Introduction to the Galileo special section

Abstract

In December 1990 the Galileo spacecraft encountered the Earth‐Moon system in the first of two flybys that are part of a sequence of planetary gravity assists that will deliver the spacecraft to Jupiter in 1995. The geometry of the first lunar flyby was particularly fortuitous in that the western near side and portions of the far side of the Moon were illuminated, a condition not available during the Apollo missions because of the constraints on illumination during landing and surface operations. The Solid State Imaging System on board the Galileo spacecraft was thus able to obtain the first spacecraft multispectral images of the Moon since Mariner 10 snapped a few vidicon images on its way by the Moon to Venus and Mercury in 1973. These images provided very important new data on the characteristics of the Moon on the western near‐side limb, in the area of the Orientale basin, and on the far side, particularly in the region of the gigantic South Pole‐Aitken basin [Belton et al., 1992].