1. Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
2. School of Physics and Astronomy, Cardiff University, 4 the Parade, Cardiff CF24 3AA, U.K.
3. Rufus Scientific, Melbourn, Royston, Herts SG8 6ED, U.K.
4. Department of Geosciences, University of South Florida, Tampa, Florida 33620, United States
5. Lunar & Planetary Laboratory/Department of Planetary Sciences, University of Arizona, Tucson, Arizona 85721-0092, United States
6. JJ Scientific, Warsaw 02-792, Poland
7. Department of Physics, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
8. Department of Aeronautics and Astronautics, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States