[extropy-chat] FWD [forteana] Re: lunar elevator

[Dan Clemmensen]

Mike Lorrey wrote:

>--- Eugen Leitl <eugen at leitl.org> wrote:
>  
>
>>>get away from the geostationary altitude, the more force
>>>tangential to the orbital path is required to keep the system
>>>linear and stable.
>>>The orbital velocity has to be reduced approaching the planet//moon
>>>and increased in the opposite direction. You'd end up not with a
>>>perfectly straight cable, but a curved one, in the manner of the
>>>curving waterfalls in AC Clarke's Rendezvous with Rama.
>>>
>>>Perhaps somebody with more maths than I have could explain if I've
>>>got the wrong end of the stick (or lift cable), but space elevators
>>>do sound like a bit of a non-starter to me.
>>>      
>>>
>
>An earth cable would curve because of lunar tidal influence only,
>putting tidal drag on the ends. A lunar cable at the inner lagrange
>point would be tidally locked with the moon, and would be curved by the
>tidal drag of the Earth. However, this only assumes that there is no
>other tension. If, for instance, the CG of the skyhook is slightly
>higher than geostationary orbit (or just earthside of the inner
>lagrange point), and the ground end is anchored sufficently, tension
>will keep the cable taught.
>
>Because the system is in tension from these forces, anchoring the end
>to the ground will translate tangential forces into tension forces that
>are merely pre-existing frame dragging forces in the earth-moon system.
>
>  
>
How important is nutation?