title: Interior structure and seasonal mass redistribution of Mars from radio tracking of Mars Pathfinder.
abstract: Doppler and range measurements to the Mars Pathfinder lander made using its radio communications system have been combined with similar measurements from the Viking landers to estimate improved values of the precession of Mars' pole of rotation and the variation in Mars' rotation rate. The observed precession of -7576 +/- 35 milliarc seconds of angle per year implies a dense core and constrains possible models of interior composition. The estimated annual variation in rotation is in good agreement with a model of seasonal mass exchange of carbon dioxide between the atmosphere and ice caps.
authors.affiliation: Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, USA. william.folkner@jp.nasa.gov
authors.forename: W M
authors.initials: WM
authors.lastname: Folkner
authors.forename: C F
authors.initials: CF
authors.lastname: Yoder
authors.forename: D N
authors.initials: DN
authors.lastname: Yuan
authors.forename: E M
authors.initials: EM
authors.lastname: Standish
authors.forename: R A
authors.initials: RA
authors.lastname: Preston
mesh_terms: D001272:Atmosphere; D002245:Carbon Dioxide; D005118:Extraterrestrial Environment; D005296:Ferrous Compounds; D007053:Ice; D007501:Iron; D018535:Mars; D011312:Pressure; D013696:Temperature
chemical_list: D005296:Ferrous Compounds; D007053:Ice; D002245:Carbon Dioxide; D007501:Iron; C022597:ferrous sulfide