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Space Elevator Update
TheMadReaper writes "The 2005 edition of the Space Exploration Conference in Albuquerque, NM came to a conclusion earlier this week. A large fraction of the conference was devoted to the Space Elevator. Surprisingly, there hasn't been much news coverage of this conference, perhaps because it doesn't have Space Elevator in its name. The most interesting fact I got from the conference is that money is really starting to exist in the space elevator world mainly thanks to the work of Dr. Bradley Edwards at ISR and at Carbon Designs, Inc. The strong nanotube talk was also more promising than last year."
I guess if enough money is pumped into this it will finally get off the ground sooner rather than later.
No, wait. We don't want it to get off the ground do we?
Would be cool to see this in our lifetimes.
So much to do, so little bandwidth.
--
Try Mozilla
Update: Still on ground floor.
What if you happen to get stuck at some weird altitude out of reach of help? If you're stuck high and above, you might have the space shuttle come and rescue you. If you're stuck low, you might have a helicopter come and help you. At other altitudes, you're pretty much fucked.
In the interest of promoting more enlightened discussion, a lot of good information concerning space elevators can be found here.
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~ |rip/\/\aster /\/\onkey
The music in normal elevators is already driving me crazy...
Imagine going upwards for hundred sof miles while having to listen to Julio Iglesias' songs, performed by some guy on a synthesizer. NOOOOOO!
Jeez, try to imagine the havoc if the cable comes loose from its orbital anchor. Thousands of miles of pure splat! Whatever safeguards the builders promise, the NIMBY factor is so huge, it has no chance of happening.
Would somebody explain to me, what happens to this carbon nanotube when lightning strikes it and why it won't "cook" the thing?
A "space elevator" is totally unlike anything ever done before. As I read in a Slashdot post some years ago (referring to nanotubes, the favorite among space-elevator aficionados), "When somebody has built a 40,000 millimeter bridge across a creek on campus, then we can start to talk about a 40,000 kilometer bridge straight up".
The fact that we have not yet achieved one millionth of the task (and in fact fall several orders of magnitude for that) suggests to me that, much as I would love to see a space elevator in place, the job today belongs to materials scientists who are looking at shorter-term goals.
An eye to the future is great, but experimenting on climbers is like practicing the high jump: if you're jumping twice as high today as last year, I wouldn't start drawing any exponential curves. The ribbon is the really, really hard part, and we're currently so far away from it that research energy is better spent elsewhere for a while. 2010 is way, way too close.
Maybe with enough motivation we could get that 40,000 mm bridge by 2010, but somehow I doubt you're going to raise $10 million to build a bridge. The X-prize shot somebody into space for that kind of money.
I'm prepared to be wrong. I'm a software developer, and I've learned that as a consultant I can say, "Your project is doomed" with 95% accuracy before I've even heard your name. Being a nay-sayer is easy. But the real trick is being able to spot the 5% that will actually be profitable, and there are a lot of projects more immediately deserving of this kind of money.
Operating costs estimated at 100 kg/lb, ready in 15 years at most optimistic.
Kilograms per pound? What is that?
Now I know, anything is possible with technology. Science fiction of the 50's is science reality of today. But let's stop the conversation of "is it possible" with that. The question of if the Space Elevator CAN be made seems irrelevant to me.
When it comes to this whole Space Elevator business, the relevant question in my opinion is "would we WANT to make something like that?" To me, it's a novelty idea and nothing more. If people want to get serious about space travel, we need to invest more into the building of in-orbit construction yards (IMHO). Once we get the infrastructure in space to produce the vehicles, we'll find that occasional trips to the "Drydock" from Earth to supply it with raw materials will be far more practical than some 21,700+ mile long elevator reaching into the sky.
-Vendal Thornheart
How about creating a simulator for a space elevator? It would be great to mess around with values to see how possible this thing really is. The closest thing to a simulator I've seen is this but its sadly lacking.
http://spaceelevator.sourceforge.net, anyone?
Ground floor perfumery,
stationery and leather goods,
wigs and haberdashery
kitchenware and food...going up
First floor telephones,
gents ready-made suits,
shirts, socks, ties, hats,
underwear and shoes...going up
Second floor carpets,
travel goods and bedding,
material, soft furnishings,
restaurant and teas. Going down!
It will. Apparently lightning is the worst threat to these things....a limitation that will need to be overcome if this project is actually going to happen.
