Space Elevators Problems

New scientist is carrying a story about the problems of making a space elevator. Rather than thinking about the significant problems of fabricating such a cable, when no materials exist of sufficient strength, they are now talking about the problems of radiation from the Van Allen belts. The length of time spent in the Van Allen belt may be several days in current designs which envisage elevators travelling at 200 kilometers per hour. Solutions to this problem mean increased weight of the carriage or cable.

Read the New scientist article


7 Responses

  1. To be fair to the New Scientist – it’s their job to report the news not think about problems. Thinking about problems is our job.

    The fuss that has been kicked up over this is astounding. This is a problem until you sit down and think about it for a second – we’ve known how to protect against radiation for, oh, a long time now. Distance or something to absorb the radiation.

    Tanks of water around the passenger compartment will do nicely.

  2. I don’t think it’s really news, in my opinion the space elevator is science fiction rather than science for now. The claims that people make are fantastic.

  3. I’ve noticed that the further from the nuts and bolts of the idea that people are more speculative and fanciful they become.

    When you get closer to the idea and start mucking around with the tedious bits and actually start working on the numbers you’ll see more cautious hedging and ‘what if’ing.

    LIke this: we (that is Liftport) don’t know for sure that we can build a space elevator, and that if the really hard technical problems can be set aside then if it can be done by a private organization. More, there needs to be a political and regulatory climate to operate in or it can’t be done at all.

    However the basic idea is feasible. We keep running up against problems that have workarounds so no absolute show-stoppers as of yet. We’ll see what happens.

    Brian Dunbar

  4. Yeah it can work, apart from not having any material to build it from. I’m sure that some useful progress can be made but I think the claims to date are unreasonable. The strength of materials on the nanoscale can’t be extrapolated to the micro or macroscale.

  5. I’ll defer to your knowledge on materials but will note that Brad Edwards has been carrying around a sample CNT composite for a few years that (I’m going by memory here) as a 1 Giga Pascal factor. Which is shy by quite a bit.

  6. It’s not my area of expertise, if you have any reference for 1 GPa in bulk material I would be interested.

    According to this paper:

    A 460 nm length nanotube has a strength of 150 GPa [1] whilst a 2 mm rope will have a strength of 1.7 GPa [2].

    [1] B.G. Demczyk, Y. M. Wang, J. Cumings, H. Hetman, W. Han, A. Zettl and R. O. Ritchie, Mater. Sci and Eng. A 2002, 334A, 173-178.

    [2] S. Xie, W. Li, Z. Pan, B. Chang and L. Sun, J.Phys Chem Solids, 2000, 61, 1153-1158.

    (not logged in as bainite)

  7. It’s not my area of expertise, if you have any reference for 1 GPa in bulk material I would be interested.

    Matthew, I’ll try. I may have the facts muddled – recall that I’m merely a computer guy; we’re all long past the era when it was possible to be a subject matter expert in diverse fields the way Newton could.

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