: The Photopolarirneter/Radiometer (PPR) instrument aboard the Galileo spacecraft will go into orbit around Jupiter in December, 1995. The 23 month tour offers PPR Gan ymede encounters, three encounters, and Europa encounters with maximum PPR resolution varying from 0.5 ktn to km and typical resolution of 200 km. In addition, will be one Ganymede, one and two Europa `non-targeted' encounters giving maximum resolution from 58 km to 200 km with a typical resolution of 300 km. There is single encounter before Jupiter orbit insertion that will provide resolutions ranging from 400 km to 2.5 km, and numerous subsequent to observe with resolution as good as 600 km. The PPR will be used to study the polarization of reflected sunlight from each satellite over a range of phase angles. It will also map daytime and nighttime surface temperatures to look for spatial variations in properties, study volcanic activity on and look for possible thermal activity on Europa. These observation plans are p..