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Notes From 3rd Annual Space Elevator Conference
colonist writes "The Space Elevator: 3rd Annual International Conference was held recently. Blaise Gassend, a PhD student at MIT, took notes. The main obstacle is still the material: transferring the strength of the nanotube to the ribbon. Other topics include: the nanotube tether Centennial Challenge; Elevator 2010, a challenge for a 250 kg climber to climb a 16 km tether; objections and refinements to Bradley Edwards' design; non-equatorial space elevators; replacing the term 'space elevator' with 'space bridge'; testing the space elevator material on cable cars; science; defense and economics."
This will change everything. Transporting to space will be (relitive to rockets) DIRT CHEAP. Props to them for their vision and their crazy idea that just might work.
This page seems to have some good links. Just check out the bottom of the page as it indicates if you're new to the idea of space elevators.
How on earth are they going to cope with the wind forces, the jetstream, gravity, the earths spin, earpopping, in transit entertainment, lightning, costs, kids, aliens, terrorism and the fact that their's nothing in space to go up to yet.
P.S.
EMACS already does this.
May the Maths Be with you!
Wikipedia have a very good article on space elevators
The point is that it's an extremely energy efficient way of hoisting stuff into space (in theory).
Better to have a comparably near zero cost elevator than spending gadzillions launching a moonbase into space piece by piece using rockets.
The space elevator is a great idea but no human has the mental strength to listen to elevator musak for the length of time the trip will require and still retain their sanity.
Do not try to read the dupe, thats impossible. Instead, only try to realize the truth
What truth?
There is no dupe
I think that it should be taken into consideration that almost every major project of construction was deemed impossible. Very good examples of these are the famous Golden Gate Bridge and the EuroTunnel. Everyone said it was impossible, yet they were completed. As technologoy in this area continues to develop, I think that this may be able to become a real and practical idea sometime down the road. It may not be possible now, but in ten years, who knows?
Ursäkta, men jag fattar INTE vad du säger?
SIG: TAKE OFF EVERY 'CAPTAIN'!!
I believe the point is to make access to space economically practical. Burning massive amount of fuel is pricey and pretty bad for the environment. If we really want to be doing stuff in space we either use space elevators or wait for someone to invent anti-matter drives or something.
---
We spoke for about a half an hour. I don't recall a thing we said. - Colorblind James Experience
Blaise Gassend's page mentions Andrew Price's list of alternative names:
space bridge
space way
space rail
'Space bridge' got the most approval from the audience.
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.
-The Libra
"Please be patient--The future will begin momentarily."
Not in the fairytail....
But there is archeological evidence for a lot of towers in what is now Iraq and Iran.
Among them some very big ones in babylon.
Jeroen
Secure messaging: http://quickmsg.vreeken.net/
so the terrorists won you already?
how does the shuttle cope with being exploded? it doesn't. how would spaceshipone cope with it? it doesn't. how woul....
they're not going to be able to design it to be invulnurable to everything possible of course, that's where groundside security comes in.. it needs a no flight zone & etc anyways.
world was created 5 seconds before this post as it is.
16km is a little too high for a helicopter (they top out at about 7-8km), but it's well within the reasonably altitude range for a large helium baloon.
According to new Nasa research http://www.nasa.gov/news/highlights/index.html they can fully fund a new US$2 billion research project by selling the franchise to the revolving restaurant at the top and logo placement along the length of the ribbon itself. Already, they have received competitive bids from Chez Panisse, McDonalds, and Bert Farnsdale's New York hotdog stand. This is the start of the holy mothership of bidding wars.
consider coffee a lubricant that helps one penetrate the coding zone
are you out of your mind or just lost the touch with reality completely??
you won't EVER create such a world, there's always going to be someone wanting to spoil the party for the rest(US has even domestic troublemakers). so if you take the attitude that you won't do anything before they're settled down... guess what? you'll end up doing nothing.
world was created 5 seconds before this post as it is.
Not insightful... just flamebait... Are you also concerned about terrorist attacks on satellite launches or the X-Prize?
We're talking about an isolated platform in the middle of the south pacific ocean with nothing around it for hundreds of miles..... there have to be better targets for a terrorists with ICBMs at their disposal.
Get real... this is not political.... and it is virtually isolated from any sort of assault, whether it be from China or from Osama...
