevator be limited to ~200m/s?
Once it is out of the atmosphere, there is no drag and over the distance to the Van Allen belt a 1 G acceleration would bring it up to very high speed. There would be plenty of time after leaving the Van Allen belt to slow back down, again with mild acceleration.
What is it that I'm not seeing here? Would we not use some form of railgun technology to accelerate and decelerate the capsules? We might need a transfer platform above the atmosphere to change from a "
Re:Radiation shielding not feasible (Score:4, Informative)
Simple solution for the Van Allen belts: remove them.
https://en.wikipedia.org/wiki/... [wikipedia.org]
High Voltage Orbiting Long Tether, or HiVOLT, is a concept proposed by Russian physicist V.V. Danilov and further refined by Robert P. Hoyt and Robert L. Forward for draining and removing the radiation fields of the Van Allen radiation belts[29] that surround the Earth.[30] A proposed configuration consists of a system of five 100 km long conducting tethers deployed from satellites, and charged to a large voltage. This would cause charged particles that encounter the tethers to have their pitch angle changed, thus over time dissolving the Van Allen belts. Hoyt and Forward's company, Tethers Unlimited, performed a preliminary analysis simulation, and produced a chart depicting a theoretical radiation flux reduction,[31] to less than 1% of current levels within two months[32] using the HiVOLT System.
If you're going to be building a space elevator, getting rid of the Van Allen belts is a relatively easy task in comparison.
Single point of failure (Score:2)
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.
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Sigh... your numbers are wrong, your science is wrong, and your concept is questionable.
Let's start with the basics: GEO is 35,768 KM from the equator. You need twice that much, at most, ribbon (not cable. Cable is dramatically less feasible and stupid besides). No idea where you got 100,000 KM from...
Now, about that ribbon. It's a few feet (maybe around one meter) wide at the base, where tension is low. It's several times that at GEO, where tension is highest. It's got a thickness comparable to paper and a
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You post is mostly wrong and stupid.
". It's got a thickness comparable to paper"
What do you base that one? It has to be able to carry an elevator, you know for the space elevator
" will mostly burn up in the atmosphere"
Do you even have a clue what cause things to burn up in the atmosphere?
Why do you ignore the fact that the counter weight is going to fly off, do a figure eight, and the come back to earth?
When something strike the counter weight, it' will have a different angle of momentum and push it out of
Sounds like a great idea (Score:5, Funny)
Re:Why would it be infeasable? (Score:5, Funny)
Yeah, the plastic they use for retail packaging should be strong enough.
Re:Why would it be infeasable? (Score:4, Funny)
Problem is that plastic's extremely porous and fragile until it gets to its actual destination. And since the Elevator is effectively always in transit....
I believe the plastic in question is the kind of plastic that semi-permanently entombs your purchase in a chrysalis so touch that you need a diamond tipped super electro buzzsaw or a weapons grade baloneyum industrial laser to burn through it.
BestBuy packaging - toughest stuff known to man.
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I believe the plastic in question is the kind of plastic that semi-permanently entombs your purchase in a chrysalis so touch that you need a diamond tipped super electro buzzsaw or a weapons grade baloneyum industrial laser to burn through it.
I bought one of those, but I can't open the package it's in.
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True story. A coworker bought a scissors and couldn't get it open without a scissors, but there wasn't a scissors in the office which is why he bought one.
Scissors is an interesting word. Apparently derived from the latin word for chisel => a pair of chisels.
Wikipedia [wikipedia.org]:
The noun "scissors" is treated as a plural noun, and therefore takes a plural verb ("these scissors are"). Alternatively, it is also referred to as "a pair of scissors". In American English, "a pair" is singular and therefore takes a singular verb ("this pair of scissors is"). In British English, "a pair" does not take the singular ("this pair of scissors are"). The word shears is used to describe similar instruments that are larger in size and for heavier cutting. Opinions vary geographically as to the size at which 'scissors' become 'shears', but this is often at between six to eight inches (about 15 to 20 cm) in length.
And yet, Wiktionary [wiktionary.org] says
(countable, plural in form, usually with a plural verb) A tool used for cutting thin material, consisting of two crossing blades attached at a pivot point in such a way that the blades slide across each other when the handles are closed.
