Abstract

The exploration of the solar system in search for life, or for favorable conditions for the emergence and maintenance of life in a given environment, has in the past focused mainly on the terrestrial planets, Mars and Venus, our neighbors. I will present current and future space exploration of these planets, especially future exploration of Venus with the upcoming ESA and NASA missions Envision, Veritas and DaVinci, as well as on and around Mars with recent orbiters (TGO, Hope) and combined with landers (Mars 2020, Tianwen-1, etc) as well as future plans that aim to return samples from Mars and its satellites to Earth sometime in the 30s. However, in recent times, the habitable zone has been extended to the outer solar system where the satellites of the gas giant planets, Jupiter and Saturn, have been revealed to us by numerous spacecrafts (Voyager, Galileo, Juno or Cassini-Huygens) as icy but active worlds, composed of atmospheres charged with organic chemistry, cryovolcanoes, and permeable surfaces, often covered with ridges, fractures and large canyons. In addition, beneath more or less thick ice layers, these moons harbor large liquid water oceans. Indeed, icy moons like Europa and Ganymede around Jupiter or Titan and Enceladus around Saturn are possible habitable worlds, i.e. environments where life could have appeared in the past or could emerge in the future and which can teach us important facts about our own planet and how to protect it. In view of these conditions, the satellites of the giant planets will be explored in the future, and in particular in the vicinity of Jupiter, from 2030 onwards by the European JUICE and NASA's Europa Clipper missions, as well as later on, Titan, with NASA’s Dragonfly quadricopter. These missions will study their liquid subglacial water oceans, their capacity to contain nutrients and their energy sources, opening the path for such investigations in other exoplanetary systems. The search for habitable environments is rendered safe and sustainable through compliance with the requirements of the COSPAR Planetary Protection Policy.