Interstellar Missions

[Abdul Ahad]

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_spaceagent/spaceprojects.html

[Christopher]

On 14 Jul 2003 11:32:28 -0700, (Abdul Ahad)
wrote:

>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...

>From what Ive read it'll be about half a light year, or I could have
got my interstellar probes mixed up.



Christopher
+++++++++++++++++++++++++
"Only those who risk going too far,
can know how far they can go."
T.S. Elliot

[Henry Spencer]

In article >,
Abdul Ahad > wrote:
>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?

Last I heard, the biggest uncertainty was simply poor knowledge of the
relative velocities of the stars (which are moving much faster than
Pioneer itself).

>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?

Not really, not unless you assume undiscovered dim stars near the path
(which is a possibility -- sky-survey missions like Hipparcos have had
limited sensitivity). Everything else is just too far away to make a
big difference on that time scale.
--
MOST launched 1015 EDT 30 June, separated 1046, | Henry Spencer
first ground-station pass 1651, all nominal! |

[Harmon Everett]

(Abdul Ahad) wrote in message >...
<snip>
>> 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.
There is some really good stuff around. Do a google search on "3d star maps"

Harmon