____
~ |rip/\/\aster /\/\onkey
I've read quite a few posts about "riding the space elevator." I'm under the impression (and yes, I RTFA) that the space elevator would be solely used to send cargo up to space. Astronauts would still get up to the ISS by conventional means, and then the space elevator would just be a cheap[er] way to get supplies up to them without worrying about sending up rockets. Unless I missed something, humans wouldn't be travelling on this space elevator at all.
As long as youre wearing a spacesuit theres no reason why you couldn't base jump off to escape... ...Or for the fainter of heart - atmospheric bungee jumping!
Man what a rush.
------
beware he who would deny you access to information, for in his mind he dreams himself your master
My first thought upon hearing of the space elevator was "what happens if it breaks?" Who cares if science suggests it won't be a catastrophe? Most terrorists do not exactly subscribe to the latest scientific journals. A lightbulb will go off in one of their dim minds and they'll try to ram a plane into the cable, or the tower, or whatever, hoping it will somehow dislodge the asteroid from orbit and send it crashing into Washington D.C. or something. It'd make a great scifi action movie, wouldn't it?
And don't forget it'd be a tremendous icon of Western achievement. You'd better believe everyone in the US, or whatever country eventually builds one, would be proud as hell of it. The media would be going on and on about how it'll usher in a new age for mankind, and so on, and so forth. If terrorists could somehow take it out, wouldn't that have tremendous psychological value? Remember that they chose the World Trade Center and Pentagon to strike at us, two (or three) buildings that symbolized, to them, everything that's wrong with the US. Wouldn't a tower that reaches into the heavens (hello, Tower of Babel?) symbolize that even more?
It's quite reasonable to take terrorism into consideration when designing a structure. While I may be obsessing over the whole "living in fear" deal, its definitely something that needs to be considered.
Forgive my ignorance, MEMS and Nanotech has fascinated me for a while, but I don't know enough of the math behind them to tell if this is true. My grandfather, rest his soul, once told me of something called the Sailor's Rope Rule, which effectively says that the weight a rope can support is diminished by its length. Thus, a 500 lb. rope might support 500 lbs when there's less than a foot or so in length between the pully and the weight, but might only support 250 lbs when there is a good 100 ft. or so... The actual support degradation of course depends upon the width of the rope and the material the rope is made of.
So what I'm wondering is, does the same apply to the weight supported by nanotubes and other molecular chains. I figure it has to be less of a degradation due to the ionic bonds involved, but it would seem to me that, unless some Quantum rule is involved dealing with extremely small-scale weight supporting chains, that they might never overcome this problem due to the sheer thinness of the tubes, chains, etc. It might be extremely strong material, but if it's width is only a few atoms wide, wouldn't this material be, at least in single lengths, more or less useless by the time it got to a respectable length? This is, of course, excluding bundles, which make the most sense, I'm really just curious if the same rule applies to nanotubes as applies to rope.
I recall Arthur Clarke pitching the initial concept for a Space Elevator some time back, and revisited the idea in 3001 : The Final Odyssey - in which he depicted planet Earth having a fully functional ( four actually ) space elevator system; which facilitated a subset of human civilisation living in low earth orbits in reduced gravity - thus invoking presumed benefits of doing so.
Anywho. He spoke a couple years ago, subsequent to 3001's release on how at the time of writing, such a feat was nigh on impossible at this stage - as the materials to construct the 'elevator' were yet to be developed. Until now. The carbon molecule Buckminsterfullerene ( C60 ), also known as 'Fullerene', is supposedly strong enough to actually make such a concept a reality - which is in part the reason the space elevator was hurled back into the limelight of late.
I think its a fascinating idea - which until we develop propulsion systems beyond the primative scope of the 1,000+ year old firecracker concept, certainly seems a more elegant way for the species to venture into Space more regulary. Or, at the very least, be the catalyst for what could perhaps become the initial stepping stones to establishing a permanent presence in space which will hopefully later lead to space initiated launches.
Something I never heared anybody about: Where does the kinetic energy come from that the cargo gains when ascending into orbit? Somehow the cargo needs to gain a huge amount of kinetic energy, because the top of the elevator moves several km/s faster then the bottom. If nothing compensates for this energy, the counter weight would gradually slow down and deorbit, so there must be some kind of propulsion in the counterweight, pushing it prograde whenever cargo ascends and pushing retrograde when cargo descends. Anybody got more info on this?
Before this gets too far, somebody should call NORAD and ask them how many of the 2500+ satellites and other odd bits of junk traveling at 17551mph (LEO) cross the Equator (ascending and descending nodes) and might present a collision hazard. I could be wrong, but shouldn't the answer should be "Almost all of them."
This reminds me of the asteroid/comet problem, the probability of a significant impact might be low, but it only takes one.
