ARCHITECTURE. K.H. Baines, S. K. Atreya , D. Crisp, J. L. Hall, V. V. Kerzhanovich, S. S. Limaye, K. Zahnle, Jet Propulsion Laboratory (MS 183-601, 4800 Oak Grove Dr., Pasadena, CA 91109; kevin.baines@jpl.nasa.gov), 2 University of Michigan, Dept of Atmospheric, Oceanic, and Space Sciences (2455 Hayward St., Ann Arbor, MI 48109), Jet Propulsion Laboratory (MS 183-501, 4800 Oak Grove Dr., Pasadena, CA 91109), Jet Propulsion Laboratory (MS 82-105, 4800 Oak Grove Dr., Pasadena, CA 91109), Jet Propulsion Laboratory (MS 198-219, 4800 Oak Grove Dr., Pasadena, CA 91109), University of Wisconsin-Madison, Space Science and Engineering Center (1226 West Dayton St., Madison, WI 53706), NASA/Ames Research Center (M/S 245-3, Moffett Field, CA 94035).