Perseverance Rover studies geologically rich Martian terrain

NASA’s Perseverance rover puts its robotic arm to work around a rocky outcrop called “Skinner Ridge” in Mars’ Jezero Crater. Composed of multiple images, this mosaic shows layered sedimentary rock facing a cliff in the delta, as well as one of the places where the rover abraded a circular plate to analyze the composition of a rock. Credits: NASA/JPL-Caltech/ASU/MSSS


NASA’s Perseverance rover is well into its second science campaign, collecting rock core samples from features in an area long considered by scientists to be a prime prospect for finding signs of ancient microbial life on Mars. The rover has collected four samples from an ancient river delta in the Red Planet’s Jezero Crater since July 7, bringing the total number of scientifically convincing rock samples to 12.

“We chose the Jezero Crater for Perseverance to explore because we thought it had the best chance of providing scientifically excellent samples – and now we know we sent the rover to the right place,” said Thomas Zurbuchen, Administrator NASA Associate for Science in Washington. “These first two scientific campaigns produced an incredible diversity of samples to be brought back to Earth by the Mars Sample Return campaign.”

Twenty-eight miles (45 kilometers) wide, Jezero Crater is home to a delta – an ancient fan-shaped feature that formed about 3.5 billion years ago at the convergence of a Martian river and of a lake. Perseverance is currently studying the sedimentary rocks of the delta, formed when particles of varying sizes were deposited in the once watery environment. During its first scientific campaign, the rover explored the floor of the crater, finding igneous rock, which forms deep underground from magma or during volcanic activity on the surface.

“The delta, with its various sedimentary rocks, contrasts beautifully with the igneous rocks – formed from the crystallization of magma – discovered at the bottom of the crater,” said Perseverance project scientist Ken Farley, from Caltech in Pasadena, California. . “This juxtaposition provides us with a rich understanding of the geologic history after the crater was formed and a diverse suite of samples. For example, we found sandstone that carries grains and rock fragments created far from Jezero crater – and a mudstone that includes intriguing organic compounds.

“Wildcat Ridge” is the name given to a rock about 3 feet (1 meter) wide that was probably formed billions of years ago when mud and fine sand were deposited in a lake evaporating salt water. On July 20, the rover abraded part of Wildcat Ridge’s surface so it could scan the area with the instrument called Scanning Habitable Environments with Raman & Luminescence for Organics & Chemicals, or SHERLOC.

SHERLOC analysis indicates that the samples exhibit a class of organic molecules that are spatially correlated with those of sulfate minerals. Sulfate minerals found in sedimentary rock layers can provide important information about the aqueous environments in which they formed.

What is organic matter?

Organic molecules are made up of a wide variety of compounds consisting primarily of carbon and typically include hydrogen and oxygen atoms. They can also contain other elements, such as nitrogen, phosphorus and sulfur. Although there are chemical processes that produce these molecules that do not require life, some of these compounds are the basic chemical building blocks of life. The presence of these specific molecules is considered a potential biosignature – a substance or structure that could be evidence of past life but could also have been produced without the presence of life.

In 2013, NASA’s Curiosity Mars rover found evidence of organic matter in rock powder samples, and Perseverance has previously detected organic matter in Jezero Crater. But unlike that previous discovery, this latest detection was made in an area where, in the distant past, sediments and salts were deposited in a lake under conditions in which life could potentially have existed. In its analysis of Wildcat Ridge, the SHERLOC instrument recorded the mission’s most abundant organic detections to date.

“In the distant past, the sand, mud and salts that now make up the Wildcat Ridge sample were deposited under conditions where life could have thrived,” Farley said. “The fact that organic matter was found in such sedimentary rock – known to preserve fossils of ancient life here on Earth – is significant. However, as good as our instruments aboard Perseverance are, further conclusions regarding the contents of the Wildcat Ridge sample will have to await its return to Earth for in-depth study as part of the agency’s Mars Sample Return campaign. .

The first stage of the NASA-ESA (European Space Agency) Mars Sample Return campaign began when Perseverance cored its first rock sample in September 2021. In addition to its rock core samples, the rover collected an atmospheric sample and two control tubes, all of which are stored in the rover’s belly.

The geological diversity of the samples already transported in the rover is so good that the rover team plans to deposit selected tubes near the base of the delta in about two months. After depositing the cache, the rover will continue its explorations of the delta.

“I have studied Martian habitability and geology for much of my career and know firsthand the incredible scientific value of returning a carefully collected set of Martian rocks to Earth,” said Laurie Leshin, director of NASA’s Jet Propulsion Laboratory in Southern California. “The fact that we are weeks away from deploying the fascinating Perseverance samples and only a few years away from arriving on Earth so that scientists can study them in exquisite detail is truly phenomenal. We will learn so much.

Learn more about the mission

A key focus of Perseverance’s mission to Mars is astrobiology, including caching samples that may contain signs of ancient microbial life. The rover will characterize the planet’s past geology and climate, pave the way for human exploration of the Red Planet, and be the first mission to collect and cache Martian rocks and regoliths.

Subsequent NASA missions, in cooperation with ESA, would send spacecraft to Mars to collect these sealed samples from the surface and return them to Earth for further analysis.

The Mars 2020 Perseverance mission is part of NASA’s Moon to Mars exploration approach, which includes Artemis missions to the Moon that will help prepare for human exploration of the Red Planet.

JPL, which is managed for NASA by Caltech, built and manages operations of the Perseverance rover.

To learn more about Perseverance:

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