A warning label you won't see on the space elevator:
In emergency, USE STAIRS.
Aside from which, manufacturing spacecraft is perhaps one of the most industrially complex things we do. Trying to replicate that in a place more remote, and with far more environmental challenges than, say, Antarctica, would have gargantuan capital costs dwarfing the elevator. In fact, the only way you could probably get the infrastructure up there would be an elevator or something equivalently cheap.
Any sufficiently advanced technology is indistinguishable from a rigged demo
--Andy Finkel (J. Klass?)
This is a space elevator we are talking about. Might as well have the sign say "In case of emergency, use stars."
Don't blame Durga. I voted for Centauri.
Don't worry, once it's struck by lightning once it'll never happen again. So don't hop on the thing until lightning hits it.
A space elevator, or beanstalk, has two big problems for construction: 1) materials that are strong enough, and 2) getting it to stay up.
The first we're getting close to being able to handle. The second is just a matter of having a counterweight that balances the 22,500 miles of cable from the equator (more on that later) to the top. Without the counterweight, the ground end drags it down.
That means that we really need to build this sucker from the middle out: extend equal masses out and in (or up and down, if you prefer) from geosynchronous orbit. That's a very expensive proposition. Whether it's cheaper to ship carbon for nanotubes up or go and fetch some carbonaceous asteroids down to our orbit I'll leave as an exercise for the reader.
A poster above was concerned about the terrorist target of something like this. The one consolation in this one is that you can't build it on US or European soil: it needs to be at the equator. At least one SF author (I forget which) posited an elevator whose ground-level terminus was an upside-down Y to two islands straddling the equator some hundreds of miles apart. Not the silliest thing I've ever read, but I'm not sure it makes much sense. Tethering one end down will be tricky enough.
So it won't be Imperialist America that's building it... but that's not to say it won't have protestors. It'll cast a shadow pretty much across the entire planet. It will likely change weather patterns in the region.
It will create the most valuable real estate in the world.
It's going to end up in some place where technology and resources are accessible: Brazil, Equador, Congo, Somalia, The Maldives, Indonesia, Malaysia, or some Pacific Island are all candidates, my money is on a spot just south of Singapore -- there's enough high-tech industrial nations close enough to justify it there. Brazil is my second guess.
And who knows, maybe we'll find Saddam building WMDs up there. (obligatory Funny whoring)
Design for Use, not Construction!
Given all that, I'd imagine that a terrorist would turn their minds to any one of an infinite number of easier, but still spectacular, available targets. How well guarded are your local dams?
Any sufficiently advanced technology is indistinguishable from a rigged demo
--Andy Finkel (J. Klass?)
Can't we just build a really, really, tall lightning rod next to the 62,000 mile space elevator? :)
Understanding is a three edged sword. - Ambassador Kosh Naranek, Babylon 5
Ground-breaking is right! Mr. Wonka's ingenious solution to base the elevator on a weave of microchocolate fibres is to be applauded. However, once the sun shone on this, the chocolate string melted and the elevator hit like a meteor.
Next time, Mr. Wonka, consider using Oompa-Loompa hair fibers. Or maybe you can beam astronauts into space with that TV ray. Who cares if they come back from their mission 1 inch high?
Don't blame Durga. I voted for Centauri.
Your objections are very leaky.
It is a single point of failure. If any one of the millions of potential problems with a space cable turns out to be a show-stopper, the whole investment is lost.
It's possible to "prove" the space shuttle can't fly based on the number of parts and the failure rate in those parts. Yet it flies. It isn't like we've spent a fraction of the GNP on it. This argument comes down to "I don't think it will work because it seems complicated." It's actually much simpler than riding a bomb into space which is what astronauts currently do.
The benefits are small. The energy needed to shift a payload from the bottom to the top remains the same with or without the structure. The amount of money and energy spent on building the structure needs to be recovered in improved efficiency, and that seems unlikely.
This is just wrong. The benefits are huge! This would reduce cost to orbit by orders of magnitude. When you put material into space, you're not paying for the energy. It actually doesn't take all that much energy to put something into space. The calculation is easy. It's about 60 million Joules per kg (1/2 mv^2 with v=escape velocity). You can take a day to lift (which is 86400 seconds). That gives you about 700 J/s (which is the same as 700 Watts). It's the same energy you need to run 7 100 Watt light bulbs for 24 hours.
All of the investment is up front. There is no incremental benefit to this - the elevator does not become useful until it's complete. Any return on investment (including to governments in the form of kudos or re-election benefit) is delayed until long after completion of the project.
