WWU’s Melissa Rice helps uncover the potential of life on Mars

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WWU's Melissa Rice helps uncover the potential of life on Mars

September 12, 2025

by Mikayla King

WWU Communications

WWU Professor of Geology and Physics & Astronomy Melissa Rice, a member of NASA's Perseverance rover team, has helped uncover the potential that life once may have existed on Mars.

In July 2024, the Perseverance rover analyzed igneous and sedimentary rock samples from an outcrop of Mars' Jezero Crater that researchers coined as "Bright Angel." Organic molecules were detected in the Bright Angel mudstone through a tool that uses ultraviolet laser to determine the chemistry, crystal structure and physical properties of minerals. The rocks also had small spots containing the signature of two iron-rich minerals, vivianite and griegite, which are often produced by microbial life on Earth. However, these features can also be created by chemical reactions that don't involve life.

The NASA team determined that these discoveries indicated "potential biosignatures."

"Importantly these spots are not definitive evidence of life, but they indicate a potential for life, which is still a big deal for Mars," Rice said. "It will require bringing the rocks to Earth for laboratory study to determine if they are true biosignatures."

Rice and the NASA team published their findings in the prestigious scientific journal Nature in a paper titled, "Redox-driven mineral and organic associations in Jezero Crater, Mars."

"This publication means that the discovery has gone through a rigorous peer review process, and the possibility that life created these spots cannot be ruled out," Rice said.

In the past, Mars rover missions have been focused on looking for evidence of water on Mars in order to assess whether the Red Planet was ever habitable. Those missions were successful, and the Curiosity mission proved that the water on Mars would've been suitable to sustain life. Perseverance is taking the next step to see if Mars has ever been inhabited, Rice said.

"That is the big question we've been asking ever since scientists were staring at the Red Planet with telescopes: Is there life there, or was there ever life there?" Rice said. "We haven't found evidence that Mars was inhabited, but finding a potential biosignature is a big step in that direction. This is the first time we've seen some kind of feature on Mars that was hard to explain by any other means than microbial life."

Rice has been a part of NASA's rover science teams since 2006 and joined the Perseverance team in 2014 when she began to collaborate on designing and building the rover's Mastcam-Z cameras prior to the rover's launch. Rice, alongside a group of undergraduate and graduate students in the WWU Mars Research Lab, helped to operate Perseverance's Mastcam-Z from Western's campus.

"The Mastcam-Z cameras are the 'scientific eyes' of the rover and very critical to doing the surveying and scouting that led us to these specific rocks in Bright Angel," Rice said. "Mastcam-Z was also crucial to looking around at the broader context of where this discovery was made so that we could understand what type of geological environment these rocks were formed in."

Mastcam-Z is also used to observe the iron oxidation rate of the rocks. The chemical makeup of the potential biosignatures are redox features, or reduced iron, that were potentially a result of microorganisms changing oxidized iron to reduced iron, Rice said. Understanding the extent of types of iron in the Bright Angel region in turn allows researchers to understand how much iron oxide had been available for potential microorganisms to take advantage of.

"What we found was that some of the rocks from the vicinity are some of the most oxidized rocks we have encountered on the mission to date," Rice said. "What that means is that these are literally the reddest things we have yet seen on Mars."

The next step to prove these are biosignatures is to bring the Mars rocks to Earth for further testing, but that process has been stalled by budget constraints. Funding for the Mars Sample Return program, which has the unique mission of landing a craft on Mars, grabbing a load of samples, and bringing them back to Earth for analysis, was cut from the president's 2026 budget but has since been added back into the U.S. House of Representatives' budget proposal.

If funding is approved, NASA will be one step closer to answering the question scientists have been asking for centuries; in the meantime, rock samples from Bright Angel will continue to be collected and analyzed by Perseverance as it continues on its mission.

Read the full paper in Nature, and read more about Rice's work on Mars in Window.

Mikayla King ('17) covers the College of Science and Engineering and Woodring College of Education for the Office of University Communications. Reach out to her with story ideas at [email protected]