Gravity field of Jupiter and its satellite from Pioneer 10 and Pioneer 11 tracking data

Abstract

Accurate two-way Doppler tracking data obtained from Pioneers 10 and 11 during their Jupiter encounters are analyzed to yield significantly improved values for the masses of the Galilean satellites, the harmonic coefficients of Jupiter, and the mass of the planet. The spacecraft trajectories relative to Jupiter are discussed, and nongravitational spacecraft accelerations are taken into account. Gravity results are derived from a simultaneous iterative weighted least-squares solution for the orbital elements of seven bodies, the masses of Jupiter and the Galilean satellites, the right ascension and declination of Jupiter's instantaneous pole relative to the 1950.0 mean earth equator and equinox, the Jovian gravity harmonic coefficients, the mass of a hypothetical mascon at the Great Red Spot, and the nongravitational-acceleration parameters. Four separate solutions are determined, and the best numerical values are given for the ratios of the masses of the four Galilean satellites to the mass of Jupiter; the ratio of the sun's mass to that of the Jupiter system; the second, third, fourth, fifth, and sixth zonal harmonic coefficients of Jupiter; the sectoral harmonics; and the ratio of the hypothetical mascon's mass to that of Jupiter.