PASADENA, Calif. (AP) - Galileo will make its closest flyby of Jupiter's volcanic moon Io this week as controllers race to put it through ever riskier maneuvers before the aging spacecraft conks out. Mission managers acknowledge the risks but say they want to make the most of what will likely be the spacecraft's final months. Galileo, circling the solar system's largest planet for more than four years, long ago exceeded expectations. On Tuesday, the 2-1/2-ton orbiter will fly within 124 miles of Io in a maneuver that will bombard the probe with immense radiation. Previous orbits near the fiery moon crippled Galileo's computer, though engineers managed to restart it each time. Galileo is tentatively scheduled to zoom by the moon Ganymede in May and December.