Alberto Fairén is an interdisciplinary planetary scientist and astrobiologist, specializing in geochemistry, mineralogy, hydrogeology, sedimentology and environmental microbiology of extremophiles, with a particular focus on understanding the habitability of early Mars and the search for life on Mars and ocean worlds. He has previously worked at Cornell, NASA Ames and the SETI Institute; has explored different extreme environments (Arctic, Pilbara, Atacama, Rio Tinto, Pavillion, Mojave); and is a science team member in several Mars landed missions (NASA’s Opportunity, Curiosity, Perseverance) and forthcoming (ESA’s ExoMars). Alberto has been over one decade advocating for a methodic astrobiological exploration of Mars before sending manned missions, because it is foreseeable that terrestrial microorganisms will accompany human crews to Mars and find ways to adapt and survive: forward contamination will be certain and will affect potential biology on Mars in ways we are not equipped to understand yet.