Aucbvax.5639
fa.space
utzoo!decvax!ucbvax!space
Mon Dec 28 03:17:43 1981
SPACE Digest V2 #72
>From OTA@S1-A Mon Dec 28 03:03:47 1981

SPACE Digest                                      Volume 2 : Issue 72

Today's Topics:
                               North Pole
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Date: 27 Dec 1981 1936-PST
From: Jim McGrath <JPM SU-AI AT>
Subject: North Pole
To: space at MIT-MC


First, you CAN have a skyhook at the North (or South) Pole.  In
theory, these are the only two spots on the earth which do not rotate.
There are, in fact, slight precessions that give you difficulties,
especially since the skyhook's horizontial position (like an
equatorial one's vertical position) is at an unstable stable point (ie
the moment it gets out of wack the displacement tends to get larger,
not smaller).

However, all this speculation is really meaningless because a skyhook,
in the sense we have been talking about, cannot be placed at the
poles.  Why?  Well, our skyhooks rely upon the tension created
throughout the structure by the rotation of the earth.  At the poles,
this tension cannot be generated (since the structure does not
rotate).  Thus the weight of the structure has to be supported by the
base, just like any other building.  I am not sure we could build such
a structure (I have not cranked the numbers) , but clearly the polar
skyhook scheme has no ADVANTAGE over the equatorial one.

Second, I am puzzled that no one has mentioned the obvious solution to
the SPS power beaming problem.  Naturally the power transmission from
space to ground is done via superconducting cables along a skyhook.
So why not extend this logic further?  Instead of beaming the power
from the SPS to the skyhook (incurring transmission losses, conversion
losses, and still some safety problems), simply string a
superconducting cable from the SPS to the skyhook!  That is, do not
use beam transmission at all - always use cables.  This cuts your
transmission losses to near zero.  If you are generating electricity
directly at the SPS, then you never do any energy conversions - if
not, then only one conversion is needed.  And you have eliminated all
safety problems.

Jim

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End of SPACE Digest
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