The gravity field of Mars

Abstract

A complete sixth‐degree spherical‐harmonic model of the gravitational potential of Mars has been produced from an analysis of Doppler data obtained from the radio tracking of the Mariner‐9 spacecraft for over 200 orbital revolutions. The equipotential surface defined by this model is estimated to be accurate to within 100 m below 60° North Latitude and to within 300 m above. The dominant feature of this surface is a Tharsis‐related bulge which rises nearly two kilometers above the surrounding areas. Gravitational “lows” are found to correspond to the Hellas depression and the Valles Marineris.