Gravity field of the Jovian system from Pioneer and Voyager tracking data

Data sets from the Voyager and Pioneer flybys of Jupiter and the Galilean satellites are employed to characterize the Jovian magnetic field and the effects of the Io torus on transmissions. Both optical and Doppler radio data are considered, except for periods when the Jovian radiation environment disturbed the oscillator stability of the radio transmitters. Account is taken of small accelerations of the spacecraft by tidal forces of a single rising satellite, density differences in the Great Red Spot producing a columnar gravitational change, and three unknown objects in the inner Jovian system. Correction parameters are developed for the effects on the S-band data induced by the Jovian plasmasphere inwards from the Io torus. Calculations are then made of the planet and satellite masses, gravity harmonic coefficients, and orientation of the rotational pole. Large reductions in the uncertainties in previous mass estimates are obtained.