🚀 go-pugleaf

There's no need for the nuclear reactors to move Ceres.
You can use a much smaller asteroid to tranfer angular momentum & energy
between Ceres & (say) Vesta.  Ceres needs to be moved only enough to
either approach Mars, or a resonance with Jupiter; probably the resonance
is closer.  And, of course, the smaller asteroid could be manipulated
with a still smaller asteroid, etc.  The same scheme could be used to
eject Ganymede from its orbit around Jupiter, giving you a larger working
mass.  Of course, the tides from even a Ceres close approach might be
a problem:  Assuming Ceres's mass is 1/8 that of the moon, it would cause
equivalent tides at 1/2 the Lunar distance, ~ 30 Earth radii.  If it
passes at 1 Er, that's 27000 times the tidal force.  Could be fun to
watch, from a safe distance.

Wrt accurate gravity measurement & orbit prediction, I'd guess that the
uncertainty principle is the greatest problem; you can't know Ceres
position & velocity accurately enough to predict more than (say) 100
encounters ahead.  The steering rockets would have to be capable of
influence exceeding hbar; pea shooters would do.

Rich Schroeppel  rcs@cs.arizona.edu