Early (1970's era) Galileo end-of-mission options
Perhaps you are aware, but one of the early scenarios (ca. 1979) for the end of mission indeed had Galileo impacting (Ranger-style) onto Io. It was of course assumed that the HGA would be operational and could downlink imagery in real time. For the others who may not aware, the official recommendation by the National Academy of Sciences Space Studies Board for the termination of the Galileo Mission can be found at
http://www.nas.edu/ssb/galileoltr.htm
and their report on prevention of forward contamination of Europa at
http://www.nas.edu/ssb/europamenu.htm
Alex R. Blackwell
University of Hawaii