An improved JPL Mars gravity field and orientation from Mars orbiter and lander tracking data

The Mars gravity field resolution is mostly determined by the lower altitude Mars Reconnaissance Orbiter (MRO) tracking data. With nearly four years of additional MRO and Mars Odyssey tracking data since the last JPL released gravity field MRO110C and lander tracking from the MER Opportunity Rover, the gravity field and orientation of Mars have been improved. The new field, MRO120D, extends the maximum spherical harmonic degree slightly to 120, improves the determination of the higher degree coefficients as demonstrated by improved correlation with topography and reduces the uncertainty in the corresponding Mars orientation parameters by up to a factor of two versus previously combined gravity and orientation solutions. The new precession solution is ψ˙=−7608.3±2.1mas/yr and is consistent with previous results but with a reduced uncertainty by 40%. The Love number solution, k2 = 0.169 ± 0.006, also shows a similar result to previous studies.