Dr Andrew Ball is a Postdoctoral Research Fellow at the Planetary and Space Sciences Research Institute at the Open University in Milton Keynes, UK. He works on planetary exploration, participating in a number of missions including Rosetta, Huygens and ExoMars. He is a Fellow of the Royal Astronomical Society and the British Interplanetary Society. James Garry is a Postdoctoral Research Scientist at the Leiden Institute of Chemistry, Leiden University, The Netherlands, and a Fellow of the Royal Astronomical Society. He has worked on ESA planetary missions for over ten years and has illustrated several space-related books. Ralph Lorenz is an Assistant Research Scientist at the Lunar and Planetary Laboratory, University of Arizona, USA. He is a Fellow of the Royal Astronomical Society and the British Interplanetary Society. He has 15 years of experience in NASA and ESA spaceflight projects and has authored several space books. Viktor Kerzhanovich is a Principal Member of Technical Staff of the Mobility and Robotic Systems Section of the Autonomous Systems Division, NASA Jet Propulsion Laboratory, USA. He was a participant of all Soviet planetary Venus and Mars entry probes.