Some of the recently collected samples include organic matter, indicating that Jezero Crater, which likely once contained a lake and the delta that emptied into it, had potentially habitable environments 3.5 billion years ago.
“The rocks we’ve been investigating in the delta have the highest concentration of organic matter we’ve found so far on the mission,” said Ken Farley, Perseverance project scientist at the California Institute of Technology in Pasadena.
The rover’s mission, which began on the Red Planet 18 months ago, includes searching for signs of ancient microbial life. perseverance is collecting rock samples that could to have preserved these flags biosignatures. Currently, the rover contains 12 rock samples
digging in the delta
The site of the delta makes Jezero Crater, which stretches 45 kilometers (28 miles), particularly high interest in NASA scientists. The fan-shaped geological feature, once present where a river converged with a lake, preserves layers of Martian history in sedimentary rock, which formed when particles coalesced in this previously water-filled environment.
The rover investigated the crater floor and found evidence of igneous or volcanic rock. During its second campaign to study the delta over the past five months, Perseverance has found rich layers of sedimentary rocks that add to the story of Mars’ ancient climate and environment.
“The delta, with its various sedimentary rocks, contrasts beautifully with the igneous rocks, formed from the crystallization of magma, discovered on the crater floor,” Farley said.
“This juxtaposition gives us a rich understanding of the geologic history after the crater formed and a diverse sample set. For example, we found a grain-carrying sandstone and rock fragments created far from Jezero Crater.”
The mission team dubbed one of the rocks Perseverance sampled Wildcat Ridge. The rock likely formed when mud and sand settled in a wasted saltwater lake billions of years ago. The rover scraped the surface of the rock and analyzed it with an instrument known as Scanning Habitable Environments with Raman & Luminescence for Organics & Chemicals, or SHERLOC.
This rock-destroying laser works like an elegant black light to discover chemicals, minerals and organic matter, said Sunanda Sharma, a SHERLOC scientist at NASA’s Jet Propulsion Laboratory in Pasadena.
The instrument’s analysis revealed that the organic minerals are likely aromatic, or stable molecules of carbon and hydrogen, which are connected to sulfates. Sulfate minerals, often found interbedded within sedimentary rock layers, retain information about the aqueous environments in which they formed.
Organic molecules are of interest on Mars because they represent the building blocks of life, such as carbon, hydrogen, and oxygen, as well as nitrogen, phosphorus, and sulfur. Not all organic molecules require life to form because some can be created through chemical processes.
“While the detection of this class of organic compounds alone doesn’t mean life was definitely there, this set of observations is starting to look like some things we’ve seen here on Earth,” Sharma said. “Simply put, if it’s a scavenger hunt for potential signs of life on another planet, organic matter is a clue. And we’re getting stronger and stronger clues as we go through our delta campaign.”
Both Perseverance and the Curiosity rover have found organic matter on Mars before. But this time, the detection occurred in an area where life may once have existed.
“In the distant past, the sand, mud, and salts that now make up the Wildcat Ridge sample were deposited in conditions in which life could have thrived,” Farley said.
“The fact that organic matter was found in such a sedimentary rock, known from preserved fossils of ancient life here on Earth, is important. However capable our instruments aboard Perseverance “There are more conclusions about what Wildcat contains. The Ridge sample will have to wait until it is returned to Earth for in-depth study as part of the agency’s Mars Sample Return campaign.”
Sample return to Earth
The samples collected so far represent such a wealth of diversity from key areas within the crater and delta that the Perseverance team is interested in depositing some of the collection tubes at a designated site on Mars within about two months, Farley said.
Once the rover drops off samples in this cache depot, it will continue to explore the delta.
Future missions may collect these samples and return them to Earth for analysis using some of the most sensitive and advanced instruments on the planet. Perseverance is unlikely to find indisputable evidence of life on Mars because the burden of proof to establish it on another planet is so high, Farley said.
“I have studied the habitability and geology of Mars for much of my career and know firsthand the incredible scientific value of returning a carefully collected set of Mars rocks to Earth,” said Laurie Leshin, director of the Mars Propulsion Laboratory. NASA jet, in a statement. .
“That we are weeks away from deploying the fascinating Perseverance samples and only a few years away from bringing them back to Earth so scientists can study them in exquisite detail is truly phenomenal. We will learn a lot.”
Some of the various rocks in the delta were about 20 meters (65.6 feet) apart, each telling a different story.
One piece of sandstone, called Skinner Ridge, is evidence of rocky material that was likely transported into the crater from hundreds of miles away, representing material the rover will not be able to travel to during its mission. Wildcat Ridge, on the other hand, preserves evidence of clays and sulfates coming together and forming rocks.
Once the samples are in laboratories on Earth, they could reveal information about potentially habitable Martian environments, such as chemistry, temperature, and when the material was deposited in the lake.
“I think it’s safe to say that these are two of the most important samples that we will collect on this mission,” said David Shuster, Perseverance return sample scientist at the University of California, Berkeley.
