

I can't see the need for a single (big? expensive? heavy?) "mothership" except
for Voyager style flyby missions. A few years ago, I did some calculations on a
"Grand Tour" space probe launched by a Saturn V in 1975-76. At the time,I felt 
that
the idea of a big "mother ship" had some merit - the Voyagers had to be rather
small, lightweight craft due to the limitations imposed by using weak Titan
III/Centaur launchers. The concept I examined (and Michael's?) had a lot in
common with the British Interplanetary Society's Daedalus project for sending a
probe to Barnard's Star - i.e. a large "bus" spacecraft carrying several
smaller probes to be dispatched when the ship arrives at its destination.
The Saturn V supposedly would have been able to launch a 10-ton payload towards
Jupiter and beyond. The "bus" could have included far more powerful
cameras/telescopes/scientific equipment and a heavier/more powerful power
source than the Voyagers as there would be no limitations on weight anymore.
Extremely important as the Voyagers had to perform most of their measurements
within a couple of weeks before and after planetary encounter, and usually at a
relatively great distance.
---
The smaller probes carried aboard might have been based on the "real" Voyagers,
and an even smaller version like the one scheduled for launch towards Pluto in
the early 21st century, and would have been released at various points during
the mission. The advantages are obvious: the bus would have carried out the
same basic Jupiter-Saturn-Uranus-Neptune mission than Voyager 2 did, but in
addition two "sub-probes" could have been relased at Saturn, examining
that planet's south polar regions before moving on to Pluto. This would have
enabled NASA to map both hemispheres of Pluto/Charon by 1986...and several
other probes could have examined parts of the Jupiter/Saturn/Uranus/Neptune
systems that weren't examined in great detail by the Voyagers due to
trajectory-related factors. A small "swarm" of camera-equipped miniature space
probes released a month before encounter would have been too costly for a 
small Voyager-type mission but entirely feasible if launched from a heavy, 
well-equipped spacecraft. And would we have learned a lot more about the outer
planets! The reason why the Grand Tour was cancelled was lack of money, of
course. 

MARCU$