NASA's Cassini spacecraft observations of the moon on Aug. 19, 1999 show
water and hydroxyl at all latitudes on the surface, even areas exposed to
direct sunlight. The Visual and Infrared Mapping Spectrometer (VIMS)
instrument on Cassini made the observations as the spacecraft flew by the
moon. Its view was slightly south of the lunar equator. The yellow cross
indicates a latitude and longitude of zero.
The picture at top left shows infrared light reflected off the moon as
seen by VIMS. The top right picture shows the moon as seen by Cassini's
Imaging Science Sub-system (ISS) during the flyby. The image at bottom
left shows temperatures of the moon derived from VIMS data. Temperatures
near the equator are hotter than boiling water on Earth. The bottom center
picture shows a VIMS map of water associated with minerals. At bottom
right is a VIMS map of hydroxyl-bearing minerals, created by chemical
reactions with minerals and glasses in the lunar soil.