Those scissors are sharp. (indicating singular or plural scissors)
That scissors is sharp. (less commonly to indicate singular scissors)
Scissors are used to cut the flowers.
Use a scissors to cut them if you don't have proper shears.
Re: Why would it be infeasable? (Score:5, Interesting)
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My kingdom for mod points. This is sad but true. If we do ever leave it will be to mine unobtanium like in the movie Avatar, not to further mankind in general.
Picard tries to explain to Ralph Offenhouse from the 20th century that there would be no need for his law firm any longer: "A lot has changed in three hundred years. People are no longer obsessed with the accumulation of 'things'. We have eliminated hunger, want, the need for possessions." (TNG: "The Neutral Zone") - http://en.memory-alpha.org/wik... [memory-alpha.org]
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I'm not sure Star Trek should be considered in the same sentence as talk of viable space exploration the future.
Utopian thinking is nice but it's an ideal not a potential reality.
Re: Why would it be infeasable? (Score:5, Interesting)
Financial gain may be the most likely reason for advancement now, but it won't take more than another 50 to 100 years for it to become a necessity due to any combination of pollution, population, warfare, and resource depletion. Humans have always been really crappy at innovating unless we absolutely have to. When we aren't faced with some kind of crisis, we tend to get really good at perfecting known technologies and ideas, but that's about it.
So yeah, space exploration is pretty much out of the question as long as people (both investors and consumers) are more interested in mobile phone games and reality TV. As soon as shit hits the fan again -- and it will -- we'll see another big leap in advancement.
Re: Why would it be infeasable? (Score:4, Insightful)
what it'll take it for China to start weaponising space, "for their own defence" and then funding will immediately be made available to get other countries weapons system up there.
Why else did the US go to the Moon - it was because there was a chance the Russians might have found a way to put missiles on there of course, all dressed up as exploration and "good of mankind".
So c'mon China - we're bored of terrorists, we need a new 'enemy' to spend vast sums defending against! you guys are the only ones with enough cash to do anything.
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Don't worry, China is willing to take risks and try unorthodox ideas to defend themselves against the US, which spends utterly insane amounts on weapons.
The super-rich are just paying to be first ... (Score:3)
That said, I do not believe th
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"Now I see it as the fantasy it is, because without some compelling financial gain in taking trips up there for anything besides tourism for the super-rich, I think we are going to stay stuck on this rock."
What a silly thing to say.
There are already real commercial proposals to mine the moon. There are also private, commercial proposals to mine asteroids. Sure, neither one will happen tomorrow but the important thing is that it's beginning to look feasible.
Further, just because Obama is myopic and wants to ignore the moon, that doesn't mean other nations are. Which is just yet another strike against him. Get a President with a head on his shoulders in office, and maybe we'll be back there within a few y
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And the desire of anyone with the ability or funds to do it to go to space regularly enough to need it.
It's like proposing to the East India Company to build a modern mammoth tanker. They would not understand why anyone would want to transport such quantities of material across the ocean. You can't really blame people for not having a clear vision of the future though.
When I think back to being a kid and how space felt like the future, it makes me sad that typically it seems like no one besides researchers gives a shit anymore. I used to watch Star Trek and knew it wouldn't happen in my lifetime but it felt like that was the eventual goal and the direction we were heading in. Now I see it as the fantasy it is, because without some compelling financial gain in taking trips up there for anything besides tourism for the super-rich, I think we are going to stay stuck on this rock.
I disagree.
Firstly, we have some exciting missions to planetoids. Pluto and Ceres are about to be visited (spacecraft is already on its way).
Secondly, the ISS is a great success of global cooperation. And now it is being supplied by commercial
Money, politics - tech is the least problem (Score:3)
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, mea
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If you're going to build a space elevator an anchored/oil rig like floating platform isn't much of a stretch.
Re:Money, politics - tech is the least problem (Score:4, Insightful)
No more imperial powers? Seriously? You know where the European Space Agency launches their rockets from? French Guiana, which is a French territory in South America. Then of course there's the 800 lb gorilla. The US has actual territories around much of the world, from the Atlantic to the western Pacific, occupied or controlled countries around the rest, and military bases pretty much everywhere.
