University of Iowa geologist takes her skills to space in search for life on Mars

IOWA CITY — If scientists can prove evidence of life on Mars — now or at any point in the past — “that would be a first.”

“That would be a really cool discovery by itself,” University of Iowa planetary geologist Valerie Payre said. “That would mean we might not be alone in the solar system or even the universe.”

And NASA — thanks to its Perseverance Mars rover and researchers like Payre who are analyzing its discoveries — might be one step, or stone, closer to that galactic breakthrough.

“The rover found this really interesting rock last summer,” Payre told The Gazette.

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The rover rumbled up to that rock — nicknamed “Cheyava Falls” — in the Jezero crater, a 28-mile land feature thought to have once been flooded with water. Given its promise for the potential to have hosted life, NASA chose the crater as its landing spot for Perseverance in 2020.

The rover — outfitted with a range of instruments, including the SuperCam, on which Payre is a co-investigator — came upon the promising specimen in July 2024 while exploring a set of rocky outcrops known as the “Bright Angel.”

“So the first thing was taking a photo of that rock,” Payre said. “And scientists could see some features on the rock that were never seen and never observed before. And that was really of interest, because on Earth, when you see these type of features, it's usually related to microbes or microorganisms living on that rock.”

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Specifically, the arrowhead-shaped 3.2-foot Cheyava Falls appeared to have colorful spots — potentially left behind by microbial life, according to NASA. Using the rover’s instruments to capture higher resolution images, scientists noted a pattern of minerals arranged to look like leopard spots — carrying the signature of two iron-rich minerals.

Vivianite, for one, is often found on Earth in sediments, bogs and decaying organic matter; greigite, the other, can be produced on Earth by certain forms of microbial life.

“The combination of these minerals, which appear to have formed by electron-transfer reactions between the sediment and organic matter, is a potential fingerprint for microbial life, which would use these reactions to produce energy for growth,” according to a NASA report on the discovery.

But, according to Payre, the minerals also can be generated without the presence of life.

“We're not sure that they are actual byproducts of life, but it could be,” she said.

And that’s where Payre, the other scientists and the rover are continuing to dig — both metaphorically and literally.

“Right now, the rover is on the rim of the crater — meaning it's right at the border between the inside and the outside of the crater — and this region is really interesting because it's where there are some rocks that come from deeper in the interior of Mars, potentially from deep in the crust, or even maybe from the mantle,” she said. “And so this is a type of rock that we don't see every day. So I'm really excited to look at those, what they are, and if they can help us better understand Mars.”

Adding life to the Mars story could dramatically alter scientists’ understanding of the red planet — given what we know about how life has and continues to affect climate and geology on Earth.

“We would need to add the contribution of life in geological models and climate models,” she said. “It would have a lot of implications for geology, for climate, and other atmosphere conditions, too. That would change a lot of our visions of Mars.”

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Interstellar geology

Having joined the UI faculty three years ago as an assistant professor from Northern Arizona University, Payre last year moved into the new UI School of Earth, Environment, and Sustainability — with her focus as a geologist on the school’s Earth programming.

“I'm a geologist by training, and what I do on Mars is also geology,” said Payre, who was added as a co-investigator on the NASA rover’s SuperCam instrument earlier this year, in May. “I don't do a lot of physics or astronomy. It's really geology that I'm doing. I look at the composition of rocks. I try to understand what rocks are, how they form. So that's a geologist’s work. And that's why I'm in the School of Earth, Environment, and Sustainability.”

Years past the rover’s initial mission time frame, Payre said the team just weeks ago asked for another NASA extension on the project — given its condition and the discovery it’s enabled.

“Everything is still working, so we can still do great science,” she said.

And even as the team waits on NASA’s extension decision, Payre said she’s poring over SuperCam images being transmitted over the 220 million miles separating Earth and Mars.

“We're actively studying and investigating these rocks right now,” she said, looking ahead to the prospect of more discovery on the red horizon.

Vanessa Miller covers higher education for The Gazette.

Comments: (319) 339-3158; vanessa.miller@thegazette.com