The only reason the towers were vulnerable is that they were within range of a very short sighted attack... which had no impact on our security, our national security... but only caused devastating damage to innocent families.
A fool throws a stone into a well and a thousand sages can not remove it.
The Spaceward Foundation is creating the Elevator:2010 program:
If we suddenly have 100 miles of superstrong material slamming down at hypersonic speed, it's going to be extremely bad - somebody ought to calculate how many Teratons of TNT that corresponds to.
Just about 0 Teratons of TNT IIRC. The carbon nanotube ribbon proposed doesn't weigh much and has awful aerodynamics, and for the most part would just flutter down. And that's only the part below the break point, which is going to be pretty low, if it's planes were worried about.
They have to be to hold the darned thing in place. I doubt something as feeble as a passenger plane crashing into it will do much damage other than making it vibrate for a bit. I don't envy the people on the plane, though.
Stick Men
If we suddenly have 100 miles of superstrong material slamming down at hypersonic speed, it's going to be extremely bad
It'll be more like a 100-mile piece of paper fluttering to the ground. The ribbon will be extremely light. It needs to be, or it can't hold up its own weight. Why don't you go read the Space Elevator FAQ before displaying your ignorance?
Any sufficiently advanced libertarian utopia is indistinguishable from government.
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.
What happened to the intermediate designs that don't provide all the benefit but also don't require two decimal orders of magnitude performance improvements? I didn't see anything in the
Brin's electromagnetically boosted tether design (Tank Farm Dynamo, 1983) would reduce the amount of delta-vee needed for orbit, at least allowing for cheaper shuttles. It's not much of a benefit, but we could build it today.
A rotating tether that dipped into the atmosphere would allow much greater safety margins and have a much less dangerous failure mode. You could practically rendezvous with one from an X-prize vehicle, and you wouldn't need to build a climber... just grab the tether, hold on for one rotation, and let go.
The big problem of course is that extra delta-vee isn't free, and the tether would lose altitude every time it's used (this is a problem for all tether designs, really). So, the throughput rate would be limited by the time needed to re-boost the tether between launches: using a high-efficiency low-thrust drive would be cheapest but require the longest "recharge" time.
Longer term, it would get a boost from de-orbiting mass from space: if you return a ship of the same mass to Earth at the same time as you boost one to orbit the net delta-vee is zero. If you have more ships going up than coming down, bring a nickel-iron asteroid into orbit and just feed a chunk of metal that weighs the same as the ship in from a higher orbit, it'd get de-orbited and released at 100km. Make it in an airfoil shape (a crude glider) and you can recover it... just deliver it to an asteroid-iron junkyard out in the middle of New Mexico or something.
THAT would make Rutan's barnstormer spacecraft a stage in developing a new industry, instead of a stunt.
We can't change its name to be a 'space bridge'. If we did, we couldn't have the same hilarious jokes in every Slashdot article about elevator music.
Won't somebody please think of the hilarious Slashdot jokes?
The America / "The West" actually gets off its backside and builds it before China decides to.
Ripping an new rectum in the fabric of spacetime.
Following up to myself: here's a link to a page about a variety of tether-based designs and experiments: Advanced Propulsion Concepts.
The text of Tank Farm Dynamo is online.
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?
Charlie and the Chocolate Factory was teh awesome!
"Come with me, and you'll see.... A world of pure imagination...."
How can you dis? You got a beef with an oompaloompa?
Sleep is futile.
you're forgetting the big upside of the space elevator: the owners of the space elevator can drop shit on you from space! heavy things like big rocks, kitchen sinks, and 2000 pound gps-guided bombs. and let it be clear, there is no defence against kitchen sinks falling on you from space. we're talking afforable space based weapons platforms. the weapon of choice of the future may be raindrop-shaped ceramic projectiles with spent-uranium cores, raining unstoppably from above and smashing their way through tanks and into underground bunkers, or sinking an aircraft carrier battlegroup.
the military of the country that builds this wonderous weapons platform will let see to the safety of the tether, you can bet on that.
I wouldn't worry about being killed by a carbon fiber making meteoric reentry. It wouldn't be like the disaster in the Mars trilogy, or even like shadow square wire... by the time it hits it'll be more like laser toner, the stuff is strong in tension but it burns quite nicely: Nanotube Explosions
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.
Simple - have more than one tether.
