Encyclopedia of the Solar System

Tilman Spohn is director of the Institute of Planetary Research of the German Aerospace Center (DLR) in Berlin, Germany and Professor of Planetology at theWestfa?lische Wilhelms-University Mu?nster, Germany. He specializes in the Thermodynamics of Planetary Interiors and in physical problems of Astrobiology and has written 140 papers for scientific journals and books. He is a Principal Investigator (PI) for MUPUS on the Rosetta Lander Philae, for BELA on BepiColombo, and the instrument PI for HP3 on the InSight mission. Spohn has served as member and chairperson of ESA scientific working and advisory groups and is presently a member of ESA's HISPAC. He is the chairman of the science committee of the international Space Science Institute and has served as editor for Earth and Planetary Science Letters, Reviews of Geophysics, and the Treatise on Geophysics. He is the recipient of the 2013 EGU Runcorn-Florensky Medal and a fellow of the American Geophysical Union. Doris Breuer is Head of the Department of Planetary Physics at the Institute of Planetary Research of the German Aerospace Center (DLR) in Berlin, Germany and an Associate Professor at the Institute de Physique du Globe de Paris, France. She specializes in the interior dynamics, thermo-chemical evolution and interior structure of terrestrial bodies. She has published over 60 articles in refereed journals, has been coinvestigator on ESA's BepiColombo mission and has served on several ESA science definition teams and on the ESA Solar System Working Group. Torrence V. Johnson is a specialist on icy satellites in the solar system. He has written over 130 publications for scientific journals. He received a Ph.D. in planetary science from the California Institute of Technology and is now the Chief Scientist for Solar System Exploration at the Jet Propulsion Laboratory. He was the Project Scientist for the Galileo mission and is currently an investigator on the Cassini mission. He is the recipient of two NASA Exceptional Scientific Achievement Medals and the NASA Outstanding Leadership Medal and has an honorary doctorate from the University of Padua, where Galileo made his first observations of the solar system.