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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."

10 of 469 comments (clear)

  1. Re:More space elevator details? by DrMrLordX · · Score: 5, Informative

    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.

  2. Re:More space elevator details? by Deag · · Score: 5, Informative
  3. Frontiers of Construction by feilkin · · Score: 5, Interesting

    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?

  4. Re:Playing too much Civilisation by Anonymous Coward · · Score: 5, Insightful

    Christ, why does everything we ever dream of nowadays have to consider terrorism as an influencing factor? What is this obsession with living in fear all the time? Have we been so indoctrinated that we now automatically think in these terms? I say screw the "terrorists" whoever they may be. Perhaps if we spent more time dreaming and less time trying to fight fear with fists we'd be a lot better off anyways...

  5. The Sailor's Rope Rule by TheTXLibra · · Score: 5, Interesting

    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."
    1. Re:The Sailor's Rope Rule by vidarh · · Score: 5, Informative
      What this is essentially saying is that the rope needs to be able to support it's own weight in addition to the weight attached to it, which means that the longer the "rope" you need the lighter it needs to be compared to it's strength for you to be able to lift any reasonable amount of mass, or for it not to be torn apart by it's own mass.

      That's why you need a really strong material for a space elevator - if it wasn't for the weight of the "rope" itself you'd only have needed a material strong enough to handle the weight of whatever you wanted to transport up it, but that is a miniscule amount of the total strain on the elevator.

    2. Re:The Sailor's Rope Rule by Fzz · · Score: 5, Informative
      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...

      Ignoring the weight of the rope itself, probably the main reason for this rule-of-thumb is the difference between dynamic loading and static loading.

      If you (accidentally) get something bouncing on a short rope, the bounce will damp out pretty quicky and the period of oscillation is short. If you get something bouncing on a long rope, it will bounce for a while, and the rope is stretched for much longer with each bounce. It doesn't take all that much of a bounce to double the load on a rope, and perhaps take it past its elastic limit.

      I'm guessing, but I think that pre-synthetic ropes probably can be briefly overstretched without losing strength because they knit back together again. If you continuously overstretch them, the fibres probably don't get a chance to recover before the slide past each other a little more, and so on.

      So my guess is this doesn't apply nearly so much to modern synthetic ropes. In the case of a space elevator, I'd hope they'd try really hard to avoid excess dynamic loading.

  6. Feasibility of the Space Elevator. by Dissectional · · Score: 5, Interesting

    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.

  7. Re:Playing too much Civilisation by ctr2sprt · · Score: 5, Insightful
    Oh, come on. Your first thought upon hearing of the space elevator wasn't "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. As long as you don't let it make the decision for you. Saying "We'll increase the no-fly zone from five miles to twenty five to give us time to shoot down hijacked planes" is good planning. Saying "We just can't eliminate the possibility of terrorism, let's just not build a space elevator" is not.

  8. Re:Playing too much Civilisation by Anonymous Coward · · Score: 5, Insightful

    Actually, it wasn't. My first thought was, "cool", but hey...

    What really irritates me is that this fear of terrorism is so unreasonable. It's almost akin to the "Won't someone think of the children scenario". The US has been the target of relatively few domestic attacks and of those, one was carried out by a US citizen. Despite this, the fear of terrorism has pervaded the national consciousness so fundamentally that any discussion is now subject to these apocalyptic "what if?" scenarios.

    Yes it would be a very bad thing (tm) if someone crashed an airliner into a space elevator, but when that progresses from being a notable, if incredibly unlikely concern, to a point where such fear of the irrational drives society itself, then who cares what the "terrorists" do, they've already won. Of course we should build with the lunatic with a cause in mind, but build we must. This realisation is slowly being eroded. There is a phoenix risen from the ashes of 9/11 filled with hatred and fear, and it is a frightening beast indeed.

    Europe has had to live with this for far longer than the US, yet they live in a far freer, far more secure environment than we could ever hope to have. I re-iterate, screw the terrorists. It's the only way we all win.