sal wrote:

you don't get a lot of help with horizontal thrust from the cable
unless it's seriously bent -- one would not expect the cable to act very
"stiff"

It doesn't need to be. You're acquiring that GEO orbital velocity over
more than a week; the "sideways" acceleration is small, and easily
supplied from the restoring force that's trying to keep the ribbon
vertical and taut. People keep thinking about the flimsy part we
build, and forgetting the six-sextillion-ton flywheel at the base...

But again that's one of the obvious in-your-face problems which
needs to be addressed

And was, years ago. A beanstalk SE simply isn't going to happen in
the foreseeable future unless the cable can be much, much, much
lighter than the multi-billion-ton versions in Red Mars, Fountains of
Paradise, and Web Between the Worlds. IIRC, Edwards' baseline is ~800
tonnes for the finished ~100,000-km cable. Do the math: the mass per
m^2 is comparable to newsprint or plastic food wrap.

I have lots of doubts about space elevators, but jeez, I wish we could
get past the Red Mars disaster scenario.

Monte Davis
http://montedavis.livejournal.com