NASA’s Perseverance rover has collected a rock sample from a long-dried riverbed in Jezero Crater, which scientists are studying for its potential to reveal insights about Mars’ ancient environment. The rock formation, found in an ancient river valley called Neretva Vallis within Jezero Crater, is composed of clay and silt—materials known on Earth for preserving signs of past microbial life.

“After a year of scientific scrutiny, a rock sample collected by the Perseverance rover has been confirmed to contain a potential biosignature. The sample is the best candidate so far to provide evidence of ancient microbial life on Mars,” announced NASA via X social media.

The discovery was made while navigating the “Bright Angel” formation, a series of rocky outcrops along the edges of Neretva Vallis, an ancient river valley about 400 meters wide that once channeled water into Jezero Crater. This crater, located in Mars’ northern hemisphere, is believed to have hosted a lake between 3.2 and 3.8 billion years ago, making it a prime site for studying past habitability.

Perseverance’s onboard instruments, including the Scanning Habitable Environments with Raman and Luminescence for Organics and Chemicals (SHERLOC) and the Planetary Instrument for X-ray Lithochemistry (PIXL), analyzed the rock, revealing sedimentary layers rich in clay and silt. These minerals are significant because, on Earth, they are effective at trapping and preserving microbial fossils. The analysis also detected elements such as iron, sulfur, and phosphorus, which could have supported microbial life in Mars’ distant past, though non-biological processes could also explain their presence.

The sample is one of several rock cores Perseverance has collected since landing in Jezero Crater in February 2021. Scientists hope to return these samples to Earth through NASA’s planned Mars Sample Return mission for detailed laboratory analysis to further investigate their composition and origin.

For now, the rover continues exploring Jezero Crater, building on prior findings of water-altered rocks that suggest the crater was intermittently habitable billions of years ago. This work is part of NASA’s broader Mars Exploration Program, which aims to understand Mars’ geological and environmental history and assess its potential for past life.

The Perseverance team discovered the rock formation in an ancient, now-dry riverbed in Jezero Crater, and instruments revealed that it's composed of clay and silt. On Earth, these are excellent preservers of past microbial life. pic.twitter.com/0kCYqIjVdD

— NASA Mars (@NASAMars) September 10, 2025

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