Project Galileo at Jupiter

Abstract Galileo made a highly successful arrival at Jupiter on December 7, 1995. The Galileo Atmospheric Entry Probe transmitted the first-ever direct measurements of an outer planet to the Orbiter mothership for nearly one hour while descending to a pressure depth of 23 bar-far beyond the 10 bar mission requirement. After storing the Probe data onboard, the Orbiter performed an essentially perfect insertion burn to become the first spacecraft to orbit an outer planet. In mid-March 1996, the third and final burn of Galileo's 400N main engine will raise the perijove distance so that the Orbiter can survive the radiation dose accumulation for the subsequent eleven orbits. The new flight software providing the onboard editing, compression, and telemetry capabilities required to perform the Orbiter mision via the low-gain antenna will be uplinked in May preparatory to the first satellite encounter-Ganymede 1-on June 27. The second satellite encounter-Ganymede 2-occurs on September 6. This paper will summarize: 1) the Probe mission results both engineering and scientific, 2) the problems with the Orbiter tape recorder and its recovery,3)theOrbiterengineering operations including the loading and performance of the new flight software, and 4) early science results from the arrival and first two orbits and Ganymede encounters. Overall mission status and the forecast for the remainder of the Orbiter's two-year primary mission will also be provided.