Free Astronomy Magazine January-February 2021

5 ASTRO PUBLISHING I n February 2021, NASA’s Mars 2020 Perseverance rover and NASA’s Mars Helicopter Ingenuity (pictured graphically in the background) will be the agency’s two new explorers on Mars. [NASA/JPL-Caltech] ble of protecting them from the ad- verse conditions of the external en- vironment. Among all possible ma- trices, those based on sedimentary clays are the most interesting, both because they are certainly produced in aqueous environments, and be- cause they are able to preserve or- ganic compounds on a geological scale. Among the most intriguing mixtures of clay minerals are the smectites, characterized by high plas- ticity and suitable for hosting orga- nic molecules between the thin layers of their sedimentary structure. These properties are well known on our planet, where smectites are the major reservoirs of carbon in marine sediments. On Mars, some organic molecules have already been identi- fied in rocks originating from clay de- posits in Gale Crater, but it is unclear whether their conservation is attrib- utable to smectites. In order to inter- pret as correctly as possible what the