The radioscience LaRa instrument onboard ExoMars 2020 to investigate the rotation and interior of Mars
Véronique Dehant, Sébastien Le Maistre, Rose-Marie Baland, Nicolas Bergeot, Ozgur Karatekin, Marie-Julie Peters, Attilio Rivoldini, Luca Ruiz Lozano, Orkun Temel, Tim Van Hoolst, Marie Yseboodt, Michel Mitrovic, Alexander Kosov, Václav Valenta, Leonid Gurvits, Jean-Charles Marty, Sami Asmar, William Folkner, the LaRa Team
(Submitted on 9 Oct 2019)
LaRa (Lander Radioscience) is an experiment on the ExoMars 2020 mission that uses the Doppler shift on the radio link due to the motion of the ExoMars platform tied to the surface of Mars with respect to the Earth ground stations (e.g. the deep space network stations of NASA), in order to precisely measure the relative velocity of the lander on Mars with respect to the Earth. The LaRa measurements shall improve the understanding of the structure and processes in the deep interior of Mars by obtaining the rotation and orientation of Mars with a better precision compared to the previous missions. In this paper, we provide the analysis done until now for the best realization of these objectives. We explain the geophysical observation that will be reached with LaRa (Length-of-day variations, precession, nutation, and possibly polar motion). We develop the experiment set up, which includes the ground stations on Earth (so-called ground segment). We describe the instrument, i.e. the transponder and its three antennas. We further detail the link budget and the expected noise level that will be reached. Finally, we detail the expected results, which encompasses the explanation of how we shall determine Mars’ orientation parameters, and the way we shall deduce Mars’ interior structure and Mars’ atmosphere from them. Lastly, we explain briefly how we will be able to determine the Surface platform position.
Comments: 43 pages, 39 figures, accepted in Planetary and Space Science
Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Instrumentation and Methods for Astrophysics (astro-ph.IM)
Cite as: arXiv:1910.03899 [astro-ph.EP] (or arXiv:1910.03899v1 [astro-ph.EP] for this version)
Submission history
From: Marie Yseboodt
[v1] Wed, 9 Oct 2019 11:12:02 UTC (4,962 KB)
