QUESTION: 
How does it feel to be looking at four other moons with a thought in
your head that says " We didn't walk on those yet?" [In reference to 
Jupiter's Moons]

ANSWER from Ted Dunham 16 October, 1995:
I don't really think very much about that.  It would be a lot easier to walk
on Mars, and we haven't done that either.  I think more about that issue.
Also, the radiation level on Io is so high that nobody in their right mind
would ever want to get near that place!