NASA’s Curiosity rover has identified the most diverse array of organic molecules ever detected in a Martian rock sample. The sample, drilled in 2020 from a site nicknamed “Mary Anning 3” in honor of the English paleontologist, revealed 21 carbon-containing molecules, seven of which are new discoveries on the Red Planet. These findings were published on April 21, 2026, in Nature Communications.
The sample originates from Glen Torridon, a clay-rich region of Mount Sharp that formed billions of years ago in an environment with lakes and rivers. Clay minerals are known to be particularly effective at preserving organic compounds over long periods, even on the Martian surface, which has been exposed to radiation and oxidation for eons. This new analysis reinforces the idea that ancient Martian rocks can retain complex chemical traces for much longer than previously thought.
Among the notable molecules identified is a nitrogen-containing heterocycle, a ring structure of carbon atoms that also includes nitrogen. Molecules of this type are considered potential chemical precursors to more complex compounds linked to RNA and DNA. The sample also contained benzothiophene, a molecule with carbon and sulfur that has been found in some meteorites and is of interest for studies on prebiotic chemistry in the early solar system.
However, this discovery does not constitute definitive proof of past life. Organic molecules can form through biological processes, geological processes, or extraterrestrial contributions like meteorites. These new studies, enabled by Curiosity’s observations, suggest that Mars once possessed a chemistry compatible with habitable environments, and some of these molecular signatures may have survived within rocks until the present day.
The analysis was made possible by SAM (Sample Analysis at Mars), the miniaturized laboratory aboard Curiosity. For the Mary Anning 3 sample, scientists employed a “wet chemistry” procedure using tetramethylammonium hydroxide (TMAH), a reagent capable of breaking down larger molecules into more easily identifiable fragments. To validate the method, the team tested it on the Murchison meteorite, finding results consistent with some of those observed in the Martian sample, suggesting the possibility of even more complex organic compounds being present.
