NASA’s Mars rover Perseverance has uncovered rocks in a dry river channel that may hold potential signs of ancient microscopic life, scientists reported Wednesday.

They stressed that in-depth analysis is needed of the sample gathered there by Perseverance — ideally in labs on Earth — before reaching any conclusions.

Roaming Mars since 2021, the rover cannot directly detect life. Instead, it carries a drill to penetrate rocks and tubes to hold the samples gathered from places judged most suitable for hosting life billions of years ago. The samples are awaiting retrieval to Earth — an ambitious plan that’s on hold as NASA seeks cheaper, quicker options.

"One of the things we wanted to ask ourselves was, is it is it possible that organic matter might have played some role in the generation of these textural features?" said lead researcher Joel Hurowitz of Stony Brook University.

Hurowitz said it’s the best, most compelling candidate yet in the rover’s search for potential signs of long-ago life. It was the 25th sample gathered; the tally is now up to 30, with six more to go.

Collected last summer, the sample is from reddish, clay-rich mudstones in Neretva Vallis, a river channel that once carried water into Jezero Crater. This outcrop of sedimentary rock, known as the Bright Angel formation, was surveyed by Perseverance’s science instruments before the drill came out.

"It's a signature. It's a sort of left over sign. It's not life itself," said Nicky Fox, Associate Administrator, NASA Science Mission Directorate.

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