It was intended to study the ionizing radiation, cosmic rays, magnetic fields, and micrometeorites in the vicinity of the Earth and in lunar orbit. Due to a launch vehicle malfunction, the spacecraft attained only a ballistic trajectory and never reached the Moon.
Second Jupiter flyby. Used Jupiter's mass in a gravity assist to alter its trajectory toward Saturn. Made a successful Saturn flyby and then followed an escape trajectory from the solar system. On Dec. 4, 1974, Pioneer 11 passed to within 34,000 km of Jupiter's cloud tops and obtained dramatic images of the Great Red Spot, made the first observation of the immense polar regions, and determined the mass of Jupiter's moon Callisto.