Mars high resolution gravity fields from MRO, Mars seasonal gravity, and other dynamical parameters

Abstract

With 2 years of tracking data collection from the MRO spacecraft, there is noticeable improvement in the high frequency portion of the spherical harmonic Mars gravity field. The new JPL Mars gravity fields, MRO110B and MRO110B2, show resolution near degree 90. Additional years of MGS and Mars Odyssey tracking data result in improvement for the seasonal J ¯ 3 gravity changes which compares well to global circulation models and Odyssey neutron data and Mars rotation and precession ( ψ ˙ = - 7594 ± 10 mas / year ). Once atmospheric dust is accounted for in the spacecraft solar pressure model, solutions for Mars solar tide are consistent between data sets and show slightly larger values ( k 2 = 0.164 ± 0.009, after correction for atmospheric tide) compared to previous results, further constraining core models. An additional 4 years of Mars range data improves the Mars ephemeris, determines 21 asteroid masses and bounds solar mass loss ( dGM Sun / dt < 1.6 × 10 −13 GM Sun year −1).