R. Carlson, ^* W. Smythe, K. Baines, E. Barbinis, K. Becker, R. Burns, S. Calcutt, W. Calvin, R. Clark, G. Danielson, A. Davies, P. Drossart, T. Encrenaz, F. Fanale, J. Granahan, G. Hansen, P. Herrera, C. Hibbitts, J. Hui, P. Irwin, T. Johnson, L. Kamp, H. Kieffer, F. Leader, E. Lellouch, R. Lopes-Gautier, D. Matson, T. McCord, R. Mehlman, A. Ocampo, G. Orton, M. Roos-Serote, M. Segura, J. Shirley, L. Soderblom, A. Stevenson, F. Taylor, J. Torson, A. Weir, P. Weissman

The Near Infrared Mapping Spectrometer performed spectral studies of Jupiter and the Galilean satellites during the June 1996 perijove pass of the Galileo spacecraft. Spectra for a 5-micrometer hot spot on Jupiter are consistent with the absence of a significant water cloud above 8 bars and with a depletion of water compared to that predicted for solar composition, corroborating results from the Galileo probe. Great Red Spot (GRS) spectral images show that parts of this feature extend upward to 240 millibars, although considerable altitude-dependent structure is found within it. A ring of dense clouds surrounds the GRS and is lower than it by 3 to 7 kilometers. Spectra of Callisto and Ganymede reveal a feature at 4.25 micrometers, attributed to the presence of hydrated minerals or possibly carbon dioxide on their surfaces. Spectra of Europa's high latitudes imply that fine-grained water frost overlies larger grains. Several active volcanic regions were found on Io, with temperatures of 420 to 620 kelvin and projected areas of 5 to 70 square kilometers.

R. Carlson, W. Smythe, K. Baines, R. Burns, A. Davies, P. Herrera, J. Hui, T. Johnson, L. Kamp, R. Lopes-Gautier, D. Matson, A. Ocampo, G. Orton, M. Segura, J. Shirley, A. Stevenson, P. Weissman, Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA.
E. Barbinis, F. Leader, R. Mehlman, Institute of Geophysics and Planetary Physics, University of California, Los Angeles, CA 90095, USA.
S. Calcutt, P. Irwin, F. Taylor, A. Weir, Department of Atmospheric, Oceanic, and Planetary Physics, Oxford University, Oxford OX1 3PU, UK.
K. Becker, W. Calvin, H. Kieffer, L. Soderblom, J. Torson, U.S. Geological Survey, Flagstaff, AZ 86001, USA.
R. Clark, U.S. Geological Survey, Denver, CO 80225, USA.
G. Danielson, Division of Geological and Planetary Science, California Institute of Technology, Pasadena, CA 91125, USA.
P. Drossart, T. Encrenaz, E. Lellouch, M. Roos-Serote, Observatoire de Paris, Meudon 92150, France.
F. Fanale, J. Granahan, G. Hansen, C. Hibbitts, T. McCord, Hawaii Institute of Geophysics and Planetology, University of Hawaii, Honolulu, HI 96822, USA.
^*   To whom correspondence should be addressed.

   Also at SETS Technology, Inc., Mililani, HI 96789, USA.