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...Bills et al rotational dynamics of europa bruce g nasa goddard space flight center and scripps institution oceanography francis nimmo university california santa cruz ozgur karatekin tim van hoolst nicolas rambaux royal observatory belgium benjamin levrard institut de mecanique celeste calcul des ephemerides ecole normale superieure lyon jacques laskar the state is only rather poorly constrained at present it known to rotate about an axis that nearly perpendicular orbit plane a rate constant approximates mean orbital small departures from rotation os cillations both lead stresses may influence location orienta tion surface tectonic features however geological evidence for either these processes disputed we describe variety issues future geodetic observations will likely resolve including variations in direction on wide range timescales since external perturbations causing changes are generally well amplitude phase responses provide important information internal structure focus three a...