NASA’s Perseverance rover, operating on Mars since 2021, has discovered rocks in Jezero Crater that may hold potential traces of ancient microbial life. Findings are based on analysis of “Sapphire Canyon” rock samples in the clay-rich mudstones of Neretva Vallis, a former river channel that once fed Jezero Crater’s ancient lake.
Scientists stress that definitive conclusions require Earth-based laboratory analysis of samples, which is currently delayed due to stalled Mars Sample Return missions.
Key Highlights
Rover’s Role:
- Cannot directly detect life; instead, it drills rocks, collects samples in tubes, and identifies potential biosignatures.
- Over 30 samples collected, awaiting retrieval to Earth.
New Discovery (Summer 2024):
- Rocks contain two minerals linked to microbial activity on Earth:
- Vivianite (iron phosphate) – commonly found in sediments and peat bogs with decaying organic matter.
- Greigite (iron sulfide) – often produced by microbes as a metabolic byproduct.
- These minerals formed from chemical reactions between mud and organic matter at the ancient lake bottom.
Potential Biosignature:
- Detected in multi-billion-year-old sedimentary rocks.
- Similar reactions on Earth are often driven by microbes.
- Could indicate microbial activity in Mars’s past watery environments.
Scientific Perspectives
- Joel Hurowitz (Stony Brook University, lead author in Nature): Detected a “potential biosignature” in Martian mudstones.
- Independent experts (SETI Institute & Univ. of Massachusetts Amherst): Caution that non-biological processes could also explain the findings.
- Analogy: Findings are like “leftover fossils or byproducts of microbial meals.”
Challenges & Future Prospects
Sample Return Program:
- Originally planned for early 2030s, now delayed to 2040s.
- Costs escalated to $11 billion.
- NASA is seeking cheaper, faster alternatives; possible risk of cancellation.
Until samples are brought to Earth:
- Scientists must rely on stand-in materials and simulations.
- On-site Martian instruments provide limited certainty.
Significance
- Strengthens evidence that Mars once had habitable conditions in ancient lakes and rivers.
- Discovery of vivianite and greigite offers geological and geochemical clues to microbial activity.
- Highlights importance of sample return missions for conclusive evidence.
- Keeps alive the central question: Did Mars host microbial life billions of years ago?
Key Facts
- Perseverance Rover: Landed in Jezero Crater on 18 February 2021; part of NASA’s Mars 2020 Mission.
- Jezero Crater: A 45-km wide basin in Mars’s northern hemisphere; once contained an ancient lake and river delta.
- Mars Sample Return Mission: Joint NASA–ESA initiative, designed to retrieve Perseverance’s samples; currently delayed.
- Previous Mars Missions: Viking Landers (1970s), Curiosity Rover (2012–present), Insight Lander (2018–2022).