(Mister Sharkey) writes:

(Jordin Kare) wrote in message . ..
The basic design is a 100,000 km by 1-meter by 1-micron-thick ribbon of
carbon-nanotube composite fibers, mass around 80 tons, with a 20 ton
load capacity. The "climbers" use simple friction drive (treads clamped
around the ribbon) to go up the ribbon at 200 km/hr, taking about a week
to reach GEO.

In the reports I have read, the designs always call for a ribbon of
carbon nanotubes. Why a ribbon, and not a cylindrical cable? Would a
ribbon be stronger, or easier for the climbers to climb, or what?

It minimizes the mass of the cable, because the load of each climber
is distributed over the maximum possible number of nanofibers
(namely, =ALL= of them) without having to transfer _any_ of the load
via shear-stress on the cable matrix.

It also makes the cable easier for the climbers to climb, because for
a given amount of material, it provides the maximum possible surface area
for the traction rollers to grip against (i.e., =ALL= of the cable is
"surface area").


-- Gordon D. Pusch

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