This objection is correct, but trivial. Edwards and Westling, the only ones who have done a realistic design study, put the cost at around $10 billion. That's less than the NASA budget for 1 year. That's much less than building a successor to the shuttle. That's factors of several less than the defunct superconducting supercolidor, and similarly less than the space station. Heck, Bill Gates could in theory build it for fun. Given the international nature of the problem, issues about security, the need for some additional bits of engineering/research, it is a government project. But not an outrageously expensive one.
Professor of Astronomy, Author of Spider Star & Star Dragon (Tor)
It reduces cost to orbit to dollars per kilogram, orders of magnitude down from current costs, and could reliably and regularly put large amounts of material in space. Other benefits include easy and efficient launches to other parts of the solar system, space tourism, etc. Basically, imagine if you could drive to space. That's what this would give the world.
The material being discussed would be more like a ribbon, maybe a centimeter wide, a few molecules thick, rather than a one-dimensional wire.
Professor of Astronomy, Author of Spider Star & Star Dragon (Tor)
Look the longest Nanotube is about 2 mm. (I've seen them and know the student making them.) Nanotube fibers are made but they are tough to do. The amount of MWNT (the easy stuff!) made in the US is small. There is no way to make a massive amount of the stuff. Certainly not the amount needed for an 'elevator'. Now let's consider the minor factoid that you will have to drop something heavier than you are lifting. (Or at least of similar mass.) I have single word that this space elevator project does not consider - physics
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Something that has puzzled me, but I am sure someone has brought up in scientific discussions, is orbital wobble. Will this cause the earth to wobble during orbit? You can take a 5 pound ball, and spin it on a flat surface and observe it, now try taping a .5 lb weight on a 6 inch string to it, and spin it fast enough to get the weight to fly out horizontaly. I wonder if the earth will have the same effect.
-William
God is everything science has yet to explain.
Oh you've got to be kidding me. Name one Adam Sandler movie that has not been a disaster.
I saw your presentation at Norwescon this year, and I was interested and impressed. My only really negative comment is that it seemed a little too much like a presentation by a .com trying desperately to convince people that you really had a viable business model.
I was really hoping for a sober engineering discussion that talked frankly about the problems and possible solutions. I thought your climbing robot was the most interesting part of the discussion. But when the 'vision' guy took over that to explain how you all had a chance in hell of making money on all this, I stopped being interested.
I think your company has a chance of succeeding actually. And your ideas about leveraging the technologies you create along the way in order to fund further R&D is are excellent. But talk that's all pretty powerpoint slides and slick presentation really turns me off. I'm not a businessman, and I don't think most of the people there were. I'm an engineer. Details and plain-talk matter to us.
As for stupid comments on Slashdot... I sometimes wish there were a '-1 counterfactual' rating, but it would get abused horribly to moderate down valid opinions people disagreed with. So the best you can do is to post truth and hope the moderators notice. Really, trying hard to control public perception of your company is going to backfire. It's just best to let people see what's going on and let them decide for themselves.
Need a Python, C++, Unix, Linux develop
Catastrophe. Yes Bad Things can happen. The amount of damage done is less than might be expected.
IS less? So this has been tested, has it?
I'll tell you what I'd expect. I'd expect if something went wrong and a "load" plummeted to earth from 5km up it would be pretty difficult to predict what sort of damage it would do... There's one of many possible catastrophes we'd like to hear whay you'd expect the damage to be
Terrorism. The thing is less a target than might be expected.
Again, IS less? This fact comes from where? A poll of known terrorists, or off the top of your head?
Yes, I know... people were executed for suggesting that the world wasn't flat, etc etc... but please - if you want a rational discussion on this thing pushing "facts" like these at us is hardly likely to sway any opinion.
Michael (the "vision" guy who talked during the robot demo) also gave a talk at Norwescon the previous night outlining many of the technical matters. Because the space elevator is a complex infrastructure project, technical discussions can go on for hours, so it can be hard to deal with people's questions in a one-hour talk.
FYI, there are plenty of people willing to discuss the technical (as well as legal, political, financial, etc. etc.) issues on our forums at http://www.liftport.com/forums/. Drop in, ask questions, read some of the alternate design suggestions, and see what you think.
I used to hang out on their forum a while back. One solution that was proposed was to "maypole" the tether when it enters the atmosphere - i.e., have it split and have a number of anchor points.
Edwards already had discussed several issues: one, the potential site, has almost no thunderstorms. Also, depending on the type of CNTs that you use, many are very resistive, and would not be the easiest route to the ground, but the most difficult. A risk factor, however, would be water streaming down the tether making a more conductive path.
sed "s/SJW.*$/... never mind. I was about to say something stupid, and also, I'm a troglodyte./Ig"
I am amazed at the lack of vision and basic technical knowledge most of the nay-sayers here on Slashdot display.
