From: Monte Davis 

"Rich Gauszka"  wrote:

>looks like carbon nanotubes and a space elevator will only be a dream of
>science fictions writers - sigh

Best to reserve judgment for  a while. The consensus on individual nanotube
strength hasn't settled down yet, although the trend of the "median
guesstimate" has been downward over the 5-6 yeras since Edwrads began
beating the drum for space elevators. Theoretical figures depend on your
choice of quantum-mechanical modeling assumptions, and on how well you
understand the mechanisms of C-C bond rotation and breakage (not very).
Even numbers from actual stretch-it-til-it-breaks tests are all over the
lot; it's *hard* to clamp firmly onto a tube that's just 12 atoms or so
around without introducing artifacts.

Pugno is quite right about the strength of bulk CNT-based materials so far.
Because the basic science is still hazy, there's been very little work on
the nano->micro "bundling" that would get you 6 orders of
magnitude from a single CNT to a fiber that process engineers could begin
to work with. Every macroscopic sample announced so far has been very
slapdash in length and orientation -- like pressing dust kittens, hair
clippings and old kite string into a cylindrical form and calling it a
hawser.

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