Rover findings offer insight into the Red Planet’s ancient landscape

CU Boulder geologist Lisa Mayhew is among scientists working to recreate the story of an ancient landscape that wouldn’t look out of place in Utah – only that piece of land is on Mars millions of miles away. kilometers from Earth.

Mayhew is a member of NASA’s Mars 2020 mission science team, which is led by the Jet Propulsion Laboratory in Southern California. In August, she and her colleagues published some of the first results of the Perseverance rover’s exploration of the red planet.

The findings take an in-depth look at Jezero Crater. More than 3 billion years ago, a large asteroid struck Mars, forming this geological feature that stretches almost 30 miles in diameter and contains sand dunes and steep cliffs. Using a suite of scientific instruments aboard the Perseverance rover, which is roughly the size of an SUV, researchers have begun to explore the past of this landscape, showing how igneous rock forms the bottom of the crater and how water reshaped the rocks at a time when a vast lake probably filled this area.

“We have a lot of information in orbit that informs what we think the geology, mineralogy and chemistry of Mars might be like,” said Mayhew, a research associate in the Department of Geological Sciences at CU Boulder. “But taking a rover there is an incredibly valuable tool to make sure we actually understand what’s going on.”

The new results are a bang for this fearless machine. The one-tonne Perseverance landed on Mars on February 18, 2021. He and Mayhew have been busy ever since. In more than 570 Martian days, or “sols”, the rover explored nearly 8 miles of the planet’s surface. The new studies focus on the first year of Perseverance, which the rover spent studying geological formations and features along the crater floor, including two named Máaz and Séítah.

Mayhew, who had previously only studied rocks on Earth, sees the mission as a chance to stretch his skills as a geologist and, at least vicariously, set foot on another world.

“I realize sometimes how crazy it is to do what I do,” she said. “I am truly grateful to have had the opportunity to be part of this groundbreaking science.”

written in the rock

Jezero Crater may look dry and dusty today, but more than 3 billion years ago it would have been almost unrecognizable. Here, water flowing from a creek fed a lake that grew and shrunk in size over the eons.

Mayhew and his colleagues attempt to pinpoint the chronology of this wetter past.

The team’s first set of findings focus on two geological formations, in particular: Máaz, Navajo for “Mars”, a feature that appears to cover the larger Séítah, Navajo for “among the sand”. To study this terrain, the researchers relied on several instruments on board Perseverance, including SuperCam. This pivoting instrument sits atop the rover and uses laser light to quantify elements and identify minerals in various rocks.

Mayhew is co-author of two papers led by Ken Farley of the California Institute of Technology and Roger Wiens of the Los Alamos National Laboratory detailing Perseverance’s first year on Mars. The studies were published on August 25 in the journals Science and Scientists progress. Other research teams released other mission results at the same time.

The group’s results point to a surprising origin for these formations: a body of hot, molten rock may have existed at the bottom of the crater, settling and cooling in several stages, potentially forming both Séítah and Máaz. Alternatively, Máaz may also have formed when separate lava flows moved into the crater.

“One idea is that it was a single body of rock formed from magma cooling underground,” Mayhew said. “But another model is that Máaz may have been formed separately by actively flowing lava on the surface of Mars.”

The project tackles a question that has driven much of its decades-long career: how does life carve out an existence in some of the most unlikely places on our planet?

In 2007 and 2008, Mayhew participated in research cruises that collected rocks from the bottom of the Pacific and Atlantic oceans to learn more about microbial life in hydrothermal systems. In 2015, she participated in an International Ocean Drilling Program research cruise that drilled underground in a hydrothermal system to access reacting rocks. At these sites, rocks react with water and produce chemicals such as hydrogen gas, nutrients that support vibrant communities of microbes that can, in turn, support more complex life like crustaceans and other invertebrates.

“My research has always focused on how water changes rocks and how this process can support life,” Mayhew said.

Back to Earth

To find out if Jezero’s rocks may have supported life billions of years ago, Mayhew and his colleagues will need to take a closer look at these pieces of Mars, under a microscope in labs on Earth.

During its mission, she explained, Perseverance uses a drill to dig about 40 Martian geological samples, storing them in sealed tubes. NASA is working with the European Space Agency (ESA) on separate missions that will travel to Mars to retrieve 30 of these tubes and bring them back to Earth.

Mayhew is one of 15 scientists on the mission’s Return Sample Science team. She and her colleagues work with other team members and Perseverance operators to decide which rocks the rover should collect. To date, the team has filled 13 of its sample tubes, 12 with rocks and one with an atmosphere sample, with plans to collect more rock samples soon. The team also sealed two “control” tubes to collect dust and particles in the atmosphere, allowing the researchers to measure any contamination that might be present during the sampling process.

Mayhew said the transition from an Earth-based geologist to a scientist working on an alien world has been difficult but rewarding.

“It felt like a big learning curve. I don’t have the experience of a lot of the team members, especially those who have worked on rover missions since Opportunity and Spirit’s inception in early 2000s,” Mayhew said. . “I constantly try to keep my ears open and learn from them.”

In March 2022, Perseverance left the crater floor for what might be the mission’s most exciting terrain: the delta. Here, the team will collect rocks that were deposited on the crater floor when water flowed down Mars.

Perseverance and Mayhew show no signs of stopping: “It’s a hectic schedule, and we have to keep moving forward.”