The most critical events of the Galileo mission occur on Jupiter arrival day, December 7, 1995. In chronological order, these one-time events are: a 1,000 km altitude flyby of the innermost Galilean satellite Io, the 75-minute Atmospheric Entry Probe mission, and the Orbiter's Jupiter Orbit Insertion (JOI) maneuver. In addition, extensive, unique Orbiter science observations are planned because this is the only time Galileo will encounter Io, fly through the Io torus, and will be so close to Jupiter--three times closer than at any of the perijove passes in the orbital mission. All of these events occur in what will be by far the most intense radiation environment Galileo will ever see.
The focus of this Paper is the extraordinary preparations being made to maximize the reliability of the most critical events in order to ensure a successful Probe mission and Orbit Insertion while also gathering unique arrival day Orbiter science.
The Paper also provides a mission status report including the return of the asteroid Ida data and the Galileo direct line-of-sight observations of Comet Shoemaker-Levy fragments impacting Jupiter in July 1994.