1. Department of Geological Sciences, Brown University, Providence, Rhode Island 02912
2. McDonnell Center for the Space Sciences, Department of Earth and Planetary Sciences, Washington University, St. Louis, Missouri 63130
3. Martin Marietta Corporation, Denver, Colorado 80201
4. Institut für Geophysik, University of Kiel, Federal Republic of Germany, and Science Applications, Inc., Pasadena, California 91101
5. Laboratory for Planetary Studies, Cornell University, Ithaca, New York 14853
6. NASA Langley Research Center, Hampton, Virginia 23665
7. Center for Earth and Planetary Physics, Harvard University, Cambridge, Massachusetts 02138
8. Department of Genetics, School of Medicine, Stanford University, Stanford, California 94305
9. U.S. Geological Survey, Flagstaff Arizona 86001
10. NASA Ames Research Center, Moffett Field, California 94305
11. Jet Propulsion Laboratory, Pasadena, California 91103