NASA’s Perseverance rover explores geologically rich terrain on Mars – ScienceDaily

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

“We chose Jezero Crater for Perseverance to study 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, NASA’s associate administrator for science at Washington. “These first two science campaigns have yielded an incredible variety of samples to be brought back to Earth by the Mars Sample Return Campaign.”

Twenty-eight miles (45 kilometers) wide, Jezero Crater hosts a delta, an ancient fan-shaped structure that formed about 3.5 billion years ago when a Martian river and lake merged. Perseverance is currently studying the delta’s sedimentary rocks, formed when particles of various sizes settled in the once aquatic environment. During its first science campaign, the rover explored the crater floor, discovering igneous rock that forms deep underground from magma or during volcanic activity on the surface.

“The delta, with its diverse sedimentary rocks, contrasts beautifully with the igneous rocks — formed by crystallization of magma — found on the crater floor,” said Perseverance Project Scientist Ken Farley of Caltech in Pasadena, California. “This mapping provides us with a rich understanding of the geologic history since the formation of the crater and a diverse set of samples. For example, we found sandstone that carries grains and rock fragments created far from the Jezero crater – and mudstone that includes intriguing organic compounds.”

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

SHERLOC analysis shows that the samples contain a class of organic molecules that are spatially related to those of the sulfate minerals. Sulfate minerals found in sedimentary rock layers can provide significant information about the aquatic environment in which they formed.

What Is it organic matter?

Organic molecules consist of a wide variety of compounds made mostly of carbon and usually include hydrogen and oxygen atoms. They may also contain other elements, such as nitrogen, phosphorus and sulphur. Although there are chemical processes that produce these molecules that do not require life, some of these compounds are the chemical building blocks of life. The presence of these specific molecules is considered a potential biosignature—a substance or structure that may be evidence of past life but may also have been produced without the presence of life.

In 2013, NASA’s Curiosity rover found evidence of organic matter in rock dust samples, and Perseverance has detected organic matter in Jezero Crater before. But unlike that previous discovery, this latest discovery was made in an area where, in the distant past, sediments and salts were deposited in a lake under conditions where life could potentially exist. In its analysis of Wildcat Ridge, the SHERLOC instrument recorded the most abundant organic finds of the mission 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 potentially have flourished,” Farley said. “The fact that the organic matter was found in such a sedimentary rock – known for harboring fossils of ancient life here on Earth – is significant. However, as capable as our instruments aboard Perseverance are, further conclusions about what is contained in the Wildcat Ridge sample will have to wait until it is returned to Earth for in-depth study as part of the agency’s campaign to return samples from Mars.”

The first step in the NASA-ESA (European Space Agency) campaign to return samples from Mars began when Perseverance retrieved its first rock sample in September 2021. Along with its rock core samples, the rover collected one atmospheric sample and two witness tubes. all of which are stored in the rover’s belly.

The geological diversity of the samples already carried by the rover is so good that the rover team is considering depositing selected tubes near the base of the delta in about two months. After depositing the cache, the rover will continue its exploration of the delta.

“I have studied the habitability and geology of Mars for most of my career, and I 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. “That Perseverance’s fascinating specimens are weeks away from being deployed, and only years away from being brought back to Earth for scientists to study in extraordinary detail, is truly phenomenal. We will learn so much.”

More about the mission

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

Subsequent NASA missions, in collaboration with ESA, will send spacecraft to Mars to collect these sealed samples from the surface and return them to Earth for in-depth analysis.

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

JPL, which is operated for NASA by Caltech, built and operates the Perseverance rover.

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