1. Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder 80309
2. Division of Geophysics and Planetary Science, California Institute of Technology, Pasadena 91125
3. NASA Ames Research Center, Moffett Field, California 94035
4. Earth and Space Science Institute, University of Southern California, Tucson, Arizona 85767
5. Jet Propulsion Laboratory, Pasadena, California 91109
6. Astronomy Department and Mathematics Department, University of California, Berkeley 94720
7. Center for Radar Astronomy, Stanford University, Stanford, California 94305