There is no doubt that it will take major developments in material sciences to make a SE practical. The possibility of breakage and sabotage would also have to be studied and mitigated. But right now, this is the only realistic possibility we have of becoming a space-faring species in the next couple of centuries.
An SE could lifts 10s of millions of tons of cargo into space each year. Once a critical mass of material and industry was in orbit it would be possible to colonize Mars and the Asteroid belt. Interstellar probes could be constructed and sent on their way. Trillions of dollar worth of palladium, silver, gold and platnium could be extracted from metallic asteroids to be used in manufacturing.
Is it risky, sure it is - but no more than crossing the Atlantic in a little wooden boat in the 15th century.
...would be to cable a suspension bridge with this stuff, and use that as a bellwether for issues with the real deal. It'd look kind of odd, because the carbon ribbon would be thread-thin compared with the normal steel cables.
Got time? Spend some of it coding or testing
There's no way a space elevator can be built with any kind of materials we know about today. Not even close. It's a fun idea to think about, but expect to see it built about the same time we invent warp drives and start learning new things from our Vulcan neighbors. Here are just a few thoughts of why off the top of my head, but there are easily hundreds of reasons more.
Move a wire through a magnetic field, and what happens? A current is induced in the wire, proportional to the change in the magnetic field (or, equivalently, the motion of the wire in a uniform magnetic field). Well, a space elevator is definitely moving, and the magnetic field it moves through is definitely not uniform. These currents would easily be enough to vaporize a steel structure like this. Ok, you say, make it out of something entirely non-conductive (i.e., non-metal). Out of what, rubber? Carbon nanotubes are very conductive, as you CS people should know. Try to build it out of something like diamond and it isn't strong enough. And you have to get something nearly entirely non-conductive, too, a high resistance won't work. If you don't know why, ask your oven, it knows. No known material ends up doing a good job at this.
The minimum energy curve from the ground to orbit isn't a straight line because of the Earth's rotation. The elevator couldn't be straight, or anywhere near straight. Consider that at the Earth's surface, we move around at a "horizontal" speed of about 1047 mph (1685 kph) (4000 mi * 2 * pi / 24 hours), at a geosynchronous orbit we're at 6860 mph (11040 kph). That means to move on a straight line you need to be changing your horizontal speed by a few thousand miles an hour! I.e., you'd need a force pushing sideways on your elevator and tower to keep it straight, but unless you want to put rockets on the sides of it, there's nothing you can do to add that kind of force, so you need to make it curved, like an Archimedean spiral, in fact. But, with it shaped like that, you've got a very tall curved structure, and gravity is still pulling it straight down. So it turns out you need to make it out of a much stronger material than you would for a straight tower on a non-rotating Earth.
Any object when heated is going to expand, which is a non-trivial effect even for small objects. Look at concrete bridges, even small ones, for example. Periodically there are gaps in them an inch or so wide, to allow for thermal expansion of the bridge, if those gaps weren't there, the bridge would break. Bridges even only on the order of tens of meters long need these. A space elevator obviously couldn't have gaps, and will be on the order of thousands of kilometers! This means there will be *significant* changes in where the top of the elevator is, which means you need a significant change in the angular momentum at the top of the tower to keep it from collapsing. Of course, that's only if the tower is straight, if it's spiral-shaped, like a real one would need to be, you've got a much more serious problem, because the shape of your spiral just changed! You've got even more of a problem when you consider that the temperatures along different points of the structure will be different, and will be constantly changing, particularly the points near the top--what's the temperature of an object in space in darkness vs. direct sunlight!? And then there's the problem that this will cause the strength of the material the elevator is made up of to change, too! So you end up with an elevator that's longer than it was a minute ago, weaker than it was a minute ago, and no longer the same shape, trying to do the same job!
But that's not all, you also have to consider that deformations only propagate along the structure at the speed of sound in the material. This isn't an issue in a small structure, but one that's 100,000 km high, it's a serious issue! When part of the structure expands or contracts the whole thing won't move instantly! There will be serious waves of compression and expansion propagating through it. The structure will *bend* because it can't move out of its way fast enough for its expansion.
The Space Tethers will be built far sooner and are really much better. These can toss you into space fast so you don't fry in the radiation belts, recycle the energy from payloads going down into payloads going up, and be built with materials we have today.
I highly doubt anyone here can even walk one flight of stairs, let alone a thousand. I'd rather sit and starve.