Remarks on Life Feasibility on the Red Planet

The current strong interest in the exploration of Mars leads to the question of the actual possibility of the presence or possible past or future development of life on the planet. Several clues suggest that liquid water could be stably present under the surface of Mars, but on the condition that it is rich in perchlorate salts, abundant in the Martian soil, which would allow for water to remain liquid at the very low temperatures found on the planet. In this work, the main evidence on the permissiveness of Martian environments to microbial life is reviewed, with particular attention to the evaluation of the tolerance limit to the perchlorates of different microorganisms. Furthermore, a reasonable theoretical approach is offered to calculate the stability of globular proteins in aqueous solutions rich in perchlorates, trying to provide, given the current lack of valid experimental data, a rational means to try to understand the behaviour of proteins in environmental conditions very far from those of Earth.