Geodesy constraints on the interior structure and composition of Mars

► Geodesy data constrain the interior structure and composition of Mars. ► Geodesy data imply that Mars has no inner core. ► The radius of the liquid core is 1794 ± 65 km. ► The core sulfur concentration is 16 ± 2 wt% if sulfur is the only light element in the core. ► Interior structure models with a chondritic Fe/Si ratio are consistent with the data.