1. Department of Ecological and Biological Sciences, University of Tuscia, Viterbo, Italy.
2. Institute of Planetary Research, German Aerospace Center (DLR), Berlin, Germany.
3. Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA.
4. Institute of Aerospace Medicine, German Aerospace Center (DLR), Cologne, Germany.
5. Department of Earth Observation, Spanish Aerospace Research Establishment-INTA, Torrejón de Ardoz, Madrid, Spain.