1. Lunar and Planetary Laboratory; University of Arizona; Tucson AZ USA
2. Southwest Research Institute; Boulder CO USA
3. Department of Earth, Environmental and Planetary Sciences; Brown University; Providence RI USA
4. Department of Earth, Atmospheric and Planetary Sciences; Massachusetts Institute of Technology; Cambridge MA USA
5. Lamont-Doherty Earth Observatory; Columbia University; Palisades NY USA
6. Department of Terrestrial Magnetism; Carnegie Institution of Washington; Washington DC USA