Exploring Mars and its terrestrial analogues
Flamini, Enrico ; Ori, Gian Gabriele ; di Pippo, Simonetta ; et al.
May - 2009
DOI: 10.1016/j.pss.2009.02.004
ISSN : 00320633 ;
journal : Planetary and Space Science

Issue : 5-6
type: Article Journal

Analogy is defined as “a similarity between like features of two things, on which a comparison may be based or, in other words, a form of reasoning in which one thing is inferred to be similar to another thing in a certain respect, on the basis of the known similarity between the things in other respects”. This is what can be found in a dictionary. In space exploration, analogues have been used since the very beginning for the interpretation of the morphological features that were observed on images transmitted by spacecraft back on Earth. The interpretation of those images obliged the start of a strong exchange of knowledge between different fields of science, in particular geology and astrophysics, but also astrobiology, contributing to the formation of a new science: planetology. Since then the growing importance of the study and the use of terrestrial analogues for various space environments has become increasingly important with the in situ exploration and the increased capabilities of the landed elements. Nowadays we can rove around Mars and perform in situ analyses and, very likely in a short time, we will walk again on the Moon. Scientists may access a large amount of data including high resolution, colour and stereo images providing the capability of geological interpretation augmented by the landers providing tremendous in situ data. The use of the analogy of the Earths geological features has become a powerful tool to support and complement the understanding of remote sensing and in situ measurements and, at the same time, the processes acting on Earth are now investigated under a new “Planetary Light”. In addition, despite many efforts, no laboratory is capable of replicating a real planetary environment and it is fundamental that we rely on the long experience gained in centuries on Earth in order to extrapolate the models to explain observed phenomena on other planets. This also implies that the learning process, leading to properly operating a robot remotely on another planet, requires extensive experience. Such an experience can only be acquired using field testing in areas where the terrain, morphology and soil characteristics are as similar as possible to the ones expected on the planet to be explored. Then, we can say that analogues have a double valence: a living laboratory where geological and geophysical phenomena can be studied to support the interpretation of exotic data and a test facility where engineering aspects can be fully tested, operations can be optimised, and ground teams trained. But a candidate analogue site necessitates a long and detailed analysis before being “qualified” as such. One must take into account the fact that the Earth has a biosphere with a strong modification induced by humans. Several of the space nations have already developed specific experience in this field, but now new countries are entering the game. The combination of the experiences and ideas has become essential for the design of any exploration programme. This is the main reason why the Italian Space Agency, with the scientific support of IRSPS, organised in 2003, the first international conference on terrestrial analogues in Catania, Italy, in the vicinity of the Etna the largest European volcano; and then with the Canadian Space Agency, which shares similar experience and sensitivity for this subject, the second workshop in Trento in the frame of an agreement to hold jointly such conferences every two years alternatively in the two countries. The Trento conference was well attended with participants from all the continents and a large amount of high-quality papers were presented suggesting to the conveners the benefit to collect in dedicated publication the most significant. The reader will find in this special publication of Planetary Space Science papers addressing the various aspects of the role that terrestrial analogues currently play for the ongoing Martian missions and the preparation of the new missions. It may also be noted that although Mars has the higher relevance in this field, the Moon and the much more exotic world of Titan may benefit from the use of the study of terrestrial analogues.

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