GalileoThe mission of the unmanned space probe Galileo ends in the clouds of the giant planet Jupiter, which it has orbited for eight years. Even as Galileo plunges toward Jupiter, it detects and reports evidence of a thin ring sharing the orbit of the small moon Amalthea, and then disintegrates as it falls into Jupiter. NASA has opted to send Galileo to its destruction, rather than risking a collision with Europa, which may harbor some of the ingredients necessary for life and might be contaminated if Galileo impacted it; Galileo’s mission was extended three times, with the vehicle lasting six years longer than anticipated in the original mission plan’s estimates, which included for the harsh radiation environment of Jupiter as a factor in expecting only a two-year mission.