At http://pluto.jhuapl.edu/news_center/news/20121016.php, there is an interesting post about the challenge facing the New Horizons as to whether to allow the spacecraft to remain on the current trajectory which will take it between Pluto and the orbit of Charon, the closest in known moon of Pluto. Given that the current round-trip light time is 6 hrs 53 minutes, a decision to go for a bail-out fly-past must be taken some 10 days in advance of the actual fly-past.