Lee wrote:
How is it risky and expensive to park Galileo into a stable orbit around Jupiter as opposed to crashing it into the gas giant? Simply leave it in orbit around Jupiter for the next several decades...

Alex writes:
Did you even read the reports that I referenced?:

National Academies of Science Space Studies Board recommendation on the termination of the Galileo Mission at
http://www.nas.edu/ssb/galileoltr.htm

and their report on the prevention of forward contamination of Europa at
http://www.nas.edu/ssb/europamenu.htm

For the last time, Galileo does not have sufficient delta-V capability (either propulsive or by gravity assist) to be put into a "stable" orbit. In fact, at distances where the gravitational affects of Jupiter and the Galileans would not be significant, then solar perturbations would dominate.

"Risk" refers to planetary protection; "expense" refers to money, and if you are not aware, spacecraft hardware and operational capability actually do cost money.

Lee wrote:
...until our technology progresses to the point of us being a solar system bases civilization.

Alex writes:
You're looking at more than just "decades."

Alex R. Blackwell
University of Hawaii