4598 20200124113113.0 POSTER-2020-0025 Dehant, Véronique Lander Radioscience - Rotation of Mars and Positioning of the lander. 2019 2019-04-11 The Lander Radioscience (RISE on the NASA InSight 2018 mission and LaRa on the ESA-Roscosmos ExoMars2020 mission) experiments are designed to obtain coherent two-way Doppler measurements from the radio linkbetween a lander on Mars and the Earth over at least one Martian year. The Doppler measurements will be usedto determine the orientation and rotation of Mars in space (precession, nutations, and length-of-day variations).Depending on the location of LaRa on the surface, the polar motion of Mars could be measured as well. Theultimate objective is to obtain information on the Martian interior and about the sublimation/condensation cycleof atmospheric CO2.Besides, Lander Radioscience allows to accurately locate the lander shortly after landing. A precise estimate ofthe lander’s position improves the quality of the early science operations and allows high-resolution cameras fromspacecraft to correctly target the lander. ESA/ PRODEX/ PlanetInt ESA/PRODEX/LaRa NO Le Maistre, Sébastien Baland, Rose-Marie Karatekin, Ozgur Mitrovic, Michel Péters, Marie-Julie Rivoldini, Attilio Van Hoolst, Tim Yseboodt, Marie Folkner, William Josov, Alexander Banerdt, William Bruce EGU General Assembly, EGU2019, 7-19 April, 2019 in Vienna, Austria rose-marie.baland@observatoire.be https://meetingorganizer.copernicus.org/EGU2019/EGU2019-10772-1.pdf CPOSTER