Post by Dr. Stéphane Le Mouélic, Laboratoire de Planétologie et Géodynamique, CNRS UMR6112- University of Nantes, Nantes, France.

Titan is one of the most fascinating bodies of our Solar System. Bigger than Mercury, this satellite of Saturn is veiled by a thick atmosphere of nitrogen containing a few percent of methane. Aerosols formed in the atmosphere by a complex chemistry triggered by the solar UV irradiation produce a global haze totally masking the surface to the naked eye. During 13 years, from July 2004 to September 2017, the Cassini spacecraft orbited Saturn. It took advantage of gravity assist maneuvers to perform 127 equatorial and polar flybys of Titan. Data from the Visual and Infrared Mapping Spectrometer (VIMS) onboard Cassini revealed the distribution of the main compositional units of the surface of Titan (Image 1). The inset in Image 1 shows the 84 km-diameter Selk crater, one of the primary targets chosen for the next New Frontier “Dragonfly” mission, a mobile rotorcraft-lander planned to be launched in 2026.

Image 1: False color composite of Titan with the red controlled by the 1.59/1.27 µm, green by the 2.03/1.27 µm and blue by the 1.27/1.08 µm band ratios. The equatorial dune fields appear in a consistent brown color. Selk crater is shown in the inset. Credits NASA/JPL/Univ. Arizona/CNRS/LPG.

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