1. California Institute of Technology, Department of Geologic and Planetary Sciences, Pasadena, Califor
2. University of Copenhagen, Niels Bohr Institute, Copenhagen
3. Johns Hopkins University Applied Physics Laboratory, Laurel, Maryland
4. Western Washington University, Geology Department, Physics and Astronomy Department, Bellingham, Was
5. NASA Jet Propulsion Laboratory, La Cañada, California
6. Arizona State University, School of Earth and Space Exploration, Tempe, Arizona