Re: Re: [OT] Beanstalk anyone?

Popeyesays wrote:

>A beanstalk top would be geo-stationary, would it not. It would not
have 
>much angular momentum and would at most drift away and be recoverable
for 
>some time.

I thought about this some more, and here's what I realized:

When dealing with an untethered orbiting satellite, this is true.  But
not 
necessarily for a tethered beanstalk end.  Here's why:

Remember the old image of a phonograph.  The farther from a certain
point 
you are, the greater your linear speed must be to maintain the same rate
of 
rotation (rewvolution?).  The opposite is true for orbiting:  the
greater 
the distance from the center of mass, the LESS velocity needed to
maintain 
orbit.	So the farther a satellite is from the earth, the slower it
needs to 
go to maintain orbit, but the faster it needs to go to stay directly
above 
any given point on the surface.  Geostationary/geosynchronous orbits are

maintained at the distance at which these two velocities match (on a
graphof 
velocities, at the point where the two lines cross).  If you set the end
of 
a beanstalk at that altitude, sure, if the module on the end ot the
stalk 
were detatched, it would probably maintain orbit.  But if it extends
further 
out, two things will happen:  the beanstalk is going to be pulling it
along 
at greater velocities in order to keep up with the base point on the 
surface, and the necessary orbital velocity will DECREASE.  That means a

stalk end set further out will be tugging at it's stalk, since it will 
probably be at escape velocities.  if untethered, it should go flinging 
away.

Or am I missing something?

3B^2

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