If a major nation wants to have an equatorial space elevator base they'll pick an appropriate country, throw some money at them, and get it.
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Or construction workers (somebody had to build those spaceships and space stations, after all). Or traders/merchants/shippers/etc. since interstellar, much less interplanetary, commerce was very much a thing that people were doing. Or technicians, to keep that infrastructure running. Or colonists, off to settle other worlds. Or emigrants, moving to one of those colonies after the initial settlement. Or tourists, heading to Risa (or any of the other pleasant parts of the galaxy reachable by warp drive). Or a
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Re:Flying pigs (Score:5, Interesting)
As bigjarom mentioned, what's holding us back right now from cheap lift via skyhook is that we haven't quite gotten our carbon nanotube strength up high enough. It's theoretically quite possible.
After that, it's just a question of how do we get enough materials and probably some sort of ribbon* making facility into GEO to actually do the laying. One idea I have is that rather than having to ship all materials to GEO, only to drop it towards the earth, you have a descending constructor that you supply. Though the orbital mechanics of resupplying it can get quite hairy...
*Modern design philosophies has the cable being more of a flat ribbon than circular.
Re:Flying pigs (Score:5, Informative)
Comment removed (Score:5, Insightful)
Re:Flying pigs (Score:4, Interesting)
Perhaps it hasn't been addressed much, but from what I've seen part of the 'protection' is that you would be more or less continously extruding new cable(on the order of a couple miles a day!), so as time goes by the cable WOULD be refreshed.
Besides that, if you're sensible you're going to orient your ribbon so it's the narrow end that's facing most probable impacts, highly limiting it's cross section. Then you have to factor in that this material will be the strongest material used in space to date; it should be quite resistant to those effects.
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Actually in a design I saw some time ago, the cross section of the ribbon would be more like an arc of a circle. No straight line path of a micrometeorite would be capable of severing the cable.
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Then you have to factor in that this material will be the strongest material used in space to date; it should be quite resistant to those effects.
I don't have the numbers handy, but I'm thinking the ribbon material is a couple orders of magnitude at best stronger than conventional materials, while impact energy is MANY orders of magnitude higher than the "strength" in question.
To put it another way, if an impact dumps enough energy to raise several cubic millimeters of material to a five-figure Kelvin temperature, the "material strength" becomes somewhat irrelevant. Vapor/plasma doesn't resist tension very well.
In fact, I'd think that stronger materials would receive more transferred energy from an impactor as it's punching through. You'd just have to count on having enough material left to hold things together.
Correct.
Stronger materials are worse in structure impact scenarios because they transfer nearly all of the energy to the structure. You need flexible materials, a non-rigid design, and break-away failure modes. This all then necessitates a very redundant (and thus large) structure. If your carbon nanotube cable/ribbon takes a high-energy impact, the issue isn't the entire cable/ribbon surviving, it's preventing the energy from transferring to the structure (the anchors and the payload).
I say build it wit
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Then read the study [virginiaedition.com]
They address micro-meteorites, lightning, induced currents, radiation exposure, and a whole host of other objections. The biggest problem they identify is the obvious one. We don't have any materials to build the tether with yet.
They "project" that such materials will become available in the 2020's, which is good....that's a whole 14 years before nuclear fusion!
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how do we get enough materials and probably some sort of ribbon* making facility into GEO to actually do the laying.
There's no way this will get built with materials launched from Earth, it will have to use resources mined in space. Just the segment from terra to GEO will have to be 23 thousand miles long; even just for a single "strand" we don't have a vehicle that can lift anywhere close to that much material. Lifting all the "strands" necessary would take many thousands of launches.
OTOH, once SpaceX gets its reusable boosters working, [slashdot.org] it will be much cheaper to get up there. That will speed up the development of space
Over-estimating weight (Score:3)
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. [thespacereview.com] Another says 20 [wikipedia.org].
A Falcon Heavy [spacex.com] 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.
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they have a young scientist named Peter Parker working on it.
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speed of light (Score:4, Interesting)
Speed of Light: 299,792,458 m/s (meters per second)
Great Pyramid Grand Gallery: 29.9792458N Latitude
coincidence?
