Goli, Marta ; Le Maistre, Sébastien ; Yseboodt, Marie ; Caldiero, Alfonso ; Dehant, Véronique

Poster presented at American Geophysical Union Fall Meeting 2023 on 2023-12-12

Abstract: The polar motion of Mars is defined as the movement of the rotation axis with respect to a fixed frame tied to the crust. Composed of annual, seasonal and free wobble periods, it provides information on the atmospheric dynamics and seasonal mass exchanges, as well as on the interior structure, making it an attractive study target for investigations using radiometric data. We investigate the uncertainties associated with Mars pole motion (PM) parameters estimation using Doppler, Range and Same-Beam Interferometry (SBI) observables between multiple landers on the surface of Mars and the Deep Space Network (DSN) on Earth. We use the MONTE astrodynamics and measurement simulation suite from JPL to evaluate the improvement enabled by combining data from multiple landers, identify the optimal mission architectures for PM estimation, and analyze them by considering the influence of respective mission parameters on the estimation uncertainty. In particular, we consider the effects of absolute and relative locations of the landers, observation scheduling considerations, and noise level. We re-evaluate the possibility of estimating the polar motion using data from landers in proximity to the equator, and apply our considerations to existing past, present and future missions such as InSight or the planned Mars Sample Return lander. We also consider the possible improvement in the estimation of the period of the pole’s free Chandler Wobble, which has recently been detected for the first time using orbiter radio tracking (Konopliv et al 2020).

Keyword(s): Mars ; Radio science ; Polar motion ; Simulations
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