Original Article

Celestial Mechanics and Dynamical Astronomy

, Volume 107, Issue 1, pp 285-298

First online:

Light-time computations for the BepiColombo Radio Science Experiment

  • G. TommeiAffiliated withDepartment of Mathematics, University of Pisa Email author 
  • , A. MilaniAffiliated withDepartment of Mathematics, University of Pisa
  • , D. VokrouhlickýAffiliated withInstitute of Astronomy, Charles University

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The Radio Science Experiment is one of the on board experiments of the Mercury ESA mission BepiColombo that will be launched in 2014. The goals of the experiment are to determine the gravity field of Mercury and its rotation state, to determine the orbit of Mercury, to constrain the possible theories of gravitation (for example by determining the post-Newtonian parameters), to provide the spacecraft position for geodesy experiments and to contribute to planetary ephemerides improvement. This is possible thanks to a new technology which allows to reach great accuracies in the observables range and range rate; it is well known that a similar level of accuracy requires studying a suitable model taking into account numerous relativistic effects. In this paper we deal with the modelling of the space-time coordinate transformations needed for the light-time computations and the numerical methods adopted to avoid rounding-off errors in such computations.


Mercury Interplanetary tracking Light-time Relativistic effects Range Range rate Shapiro effect