1. Earth and Planets Laboratory, Carnegie Institution for Science, Washington, DC 20015
2. NASA Hubble Fellowship Program Sagan Fellow, NASA Hubble Fellowship Program, Space Telescope Science Institute, Baltimore, MD 21218
3. Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125
4. Department of Philosophy, University of Colorado Boulder, Boulder, CO 80309
5. Department of Chemistry, Howard University, Washington, DC 20059
6. Blue Marble Space Institute for Science, Seattle, WA 98104
7. Department of Astronomy, Cornell University, Ithaca, NY 14853
8. Cornell Center for Astrophysics and Planetary Science, Carl Sagan Institute, Cornell University, Ithaca, NY 14853