Exploring the surface of Titan

The exploration of Saturn's giant satellite Titan is considered, with particular reference to its surface which is hidden beneath a thick atmosphere. Groundbased observations, in which great progress has been made recently, and the measurements made by the Pioneer and Voyager spacecraft, are reviewed. Concepts for spacecraft to perform in-situ measurements on Titan are reviewed, as is the development of the NASA/ESA Cassini mission, how the mission constrains scientific investigations, and in turn how the mission has been constrained by funding pressures. The capabilities of the Cassini payload for investigating Titan's surface are critically assessed, and the ability of the Surface Science Package (SSP) on the Huygens probe to determine the composition of surface liquids is examined. Some thoughts on payload selection and the value of individual measurements are presented.

The development of an impact penetrometer, and the interpretation of penetrometer and accelerometer data to measure surface mechanical properties, is described. It should be noted that Huygens is not a vehicle expressly designed as a lander, so the impact dynamics are complex. Additionally, the examination of the prospects offered by acoustic instrumentation are investigated.

Modelling of a number of Titan surface processes is presented, including rainfall, photochemical and meteoric deposition, tidal dissipation in the interior, regolith processes such as volatile heat transport, annealing and aeolian transportation and the effects of tidal and crustal processes on lakes.

A key subtopic of the thesis addresses the theme of planetary exploration as a whole, with the interaction between and the limitations of the exploration 'triad' of observations, insitu measurements and theory. Note is made of the remarkably significant role played by individuals and their perceptions.