You could have say 5 tethers, anchored in a pentagon shape on the ground, where the sides of the pentagon are maybe 100km long. Same sort or arrangement at the top - they all connect to the same asteroid, just a little distance apart.
If any one tether is destroyed, the rest will be enough to hold things together until the broken one is replaced.
Meanwhile, under normal conditions, you have 5 times the capacity.
Yes I know it'll cost more, but if you want redundancy, you gotta pay for it.
While Arthur C. Clarke certainly popularized the idea of a space elevator in his science fiction novel "The Fountains of Paradise", the original concept is credited to the Russian engineer Yuri Artsutanov, who published it in 1960. See, for example, here
Ubi dubium ibi libertas: Where there is doubt, there is freedom.
My web domain.
In the effort to increase public comprehension of this concept, I offer up "space yo-yo".
The sailor's rule only applies when the rope is hanging down, it has to support its own' weight, yadda, yadda, yadda...
But, you see, this rope will be hanging "up" so to speak, and therefore conveniently bypassing any such rule. If my calculations are correct, since this rope is going in the negative direction, its strength will increase, rather than diminish, by orders of magnitude!
If you don't know what AltaVista is (was), get off my lawn.
Harsh? Yeah.
--- Ban humanity.
Consider the ultimate composite nanotube material -- stiffness 10^12 Pascal, yield strength 10^10 Pascal. So at-yield, it stretches 10%. The stored elastic energy density then is 5x10^9 J/m^3. This is roughly the same stored energy as an equal volume of TNT (4.1x10^9 J/ton)! Yikes! You can think of the deployed nanotube bridge as a gigantic PrimaCord detonating system.
Most plans I've seen for one of these involves starting construction on a second using materials lifted by the first.
Makes sense, as the second one would cost 1/100 of the first, doubling your capacity and reducing the chance of a breakage making you lift replacement materials by the expensive method again...
I don't read AC A human right
Waltz, nymph, for quick jigs vex Bud.
In addition to what's already been posted about it falling like a piece of paper (it'll actually be lighter than paper), it should be noted that unlike the WTC which was between 3 airports (not a no-fly zone) and undefended, the base station would probably be a couple hundred miles offshore, in the middle of a large no-fly zone, with plenty of defence (just park an aircraft carrier nearby).
Current proposals for implementation of the Hans Moravec's original design rely on a hypersonic air-breather of advanced aerodynamic design like the Boeing DF-9 (that exists only on paper).
Can /. readers think of anything likely come along in the near future that could take
paylods to 100km and mach 12?
Probably the same thing that is driving the bureaucrats to make all this noise about space elevators now.
A key to the Rotovator(tm) is getting hub mass in place to keep it out of the atmosphere while it picks up mass from 100km@mach12 -- but that mass can be any old space junk -- at least at the hub where it counts the most for high strength materials like carbon nanotubes. However, you can do a Rotovator(tm) with off-the-shelf commercially available fibers and still have a factor of 2.
Nice thing about Rotovators(tm) is that they can be built with much lower capitaliztion over a much shorter period of time using existing commercial materials. All you need is a bunch of mass orbiting near earth, some quite-doable tethers, and sufficient manuverability and speed in the atmospheric leg to hook up with the tether as it reaches the nadir.
Seastead this.
_The Fountains of Paradise_, by Clarke. A good read, too!
And what if the tether breaks and drops on Earth
1. Everything above the cut would stay in orbit. Everything below the cut would fall to Earth. The base will be on the West side of the Atlantic Ocean and will therefore have hundreds of miles of water to its East. Most of the dangerous things that can cut it are in LEO, which is less than "hundreds of miles" away. So more than likely everything that falls to Earth will fall into the Ocean.
2. Just because the cable has high tensile strength that doesn't mean it is indestructible. You can bind a person's hands with speaker wire and no matter how strong the person is, they wont be able to break free. But that doesn't mean the wire is magically indestructible. It's just wire.
3. In the current issue of Discover Magazine, the concept they write about calls for a cable a few feet across, but only as thick as a sheet of paper. I don't know why so many people assume we are talking about an elevator to lift humans. The first several incarnations will be for light cargo only. Anyway, a cable as thin as a sheet of paper will mostly burn up as it falls through the atmosphere. If any of it survives, it will be shattered into pieces (not together as a whole cable) and will have the same terminal velocity as a sheet of paper. It will just flutter to the ground without hurting anyone. If you are lucky enough to live in the debris path, you can collect the stuff up and sell it on ebay.
