Titan's Surface Seen by VIMS/Cassini

On October 26th 2004, the Cassini spacecraft will fly over Titan at a distance of 1000 km at closest approach. The Visual and Infrared Mapping Spectrometer (VIMS) will observe Titan during more than 20 hours. More than 100 hyperspectral images should be recorded with spatial resolution ranging from 100 km to 1 km at closest approach. The images will include views of the Huygens landing site (10S, 190W) with a spatial resolution of 20 km and it should provide a context map for the probe that will land there in January 2005. During Saturn Orbit Insertion, the first observations of Titan by VIMS prove how well this instrument can see Titan's surface in several infrared windows at 1.3, 1.6, 2, and 5 µm. These observations should allow us to map tectonic features and morphological features such as impact craters. Titan's large eccentricity (0.03) may be responsible for the presence of large cracks at its surface as is the case for Europa. It will be possible to compare Titan's surface with that of other large satellites Ganymede, Callisto, and Europa. A major issue concerns the source of methane in Titan's atmosphere : oceans, subsurface reservoirs or cryo-volcanism. The data should allow us to determine whether an ocean is present at Titan's surface. Moreover, analyses of these data should help us determine the surface composition and its variations with latitude and longitude.