Above is the best yet color image of the asteroid Gaspra based on data returned by NASA's Galileo spacecraft. Color variations have been added to high resolution images and enhanced to highlight changes in reflectivity, surface structure and composition. The illuminated portion of the asteroid is about 11 miles long. Galileo encountered Gaspra on October 29, 1991 during the cruise phase of its mission to study the Jovian system. When it arrives at Jupiter, in December 1995, the robot spacecraft's atmospheric probe will descend into Jupiter's atmosphere, becoming the first ever probe to enter the atmosphere of a gas giant planet. Updates on Galileo's progress can be found at "Online from Jupiter".