NASA Perseverance rover detects macromolecular carbon in Jezero crater rocks

NASA's Perseverance rover has identified macromolecular carbon (MMC) in two mudstone samples from the Bright Angel outcrop within Jezero crater, an ancient lakebed on Mars. The detection, made using the rover's SHERLOC instrument, involved shining an ultraviolet laser on the rocks and recording hundreds of organic signals, which researchers describe as the most robust organic detection in the crater so far.

The rocks contain large networks of carbon atoms that on Earth are associated with fossilized biological material and meteorites, but MMC can also arise from non-biological processes such as hydrothermal reactions, cosmic dust, or meteorite deposition. Scientists note that the MMC may have been preserved near the surface either because it is resistant to degradation or because it is shielded by minerals like clays or iron-rich soil.

"Measurements of two mudstones show hundreds of organic detections, making this the most robust organic detection in Jezero crater thus far, and, to our knowledge, the only detection of macromolecular carbon on a natural rock surface on Mars," the study states. Co-lead researcher Ashley Murphy called the finding "one of the most exciting findings to date," while planetary scientist Paul Byrne emphasized that the formation mechanism remains unknown.

The discovery adds to earlier detections of organic molecules by NASA's Curiosity rover and supports the selection of these rocks for future sample-return missions, which would allow detailed laboratory analysis on Earth. However, the Perseverance payload cannot distinguish between biotic and abiotic origins, and the planned Mars Sample Return mission has faced delays.