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 ---------------------------------------------------------------------- Date: 27 Dec 1981 1936-PST From: Jim McGrath 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 ------- ------------------------------ End of SPACE Digest ******************* ----------------------------------------------------------------- gopher://quux.org/ conversion by John Goerzen of http://communication.ucsd.edu/A-News/ This Usenet Oldnews Archive article may be copied and distributed freely, provided: 1. There is no money collected for the text(s) of the articles. 2. The following notice remains appended to each copy: The Usenet Oldnews Archive: Compilation Copyright (C) 1981, 1996 Bruce Jones, Henry Spencer, David Wiseman.