The discovery of traces of methane in the atmosphere of Mars in 2004 has renewed speculation about the presence of life on the red planet. Indeed, this gas should not remain long in the Martian atmosphere which implies that any source renews the content. Among the possible origins, the one that fascinates the most is obviously in the form of microorganisms that would be cousins ​​of terrestrial methanogens. These are archaea that can thrive in extreme environments like deserts, Greenland ice and even geysers and hydrothermal vents. To develop, they need only carbon dioxide and hydrogen as a source of energy because they are not photoautotrophic organisms (performing photosynthesis), but chemotropic. Anaerobic, they are therefore able to thrive in anoxic environments, without oxygen, and devoid of organic matter. Clearly, they are indeed extremophiles and researchers have of course wondered if they would not be able to survive on Mars.