 Galileo 's trajectory carried it into the asteroid belt twice on its way to Jupiter . During its second crossing , it flew by Ida on 28 August 1993 at a speed of 12 @,@ 400 m / s ( 41 @,@ 000 ft / s ) relative to the asteroid . The onboard imager observed Ida from a distance of 240 @,@ 350 km ( 149 @,@ 350 mi ) to its closest approach of 2 @,@ 390 km ( 1 @,@ 490 mi ) . Ida was the second asteroid , after Gaspra , to be imaged by a spacecraft . About 95 % of Ida 's surface came into view of the probe during the flyby . 
