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From: ethan@utastro.UUCP (Ethan Vishniac)
Newsgroups: net.space
Subject: Re: Voyager, on to Uranus.
Message-ID: <464@utastro.UUCP>
Date: Thu, 1-Aug-85 11:19:15 EDT
Article-I.D.: utastro.464
Posted: Thu Aug  1 11:19:15 1985
Date-Received: Sat, 3-Aug-85 04:17:55 EDT
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Organization: U. Texas, Astronomy, Austin, TX
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> > 
> > Sorry Ethan, this is not entirely true.  While it is true that there is no
> > deliberate target, someone at JPL [sorry, forgot to copy his name down,
> > he deserves the credit] calculated the motions of local stars to 100,000
> > years.  Both Voyagers will pass to around 1 Light-year (approx) of the
> > star AC +79 3888 in about 40,000 years.  AC +79 3888 is currently 17
> > light years away and is expected to be about 3 light years away by that time.
> > [The velocity is left as an excercise to elementary school students...]. ;-)
> > After Neptune encounter of V 2, a decision will be made whether to use the
> > remaining manuveuring fuel to improve the current trajectory for a
> > closer encounter with AC +79 3888.
> > 
> > --eugene miya

Actually, something about this puzzles me.  Assuming that the space velocity
of AC +79 3888 is only known to within 1 km/sec I get that even we aimed
something at that star we would expect to miss by 13% of a light year.
This is about a trillion kilometers (about 8000 AU).  Admittedly there
may be no other use for the manuveuring fuel than aiming at AC +79 3888,
but no one could reasonably expect anyone there to notice it as it goes
by.  I'm not much on velocity determinations, but isn't this basically
right?
-- 

"Don't argue with a fool.      Ethan Vishniac
 Borrow his money."            {charm,ut-sally,ut-ngp,noao}!utastro!ethan
                               Department of Astronomy
                               University of Texas