Perseverance reveals more detail on Martian organic chemistry

The Perseverance Mars rover has found evidence of a range of organic molecules that suggest a more complex chemical cycle on the planet than previously thought.

The discovery in the Red Planet’s Jezero Crater might be the result of historic chemical interactions between water and rocks, or come from interplanetary dust or meteors, scientists say. However, biological origins are not being ruled out.

In any case, improving scientific understanding of Martian organic matter could help reveal carbon sources, with implications for the search for any possible signs of life.

The team led by Sunanda Sharma, a post-doctoral researcher fellow at NASA’s Jet Propulsion Lab, collected data from the rover’s Scanning Habitable Environments with Raman and Luminescence for Organics and Chemicals (SHERLOC) instrument, which was designed to offer a more detailed mapping and analysis of organic molecules minerals on Mars than earlier hardware.

The discovery of organic molecules — typically containing hydro-carbon or carbon-carbon bonds — is not a first. The paper, published in the science journal Nature this week, said several types of organic molecules have been previously detected in Martian meteorites and at Gale crater, explored by the Curiosity rover after 2012.

However, the new findings contribute to a more detailed understanding of organic chemistry on the planet, the researchers said.

“Evaluating the diversity and detectability of organic matter elsewhere on Mars is important for understanding the extent and diversity of Martian surface processes and the potential availability of carbon sources,” the paper said.

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NASA chose the Jezero Crater for the Perseverance landing owing to the site's history as an ancient lake basin, which made the site a stronger candidate for life on Mars.

Sharma and colleagues took data from two formations on the Jezero Crater floor — called Máaz and Séítah — and showed organic molecules were evident in all 10 targets. The diverse mineral association and distribution may be unique to each formation and could help explain the different ways organic matter may have originated, whether through a reaction with water, or through synthesis with volcanic materials.

“Our findings suggest there may be a diversity of aromatic molecules [a form of organic compounds] prevalent on the Martian surface, and these materials persist despite exposure to surface conditions. These potential organic molecules are largely found within minerals linked to aqueous processes, indicating that these processes may have had a key role in organic synthesis, transport or preservation,” the study concludes.

While confirmation of the findings may require samples to be returned to Earth for further analysis — NASA has plans to do just that — the latest results show the key building blocks for life may have been present for between 2.3 and 2.6 billion years. Meanwhile, there may be “undetected chemical species that could be preserved within these two potentially habitable paleo-depositional settings in Jezero crater,” the study said. ®