Upon its landing in Mars’s Jezero crater—an area that once held Jezero lake—in February 2021, the rover headed west. This direction pointed to ancient riverbeds, deltas, and locations where water once flowed abundantly. By July 2024, having traveled for nearly three and a half years, it reached a river valley spanning a quarter-mile, where a 3.2-foot-long rock, named by NASA scientists, yielded significant findings. According to a report published in Nature, a sample extracted by Perseverance from this rock could hold potential biosignatures indicating past microbial life.
Acting NASA administrator Sean Duffy stated in a, “This discovery by… represents our closest approach to finding life on Mars.” He added, “Identifying a potential biosignature on the Red Planet is a monumental discovery that will deepen our knowledge of Mars.”
The Perseverance rover did not unearth fossilized or currently existing microbes. Instead, it found a rock displaying various colors—red, green, purple, and blue—dotted with poppy-seed-like specks and marked by what Perseverance scientists described as muted yellow leopard spots. These observations were highly significant. The rover’s instruments verified that the red areas consist of iron-rich mud, the purple areas of iron and phosphorus, and the yellow and green areas of iron and sulfur. All these elements are known to provide sustenance for microbes.
Meanwhile, these poppy-seed-like dots and leopard spots bear a resemblance to features created by metabolizing microbes on Earth. When the rover’s instruments examined these features, they identified two iron-rich minerals: vivianite and greigite. On Earth, vivianite commonly occurs in peat bogs and near decomposing organic material, which also serves as a food source for microbes. Both of these minerals can originate from microbial activity. Perseverance transmitted images of the rock’s unique features back to Earth, as X-ray and laser sensors simultaneously analyzed the chemical composition of the markings.
Joel Hurowitz, lead author of the Nature paper and a member of the Perseverance science team, stated at a Sept. 10 press conference, “What is compelling about these discoveries is that this particular blend of mud and organic matter is consistent with what we observe in Earth’s sediments. These minerals are frequently byproducts of microbial metabolic processes that consume organic matter, forming these minerals through those reactions.”
Katie Stack Morgan, Perseverance’s project scientist, commented in a statement, “Astrobiological assertions, especially those concerning the potential detection of past extraterrestrial life, demand exceptional proof.” She added, “Presenting such a pivotal finding, like a potential Martian biosignature, in a peer-reviewed journal is an essential part of the scientific method, guaranteeing the thoroughness, authenticity, and importance of our findings.”
However, these results are far from conclusive. The term chosen to describe the discovery—“potential biosignature”—is a highly specific scientific designation. As NASA outlined in its, a potential biosignature refers to “a substance or structure that could have a biological origin but necessitates additional data or further investigation before any definitive conclusion about the existence or non-existence of life can be made.” In essence, a Nobel Prize is not yet warranted.
Hurowitz noted at the press conference, “There exist non-biological mechanisms for creating these features that we cannot entirely discount.” He continued, “Therefore, our next steps involve conducting further research in Earth-based laboratories, and eventually returning the sample retrieved from this rock to Earth to conclusively determine the process responsible for these remarkable textures.”
Retrieving these rock samples for study on Earth is a high priority for NASA’s exploration plans. Perseverance embarked carrying 43 small titanium tubes, which it has been filling with Martian soil and rock, systematically depositing them on the surface. The sample referenced by Hurowitz is one of these stored Martian fragments. For several decades, NASA has discussed a mission, with Perseverance serving as the initial phase of this collection effort. However, the subsequent stages have not been fully outlined. NASA’s concept involves deploying another compact rover to Mars, which would follow Perseverance, gather the samples it left behind, and transfer them to a return vehicle. This vehicle would then launch from Mars, transporting them to an (ERO)—developed by the European Space Agency —that would be awaiting the valuable payload. The ERO would subsequently transport the sample tubes back to Earth.
Even though Perseverance has consistently filled its tubes and deposited them on the surface, the remaining hardware for the intricate MSR relay mission has not yet been constructed. Furthermore, the current administration might be impeding these plans. In early May, that proposed a 24% reduction in NASA’s funding, leading to the scaling back or cancellation of numerous programs. The MSR program was among those affected by these cuts. While Congress still needs to approve the request, Duffy was questioned about the MSR’s prospects at Wednesday’s press conference.
He responded, “Our approach will be to review our budgets.” He continued, “We will assess our timelines. And, consider how we can optimize spending. Also, what technologies are available to retrieve samples more swiftly? This is currently under analysis. The question remains: what is the most effective method?”
This response does not constitute a strong endorsement for MSR, but it also isn’t a rejection. While Washington deliberates the space agency’s future, the Perseverance team proceeds with its mission, directing the rover to search for evidence of Mars’s ancient history. The planet might have once supported life, and it could potentially still do so far beneath its surface in subterranean aquifers. These recent discoveries offer further indication that we might not have always been the sole inhabitants of our solar system.
