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Deriving Mercury geodetic parameters with altimetric crossovers from the Mercury Laser Altimeter (MLA)
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  • Stefano Bertone,
  • Erwan Mazarico,
  • Michael Barker,
  • Sander Goossens,
  • Terence Sabaka,
  • Gregory Neumann,
  • David E Smith
Stefano Bertone
University of Maryland Baltimore County

Corresponding Author:[email protected]

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Erwan Mazarico
NASA Goddard Space Flight Center
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Michael Barker
NASA Goddard Space Flight Center
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Sander Goossens
University of Maryland Baltimore County
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Terence Sabaka
NASA Goddard Space Flight Center
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Gregory Neumann
NASA Goddard Space Flight Center
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David E Smith
Massachusetts Institute of Technology
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Abstract

Based on previous applications of laser altimetry to planetary geodesy at GSFC, we use the recently developed PyXover software package to analyze altimetric crossovers from the Mercury Laser Altimeter (MLA). Using PyXover, we place new constraints on Mercury’s geodetic parameters via least‐squares minimization of crossover discrepancies. We simultaneously solve for orbital corrections for each MLA ground track, for the geodetic parameters of the IAU‐recommended orientation model for Mercury (pole right‐ascension and declination coordinates, prime meridian rotation rate and librations), and for the Mercury’s Love number h2. We calibrate the formal errors of our solution based on closed‐loop simulations and on the level of robustness against a priori values, data selection, and parametrization. Our solution of the Mercury’s rotational parameters is consistent with published values. In particular, our new estimate for the orientation of the pole places Mercury in a Cassini state, with an obliquity ϵ = 2.031 ± 0.03 arcmin compatible with previous “surface” related measurements. Moreover, we provide a first data‐based estimate of the Love number h2 = 1.55 ± 0.65. The latter is consistent with expectations from models of Mercury’s interior, although its precision does not enable their refinement.
Apr 2021Published in Journal of Geophysical Research: Planets volume 126 issue 4. 10.1029/2020JE006683