by Nearly three years ago, NASA’s Perseverance rover landed on Mars as part of a decades-long effort to study whether the now-arid planet once supported life.
Jezero Crater It once housed a large lake and a river delta. car size Perseverance, equipped with sophisticated cameras and scientific instruments, has so far spent its days studying its surroundings and collecting a variety of intriguing 3.5 billion-year-old Martian rocks and soil scattered on the crater floor. As planned, the rover has dropped 10 tubes full of samples to the ground, where they await the arrival of another robot that will transport them back to Land closer scrutiny in the 2030s.
On Tuesday (December 12), NASA announced that the $2.7 billion robotic explorer accomplished all of its tasks and also made progress. 1,000 Martian days on the Red Planet. (A Martian day, or sol, lasts 24 hours and 37 minutes.) Initial analyzes of the rocks collected by the rover reveal that some of them contain many carbonate-rich minerals and tiny grains of silica, a combination that would likely have preserved any organic molecules. of the era and prevented them from decaying, similar to a “mummy tomb,” Morgan Cable of NASA’s Jet Propulsion Laboratory (JPL) in Southern California told reporters during a press conference Tuesday. .
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Some of the rocks also show strong evidence for the presence of an intriguing mineral called iron phosphate. Here on Earth, phosphate is found in the DNA of all known life forms and also dissolves easily in liquid water. “We know that phosphorus is incredibly important,” Cable said, “and we now have the strongest evidence ever collected that phosphorus was available in a form that life could access if it were there.”
“I would say mission accomplished,” said Ken Farley, a geochemist at the California Institute of Technology in Pasadena who serves as project scientist for the Perseverance mission. “We’ve acquired some very, very good samples.”
Speaking at the American Geophysical Union (AGU) conference being held this week in San Francisco and online, Farley said the 1,000-sol milestone also marks the beginning of an additional new mission beginning next spring that will take to Perseverance along the edge of Jezero. Crater, and possibly even beyond. Scientists suspect that ancient Martian groundwater in this region interacted with the rocks in a way that created a completely different environment than the one the rover has explored so far.
“It’s actually quite remarkable that there is a route we can take the rover,” Farley said, adding that Perseverance will roll 2.4 miles (4 kilometers) from its current location to reach the start of its exit path. . “That will allow us to access rocks that are much, much older.”
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While next year’s extra trip will aim to fill the 13 remaining sample tubes aboard the rover, the rocks collected so far are already helping scientists put together pieces of how Jezero Crater formed, which is He believes he was born from a asteroid Impacted about 3.9 billion years ago and then flooded by a long-lived river, it evolved into the parched, rock-strewn area that Perseverance shows us today.
The drastic transformation occurred in three main phases, explained Libby Ives, part of the Perseverance team at JPL, during Tuesday’s briefing. At some point about 3.7 billion years ago, a large, fast-moving river breached the crater rim and gushed in, carrying with it (and leaving behind) light-colored, fine-grained sand and mud seen by Perseverance in an area nicknamed the “bacon strip“Ives said.
Flood waters then apparently filled the crater until the lake was about 100 feet (30 meters) deep, which can be inferred from layers of gradually changing rock types sticking together, Ives said. . The third and final phase saw another colossal flash flood that threw round rocks 3.3 feet (1 m) wide across the crater.
“These are big rocks, they’re probably not something you can pick up yourself,” Ives said.
At some point in Mars’ history, water that flooded Jezero Crater (and flowed elsewhere on the planet) escaped into space and was “never seen again,” Farley said. “If it hadn’t been like that, all of this would have disappeared.”
The disappearance of surface water is believed to have been accelerated by the frequent solar storms of the then young sun, which stripped Mars’ once thick atmosphere. As its atmosphere became thinner and thinner, the planet lost more and more surface water, eventually becoming the frigid desert we know today. (Mars’ atmosphere is currently about 1% thicker than Earth’s at sea level.)
Among the countless boulders that clutter the Martian surface today, scientists are particularly interested in fine-grained rocks at a place called Hidden Harbor, whose fine white veins of sulfate are evidence of ancient aquatic activity.
“This is the type of rock that we would separate grain by grain and really study the individual grains very, very carefully,” said Meenakshi Wadhwa of Arizona State University, who serves as principal scientist for the Mars Sample Return (MSR) mission. . which aims to bring Perseverance samples to Earth.
“This would be one of the most audacious robotic missions ever undertaken,” Wadhwa said. “It remains incredibly important for its high strategic and scientific value.”
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Scientists do not yet have a precise timeline for when the surface of Mars was habitable and when it dried out, as that information can only be obtained by dating Martian rocks using equipment here on Earth. A robust analysis would also reveal whether the intriguing minerals Perseverance has detected are truly evidence of life as we know it and not just byproducts of physical processes.
At Tuesday’s briefing, Lori Glaze, director of NASA’s Planetary Sciences Division, emphasized the importance of returning samples collected by Perseverance to Earth. Studying that material in well-equipped laboratories around the world “is what will provide the ground truth for decades of remote sensing and in situ data we have from Mars exploration,” Glaze said.
NASA is leading the ambitious MSR mission, which aims to launch an orbiter and rocket lander in 2030, but remains under pressure due to cost overruns and unprepared architecture. In response to a report Of an independent review board that urged rethinking certain aspects of the design, Glaze said the mission team is currently evaluating different options to feasibly return those samples to Earth.
Under the current plan, Perseverance would load samples onto NASA’s lander, which would then launch the material into Mars orbit. Up there, a European orbiter would grab the sample capsule and haul it back to Earth. But next year’s additional trip will move the rover off the crater rim and away from its initial cache of samples on the crater floor, so team members have yet to determine exactly where the future recovery module should land. of samples. Glaze said one option may be to land the lander wherever Perseverance is at the time, or drive the rover back to the crater floor near the fallen samples.
When those samples finally reach Earth, they will be preserved “for decades and generations to come so that scientists not yet born can address questions we haven’t thought about yet, using instruments that haven’t been invented.” Glaze said.
