NASA‘s Curiosity rover has collected the largest organic compounds ever discovered on the Martian surface, according to scientists who analyzed pulverized rock samples that could hint at the possibility of ancient life.
Most notably, the samples indicate more advanced prebiotic chemistry than any previous Martian samples. Curiosity’s onboard mini-lab, Samples Analysis at Mars (SAM), discovered 10 to 13 carbon compounds, including decane, undecane, and dodecane, which could all possibly be components of fatty acids.
NASA Curiosity Rover recovers Cumberland Sample
The sample comes from a rock target named Cumberland, located in Yellowknife Bay within the 3.7-billion-year-old Gale Crater. Scientists became intrigued by the area’s resemblance to an ancient lakebed, prompting the rover to divert from its primary destination, Mount Sharp, also located within the crater.
The Curiosity rover drilled the Cumberland sample in 2013, extracting material from a 0.6-inch by 2.6-inch hole in the rock. Caroline Freissinet, lead author of the new study, co-led a 2015 project that identified some of the same organic molecules in the sample, which has since undergone several rounds of SAM analysis.
Organic Origins
It’s currently impossible to determine the exact source of the molecules, which could have several origins. If they are fragments of fatty acids—key components of cell membranes and metabolic processes—they would represent a crucial step in the chemistry of life. However, their presence doesn’t confirm life, as certain geological processes, such as interactions between water and minerals in hydrothermal vents, can also produce fatty acids.
Intriguingly, the molecules’ 10 to 13 carbon range fits within the expected profile for biologically relevant compounds. Non-biological processes tend to produce molecules with fewer than 12 carbon atoms. Due to the calibration limits of SAM, even longer-chain molecules may have gone undetected.
While not definitive evidence of life on Mars, the discovery suggests that life’s chemical building blocks may have progressed further on the Red Planet than previously believed. Importantly, the findings challenge long-held concerns that Mars’s harsh radiation and oxidative conditions would destroy biosignatures—organic molecules that can only be produced by life. The ability to detect these compounds with an onboard mini-lab has researchers eager to see what future sample return missions could reveal using Earth-based instruments.
“Our study proves that even today, by analyzing Mars samples, we could detect chemical signatures of past life if it ever existed on Mars,” said lead author Caroline Freissinet, a research scientist at the French National Centre for Scientific Research in the Laboratory for Atmospheres, Observations, and Space in Guyancourt, France.
Additional Cumberland Findings
Organic molecules weren’t the only discoveries in the sample. It also contained clay minerals formed in water and sulfur, which can help preserve organics. Additionally, researchers found nitrates—essential for life on Earth—and methane, a gas often associated with biological processes. And perhaps most affirming of all, scientists confirmed their hunch from over a decade ago: Yellowknife Bay was once a lake bed.
“There is evidence that liquid water existed in Gale Crater for millions of years and probably much longer, which means there was enough time for life-forming chemistry to happen in these crater-lake environments on Mars,” said co-author Daniel Glavin, a senior scientist for sample return at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.
Investigating the Sample
Freissinet’s team initially performed an experiment to search for amino acids, heating the sample twice to measure the mass of the molecules released. While the amino acid tests yielded negative results, the unexpected detection of decane, undecane, and dodecane sparked interest. The team hypothesized that these compounds were breakdown products of larger fatty acid molecules—specifically undecanoic acid, dodecanoic acid, and tridecanoic acid.
space object
To validate this, they conducted laboratory experiments on Earth. They mixed undecanoic acid with a Mars-analog clay and heated the mixture. As expected, decane was released from the fatty acid, mirroring earlier findings in which undecane broke off from dodecanoic acid and dodecane from tridecanoic acid.
“We are ready to take the next big step and bring Mars samples home to our labs to settle the debate about life on Mars,” said Glavin.
The paper “Long-chain Alkanes Preserved in a Martian Mudstone” appeared on March 24, 2025 in The Proceedings of the National Academy of Sciences.
Ryan Whalen covers science and technology for The Debrief. He holds an MA in History and a Master of Library and Information Science with a certificate in Data Science. He can be contacted atryan@thedebrief.org, and follow him on Twitter@mdntwvlf.