Stephane Le Mouelic, LPGN Laboratoire de Planétologie et Géodynamique de Nantes, Nantes Cedex 03, France, Benoit Seignovert, NASA Jet Propulsion Laboratory, Pasadena, United States, Sebastien Rodriguez, AIM - CEA/CNRS/Uni. P7, Gif/Yvette, France, Thomas Cornet, CEA, Gif sur Yvette, France, Christophe Sotin, NASA Jet Propulsion Laboratory, Pasadena, CA, United States, Jason W Barnes, University of Idaho, Moscow, ID, United States, Robert Hamilton Brown, Univ Arizona, Tucson, AZ, United States and Roger Nelson Clark, USGS, Denver, CO, United States