Pioneer 11 significant event planetary flyby
Encounter with Jupiter
Pioneer 11 flew past Jupiter in November and December 1974. During its closest approach, on December 2, it passed 42,828 kilometers (26,612 mi) above the cloud tops. The probe obtained detailed images of the Great Red Spot, transmitted the first images of the immense polar regions, and determined the mass of Jupiter's moon Callisto. Using the gravitational pull of Jupiter, a gravity assist was used to alter the trajectory of the probe towards Saturn and gain velocity. On April 16, 1975, following the Jupiter encounter, the micrometeoroid detector was turned off.