Overview

• A Nature study details millimeter-scale nodules in the Bright Angel formation that pair organic carbon with iron‑phosphate (likely vivianite) and iron‑sulfide (likely greigite) minerals.
• Perseverance spotted the features, nicknamed “leopard spots” and “poppy seeds,” in 2024 at Neretva Vallis and cached a core from the Cheyava Falls rock.
• The team classifies the signals as potential biosignatures because similar mineral–organic associations on Earth often reflect microbially mediated chemistry.
• Scientists caution that abiotic processes could produce the same mineralogy, and rover instruments cannot perform the definitive isotopic and microscopic tests.
• NASA’s delayed Mars Sample Return effort has ballooned to about $11 billion with timelines slipping into the 2040s, and the agency is exploring cheaper, faster alternatives to bring the samples home.