Xref: utzoo sci.astro:3362 sci.space:9321
Path: utzoo!attcan!uunet!lll-winken!ames!ucsd!sdcsvax!ucsdhub!hp-sdd!hplabs!hplabsb!dsmith
From: dsmith@hplabsb.HP.COM (David Smith)
Newsgroups: sci.astro,sci.space
Subject: Re: Finding Lagrange's Libration Points
Message-ID: <5125@hplabsb.HP.COM>
Date: 26 Jan 89 20:20:36 GMT
References: <1989Jan18.044744.18328@sq.uucp> <11854@dartvax.Dartmouth.EDU>
Reply-To: dsmith@hplabsb.UUCP (David Smith)
Organization: Hewlett-Packard Labs, Palo Alto, CA
Lines: 14

In article <11854@dartvax.Dartmouth.EDU> dalex@eleazar.dartmouth.edu (Dave Alexander) writes:
>So if L1, L2, and L3 are loci of unstable equilibrium, how can we expect
>an object to librate or oscillate about any of them?

I didn't work through the mathematics, but:
In an article on ISEE, Aviation Week pointed out that L1 was at a saddle
point.  The spacecraft was attracted to the Earth-Sun line, orbiting it.
In the direction of the line, position was unstable, but quite manageable
to the fuel budget.
-- 

			David R. Smith, HP Labs
			dsmith@hplabs.hp.com
			(415) 857-7898