Extreme ecosystems have recently attracted considerable interest, not only because they prove that life is robust and adaptable, but also because their existence increases the probability of finding life elsewhere in the universe. Most of the best-characterised extreme habitats on Earth correspond to geophysical constraints (temperature, ionic strength, radiation, or pressure), to which opportunistic microorganisms have adapted. However, some extreme environments are unique in that they are the product of biological activity. Mars habitability studies can gain a tremendously from understanding biological conditions in terrestrial Mars analogues. Debate has long existed about the habitability of Mars and Europa and the possible existence of life in these planetary bodies. Future missions will need automated tools for astrobiological in situ studies and one major challenge will be the development of automated life detection systems. The best places on Earth for testing this instrumentation are extreme environments. In this session, we aim to bring together scientists from diverse disciplines such as engineering, geochemistry, extreme ecosystems microbiology and planetary science to discuss life in extreme ecosystems and the development of new tools for future space missions.