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From: chiaraviglio@husc2.UUCP (lucius)
Newsgroups: sci.space
Subject: Re: Powersats
Message-ID: <1009@husc2.UUCP>
Date: Mon, 3-Nov-86 22:44:02 EST
Article-I.D.: husc2.1009
Posted: Mon Nov  3 22:44:02 1986
Date-Received: Tue, 4-Nov-86 07:46:26 EST
References: <531179395.amon@h.cs.cmu.edu> <1575@jade.BERKELEY.EDU> <1577@jade.BERKELEY.EDU>
Organization: Harvard Univ. Science Ctr., Cambridge, MA
Lines: 51
Summary: My mistake. . . .  Also a question of general interest.

In article <1577@jade.BERKELEY.EDU>, c60a-2jm@tart15.BERKELEY.EDU (Adam J. Richter;260E;;) writes:
> In article <1007@husc2.UUCP> chiaraviglio@husc2.UUCP (lucius) writes:
> >In article <1575@jade.BERKELEY.EDU>, c60a-2jm@tart23.BERKELEY.EDU (Adam J. Richter;260E;;) writes:
> >[Reference to Scientific American article, and explanation of how
> >phase-conjugate mirrors work, deleted.]
> >> 		Small guide beam --> LEO powersat.
> 				     ^^^
> >> 		LEO powersat --> LOTS OF ENERGY focused almost
> 		^^^
> >> 			perfectly back down the "guide beam."
> >[                       . . .from an amplifying phase-conjugate mirror.]
> >
> >	Problem is, a powersat in geostationary orbit will be so far away that
> 				  ^^^^^^^^^^^^^
[Rest of my garbage deleted.]

> 	Yes, that had occurred to me, which is why I was specific to say
> an LEO station.  Such a station would have a number of receiving
> points on the ground.  Sorry for not being clearer about that point.

	Wow -- that was really stupid of me.  How could I mess up 1
abbreviation, especially after reading neuroscience articles with so many
abbreviations that you have to keep track of that it rivals the government?
Hmmm. . .hope that doesn't say something about how well I am going to do in
that course. . . .

> 	Alternatively, one could have one GEO powersat and one fixed
> receiving point on the ground, where the powersat excites an
> amplifying phase-conjugate mirror that is flying by at LEO.  

	I wonder how big a beam would you need so that it wouldn't be so
concentrated as to fry something flying through (we're not talking about misses
here, since presumably you could use conjugatable guide beams for the long leg
as well, as long as it didn't have to go through atmosphere), but about the
beams during normal use.  People assigning satellite orbits would have to worry
not only about objects (essentially small spheres of safety distance), but now
about laser beams (long cylinders of safety distance to keep out of).  This is
not a problem unique to what you propose, although having the powersats track
moving retransmitter satellites could complicate this problem, although how
big a powersat you can build in low earth orbit might be an overriding
consideration.  The same problem holds true for microwave transmission, except
that a laser beam can be considerably more concentrated (sizzle. . .).

-- 
	-- Lucius Chiaraviglio
	   lucius@tardis.harvard.edu
	   {insert your favorite brave system here}!seismo!tardis!lucius

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