The longest organic molecules identified to date on Mars have recently been detected by scientists from the CNRS1, together with their colleagues from France, the United States of America, Mexico and Spain. These long carbon chains, containing up to 12 consecutive carbon atoms, could exhibit features similar to the fatty acids produced on Earth by biological activity2. The lack of geological activity and the cold, arid climate on Mars have helped preserve this invaluable organic matter in a clay-rich sample for the past 3.7 billion years. It therefore dates from the period during which life first emerged on Earth. These findings are due to be published on March 24th 2025 in the journal PNAS.
The discovery was made using SAM3, co-funded by the French space agency CNES4. This is one of the instruments onboard NASA's Curiosity rover, which has been studying the Gale crater on Mars since 2012. This success paves the way for future interplanetary science missions in search of signs of complex, life-like chemistry. This will be one of the goals of ESA's upcoming ExoMars mission launched in 2028, and of the joint NASA-ESA Mars Sample Return mission in the 2030s. With an eye to exploration further out in the Solar System, the same international teams will build an instrument similar to SAM for Dragonfly, the drone that is due to explore the surface of Titan, Saturn's largest satellite, from 2034 onwards.
Notes
1 – From the « Atmosphères et observations spatiales » laboratory (CNRS/Sorbonne Université/Université de Versailles Saint-Quentin-en-Yvelines/Université Paris Saclay).
2 – They're present within animals fats, as well as vegetable fats and oils.
3 – Built by a French-American team of scientists, Sample Analysis at Mars is a small laboratory within Curiosity. its gas chromatograph and mass spectrometer allow it to identify molecules in collected samples.
4 - Centre national d'études spatiales – National Centre for Space Studies.
