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, or however long it takes, until our technology progresses to the point of us being a solar system bases civilization. Then we simply pick it up and bring it home. These probes can serve as time capsules to show future generations what we were capable of doing. Like artifacts brought up from the ocean floor, secure in their watery graves until our technology advanced to the point of retrieving them.