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The Mars Express (MEX) mission has been successfully operated around Marssince 2004. Among many results, MEX has provided some of the most accurateastrometric data of the two Mars moons, Phobos and Deimos. In this work wepresent new ephemerides of Mars' moons benefitting from all previouslypublished astrometric data to the most recent MEX SRC data. All in all,observations from 1877 until 2018 and including spacecraft measurements fromMariner 9 to MEX were included. Assuming a homogeneous interior, we fittedPhobos' forced libration amplitude simultaneously with the Martian tidal k2/Qratio and the initial state of the moons. Our solution of the physicallibration 1.09 +/- 0.01 degrees deviates notably from the homogeneous solution.But considering the very low error bar, this may essentially suggest thenecessity to consider higher order harmonics, with an improved rotation model,in the future. While most data could be successfully fitted, we found adisagreement between the Mars Reconnaissance Orbiter and the Mars Expressastrometric data at the kilometer level probably associated with a biased phasecorrection. The present solution precision is expected at the level of a fewhundreds of meters for Phobos and several hundreds of meters for Deimos for thecoming years. The real accuracy of our new ephemerides will have to beconfirmed by confrontation with independent observational means.

Mars moon ephemerides after 14 years of Mars Express data