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 tum 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
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.