So many people make the mistake of assuming that there is some horrible danger that only they will recognize. As if hundreds of scientists around the world are diligently studying this and then Frans Faase of slashdot comes along and says, "what about this problem here?" And all those scientists will just throw up their hands and say "oh god, we all have PhDs but we didn't think of that - we aren't as smart as Frans." Right.
Don't forget the really big rocket you need to attach to the kitchen sink in order to kill nearly all of its momentum so it doesn't just sit there in orbit with you making you look really foolish.
Conferences like these always give me a lift.
I wish I had modpoints. Rotovators are indeed much more practical than space elevators. They do not require exotic new materials such as carbon nanotubes. They can be built with cheap materials like spectra or zylon fiber. They are also much shorter (100km instead of 36000km) and more flexible.
This system could double the payload capacity of launchers to geosynchronous transfer orbit or pick up small payloads from suborbital trajectories.
This could be built today. Rotovators are also a very good addition to suborbital space transports such as SpaceShipOne.
Private property is the central institution of a free society (David Friedman)
"Elevator 2010, a challenge for a 250 kg climber to climb a 16 km tether"
How about something possibly a bit more realistic, like a 250kg climber climbing a 50 meter tether.
The problem that I have with the space elevator fanatics is that they are setting goals well in advance of the science and engineering which usually leads to disillusionment and could scare away investors in what is a promising area of development. Carbon nanotubules hold great promise, but it is still just promise until they can be manufactured in suffient lengths and with sufficient ease to be practical for any use let alone a space elevator.
If carbon nanotubules are going to be useful, we will see them used as building materials for much smallers things first. Perhaps as robotic tendons, or longer bridge spans, weaved into lighter armor for vehicles... I could think of many important applications which could use shorter easier to make lengths of nanotubules and would provide the neccessary experience to determine if a space elevator might be practical.
Sometimes small steps are big.
I guess that by "really weird book" you mean The Fountains of Paradise by Arthur C Clarke?
Mmmmm, cowardice.
-PS
"All that is necessary for evil to succeed is for good men to do nothing." - Edmund Burke
"Unaddressed are...the way it would wrap around the equator when it tries to lift any significant mass (most of orbital launch acceleration is horizontal, not vertical)." The climber would drift westward, and the net bend in the ribbon would impart a horizontal eastward acceleration. (The angular momentum gained by the climber comes from the earth. ) You can think of the elevator as the world's largest stringed instrument. A climber falling off in mid-climb would pluck it.
However, if you take the train, you go from downtown london to downtown paris. If you're on one of the French high-speed trains, the trip is only about an hour longer than it is by air. Factor in the fact that you can clear customs on the train rather than on the ground after you land, as well as the hour+ drives/cab rides to and from heathrow and charles de gaulle airports, and the train is actually faster for buisiness commuters by at least an hour. Now, there's not many people whose time is worth 149 - 64 = 80 GBP/hour, but they do exist.
There's other reasons, mostly regarding how train travel is generally more pleasant than air travel, and then theres the fact that you can bring your car across to calais from britain, but I found the revelation that the train can be faster door-to-door to be particularly insightful.
The main thing this is good for is for propulsion. A rotating tether can pickup and toss payloads but it looses some momentum unless there is other traffic going the other way. But with an electrodynamic tether pushing on the Earth's magnetic field you can get momentum without using rocket fuel. This is way cool.
To quote the original Bradley Edwards paper "The Space Elevator",
"The segments of the cable in Earth's radiation belts will experience less than 3Mrad per year (energetic electrons and protons) [Daly, 1996]. Studies of epoxy/carbon fiber composites (epoxy/nanotube composites would be expected to be comparable or better) have found them to be radiation hard to greater than 10^4 Mrad [Egusa, 1990: Bouquet, 1979]. This would allow them to survive more than 1000 years in the expected environment"
To survive the atomic oxygen, it was proposed the ribbon be coated with a thin layer of metal (aluminum, nickel or gold) between .02 and 20 microns thick. This would only be applied where atomic oxygen is a likely hazard
Finally, it is understood that the ribbon will degrade over time despite best efforts, due to radiation, electric discharges, micrometeorite damage, fiber/epoxy failures, etc. They talked about a plan to periodically inspect, and, if necessary, reinforce the ribbon with additional strands of material.