Interstellar Missions

When Pioneer 10 eventually passes Aldebaran - projected to be in
around 2 million years time (!), do we know how "close" the flyby is
likely to be...not that we'd be around to witness such an event of
course. How accurate are the [interstellar] dynamical considerations
in projecting these trajectories I wonder? I mean the gravity/mass
estimates of stars and their perturbing influences in the vicinity of
a spacecraft's trajectory projected across such vast interstellar
volumes of space... on journeys over millions of years ... surely adds
up to major inaccuracies in the computations?

Can someone recommend me a site on the web that has an applet of some
kind, a book, or other publication that gives a true 3D perspective of
our region of the Milky Way (the 'Orion Arm') say within a cubic
volume of space 100 x 100 x 100 light years centred on the Sun (Sol)
that then allows visualisation of interstellar flight of an unpowered
craft like the Pioneers or the Voyagers? I am looking for an accurate
model movable over time, that takes account of proper motions, Milky
Way rotation, latest parallax-based distance estimates, stellar mass
estimates, etc.

When Voaygers 1 and 2 eventually break free of our Sun's sphere of
influence and go beyond the NASA heliopause "expectations", which
galactic directions are they headed out to, and which star systems
could they fly past? What would be interesting is if any of these
were projected to go close to a narby sun-like system where
exo-planets have already been detected... the food for imaginations
and speculations could then prove endless to us all!

Abdul Ahad
http://uk.geocities.com/aa_spaceagen...eprojects.html