彩民宝典

Perseverance looks back over its tire tracks in March 2022. (Credit: NASA/JPL-Caltech)

彩民宝典 geologist Lisa Mayhew is among the scientists working to recreate the history of an ancient landscape that wouldn鈥檛 look out of place in Utah鈥攐nly this terrain sits on Mars millions of miles from Earth.

Mayhew is a member of the science team for NASA鈥檚 , which is led by the Jet Propulsion Laboratory in southern California. In August, she and her colleagues published some of the first sets of results from the Perseverance rover鈥檚 exploration of the Red Planet.

The findings take a deep look at Jezero Crater. More than 3 billion years ago, a large asteroid struck Mars, forming this geologic feature that stretches almost 30 miles across and contains rolling sand dunes and craggy cliffs. Using a suite of scientific instruments aboard the Perseverance rover, which is about the size of an SUV, the researchers have begun to explore that landscape鈥檚 past鈥攕howing how igneous rock forms the crater floor and how water reshaped the rocks during a time when a vast lake likely filled this region.听

鈥淲e have a lot of information from orbit informing what we think the geology, minerology and chemistry of Mars may be,鈥� said Mayhew, a research associate in the Department of Geological Sciences at 彩民宝典. 鈥淏ut taking a rover there is an incredibly valuable tool to make sure we actually understand what鈥檚 happening.鈥�

The new results are a coup for that intrepid machine. The more than 1-ton Perseverance landed on Mars on Feb. 18, 2021. It and Mayhew have been busy ever since. Over more than 570 Martian days, or 鈥渟ols,鈥� the rover has explored nearly 8 miles of the planet鈥檚 surface. The new studies focus on Perseverance鈥檚 first year, which the rover spent investigating geologic formations and features along the crater floor, including two named M谩az and S茅铆tah.

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

鈥淚 realize sometimes just how crazy it is that I do what I do,鈥� she said. 鈥淚鈥檓 really appreciative that I鈥檝e had the opportunity to be part of this groundbreaking science.鈥�

Written in rock

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

Mayhew and her colleagues are trying to flesh out the timeline of that wetter past.

The team鈥檚 first set of findings home in on two geologic formations, in particular: M谩az, Navajo for 鈥淢ars,鈥� a feature that appears to overlie the larger S茅铆tah, Navajo for 鈥渁mong the sand.鈥� To study this terrain, the researchers relied on several instruments aboard Perseverance, including SuperCam. This swiveling instrument听sits on top of the rover and uses laser light to quantify elements and identify minerals present in various rocks.

Mayhew is a co-author on two papers led by Ken Farley of the California Institute of Technology and Roger Wiens of Los Alamos National Laboratory detailing Perseverance鈥檚 first year on Mars. The studies were published on Aug. 25 in the and . Other research teams published more findings from the mission at the same time. 听

The group鈥檚 results point to a surprising origin for these formations: A body of hot, molten rock may have existed at the crater floor, settling and cooling in several stages, potentially forming both S茅铆tah and M谩az. Alternatively, M谩az may also have formed when separate lava flows moved into the crater.

鈥淥ne idea is that this was a single body of rock formed from magma cooling underground,鈥� Mayhew said. 鈥淏ut another model is that M谩az may have been formed separately by lava actively flowing on the surface of Mars.鈥�

The project touches on a question that has motivated much of her decades-long career: How does life carve out an existence in some of the most unlikely places on our planet?听

In 2007 and 2008, Mayhew sailed on 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 down into the subsurface of a hydrothermal system to access actively reacting rocks.听At these sites, rocks react with water and produce chemicals such as hydrogen gas鈥攏utrients that support vibrant communities of microbes that can, in turn, support more complex life such as crustaceans and other invertebrates.听

鈥淢y research has always addressed how water alters rocks and how that process can support life,鈥� Mayhew said.

Returning to Earth

To find out if rocks in Jezero may have supported life billions of years ago, Mayhew and her colleagues will need to take a much closer look at these chunks of Mars鈥攗nder the microscope in labs on Earth.

During its mission, she explained, Perseverance is using a drill to excavate roughly 40 Martian geologic samples, storing them in sealed tubes. NASA is working with the European Space Agency (ESA) on separate missions that will travel to Mars to pick up 30 of those tubes and bring them back to Earth.

Mayhew is one of 15 scientists on the mission鈥檚 Return Sample Science team. She and her colleagues work with other team members and Perseverance鈥檚 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 a sample of atmosphere, with plans to collect more rock samples soon. The team has also sealed two 鈥渨itness鈥� tubes to collect dust and particles in the atmosphere, allowing researchers to measure contamination that might be present during the sampling process.

Mayhew said that transitioning from an Earth-based geologist to a scientist working on an alien world has been tough but rewarding.

鈥淚t has felt like a big learning curve. I don鈥檛 have the background that a lot of people on the team have, especially those who have been working on rover missions since Opportunity and Spirit went up in the early 2000s,鈥� Mayhew said. 鈥淚鈥檓 constantly trying to keep my ears open and learn from them.鈥�

In March 2022, Perseverance left the crater floor for what may be the most exciting terrain of the mission鈥攖he delta. Here, the team will collect rocks that were deposited onto the crater floor when water once flowed on Mars.听

Perseverance, and Mayhew, are showing no signs of stopping: 鈥淚t鈥檚 a hectic schedule, and we have to keep moving.鈥