Research by Lorenz, R D, Lunine, J I , Beauchamp, P: APL, LPL, JPL, NASA

Radar images of hydrocarbon lakes on Titan.

Titan has been long known to be a photochemical factory: photolysis of methane in its nitrogen-rich atmosphere yields an impressive inventory of nitriles and hydrocarbons. These may be processed further on the surface by occasional transient exposure of these materials to liquid water (impact melt sheets and cryovolcanism).

In reviewing data from the Cassini spacecraft and the Huygens Probe, scientists indicated that an organic-rich surface with a diversity of surface textures and composition exists on the surface of Titan.

In addition, the Huygens probe data indicate the presence of heavy organics (including benzene) in the surface material at the landing site. The scientists also conclude that cryovolcanic activity is present, suggesting that the aqueous modification of nitriles to astrobiologically-important compounds such as amino acids, pyrimidines etc. may be extensive.

Implications

Understanding the details of the surface composition, which is challenging from orbit, begs for a future in-situ mission. A prominent concept for future Titan exploration is an airship or balloon which could drift or be driven slowly across Titan's varied, Earth-like landscape.

Artist's concept of Huygen lander on Titan's surface. (credit: ESA)

Significance to Solar System Exploration

Science goals that such a future mission to Titan could address include the sources of methane on Titan, the origin of its atmosphere, and its evolution through time. Techniques to be used by such a mission include: High- resolution imaging for geomorphology, subsurface sounding by radar and in-situ sampling of surface material for analysis of organic composition. More could be learned in the area of atmospheric science. How? With an airborne platform, surface samples could be acquired from a variety of locations with different degrees and types of surface processing (fluvial sediments, sand dunes, cryovolcanic flows or impact ejecta blankets). All of these factors would lead us to a more thorough understanding of this mysterious moon and its unique characteristics.

Last Updated: 3 February 2011