Re: speed of light (Score:3)
Of course it's a coincidence.
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Which is really too bad. I was looking forward to seeing how they would handle the problem of harmonic resonance in the cable, and wind blowing the cable, and cable breakage (which would be a matter of when, not if), and what technique they were proposing to get the cable up there in the first place.
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--I would love to see a space elevator happen in my lifetime, but I'm also concerned about terroristic threats. All it takes is a few maniacs to decide they're willing to fly some planes into the cable, or bombing the base of it. Vidgame Halo 3 had a few scenes where the space cable had come down after a Covenant attack and debris was lying all over the landscape for miles. What kinds of safeguards do you put in place for contingencies?
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Its less than the cost of a lousy hamburger (Score:2)
And definitely less than I spend in beer when I go out. Don't be so cheap that you're left behind... Buy it!
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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.
Well to be fair, it says:
This study was conducted under the auspices of the International Academy of Astronautics (IAA) and benefited from review and comments by numerous members of the Academy, as well as the International Space Elevator Consortium.
I've never heard of this IAA, but the wiki page says they have been around since 1960:
http://en.wikipedia.org/wiki/I... [wikipedia.org]
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i say let's get fusion right first, then invest in SETI programs, then make contact with another intelligent force, then see how they approached the space elevator problem. Then we can apply alien civilization best practices to leap-frog the current space elevator timeline.
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We have both people worried about space elevator cables crashing to earth if an airplane hits one and people concerned about SETI not picking up incidental radio leakage from alien civilizations on the same story.
Can I get somebody to please express concern about the LHC creating a black hole on Earth so I can go home for the day?
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We don't even know that much, but we may be getting close.
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A well engineered space elevator would be a new source of power, producing more than it would cost to maintain it. Assuming that some form of mass (captured asteroid, lunar regolith, etc) could be delivered to the geosynch platform.
Regenerative braking on material moving down the elevator would produce power. A particularly elegant system would launch cannisters of regolith from the lunar surface to the geosynch platform with a railgun, then the cannisters are "dropped" down the elevator with regenerative
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Apart from Ecuador or Africa, the equator is mostly ocean
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Ocean, actually. We have rather a lot of it, especially around the equator.
Sigh. This whole "the cable could fall and kill us all!" bullshit has been debunked again and again, but still people keep pulling it out of their asses like they have any idea what the fuck they're talking about. Do at least a little research before spouting your mouth off, OK? For starters, ribbon, not cable. Think silk scarf, not suspension bridge.
Oh, and as for the idea that where you built it would matter for people living "in t
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>>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
Re:Rockets won't be loved at (Score:5, Interesting)
I've seen proposals that talk about using a ribbon that is only just barely larger than is needed to support itself for the initial strand. Send it up in a conventional rocket (at the time this was discussed, they talked about using a Saturn V or possibly even the Space Shuttle; these days a Falcon 9 Heavy would probably be enough or even more-than) to geosync and have it unspool in both directions from there. Grab the lowered end as it reaches earth. Then, send up a small climber, carrying another, possibly even smaller strand of ribbon. Join it to the first one. Now you have a stronger ribbon. Repeat (potentially with increasingly large builder-climbers) until you have a strong enough ribbon for whatever you want to do (send up people, or ISS modules, or other satellites, or parts for a Project Orion-style nuclear pulse rocket to be constructed in space... you get the idea).
I don't know how feasible all the steps there are, but it's worth considering as an alternative to sending up the entire thing all at once.
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A counterweight always seemed kind of silly compared to just extending the ribbon as far in the other direction. That way you can also "build" the elevator by unspooling cable in both directions from GEO. You also get the ability to use the upper portion as a launch platform for interplanetary travel (at the end of the ribbon, you'd be experiencing a strong acceleration *away* from earth, just let go at the right time for the direction you want to travel).
Laser-delivered power is one good option. There are
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Or...
Christians [wikipedia.org]
Jews [wikipedia.org]
Communists [wikipedia.org]
White supremacists [wikipedia.org]
Environmentalists [wikipedia.org]
Neo-luddites [wikipedia.org]
Unionists [wikipedia.org].
And whatever the fuck these guys are [wikipedia.org].