Re: Question: space elevator

Hop David wrote:
CG wrote:

thanks, I missed seeing that group when I was
looking at ones to subscribe to and was trying
to find the best place to ask.


A good book to read is _Fountains of Paradise_ by
Arthur C. Clarke.

The main character, Vannevar Morgan, starts with an orbit
in geostationary orbit. A circular orbit at an altitude of
about 36000 kilometers will have a 24 hour period. From our
point of view, an object in geostationary orbit will appear
to hove motionless over a spot on the equator.

Morgan then builds simultaneously down and up from the
geostationary object. The portion below exerts more of a
gravitational tug and is lifted by less centrifugal force.
For the portion above, exactly the opposite is true. Morgan
plays a balancing act so the the object stays in
geostationary orbit until it touches down.

I think I remember Clarke's description of the cable-laying
operation much as you describe it, but it sounds odd to me.
My intuition says that the space-station/cable combination
would stay in GSO (by which I mean "will stay over the same
patch of ground") no matter how you reel out or reel in the
upward or downward cables, although I haven't worked it out
yet.

It seems to me, if you can alter their orbit, you've produced
torque somehow from a central force (earth's gravity). This
would at the least be interesting, if true. Also, the effect
could be used for satellite station-keeping by mechanical means,
instead of using jets.

One thing I can see is that if the extension of the cables is
far off balance, then the space station will move outward or
inward and experience a net gravitational/centrifugal force.
I suppose this could be called "leaving geosynchronous orbit",
if we're referring to just the space station. Perhaps this is
what you and Clarke were referring to.

Jim Burns
.

Relevant Pages

  • Re: OT? Why Doesnt the Moon Fall Down?
    ... far distant future settle in a geostationary orbit? ... but my understanding is that the moon's orbit ... Robert Grumbine http://www.radix.net/~bobg/ Science faqs and amateur activities notes and links. ... Sagredo (Galileo Galilei) "You present these recondite matters with too much ...
    (talk.origins)
  • Re: Just so you know.
    ... A geostationary orbit was first described by A.C.Clarke. ... It's only geostationary if it remains over the same spot on earth, ... and is called gravitational potential energy. ...
    (rec.games.frp.gurps)
  • Re: OT? Why Doesnt the Moon Fall Down?
    ... far distant future settle in a geostationary orbit? ... It has been explained why the moon is moving away. ... but my understanding is that the moon's orbit ...
    (talk.origins)
  • Re: How on earth are we going to comlete the space elevator
    ... too much reletive movement between the earth and the orbit for such a ... This depends on the orbit. ... center of the Earth, there's no relative movement. ... So we just have to put a big cable in geostationary orbit, ...
    (sci.space.shuttle)
  • Re: Is LIGO just observing viscosity of the vacuum?
    ... orbit around the Sun for 4+ billion years. ... Roughly speaking, it's because electromagnetism allows dipole radiation, ... while gravity allows only quadrupole and higher radiation. ... radiated power goes as the square of the second derivative of the dipole ...
    (sci.physics.research)