Overlaid on an image from NASA’s Mars Odyssey probe, this map shows Perseverance’s path between January 21 and June 11. The white dots show where the rover stopped after completing a pass along the Neretva Vallis river channel. The pale blue line indicates the route of the rover inside the channel. Credit: NASA/JPL-Caltech/University of Arizona
Neretva Vallis, originally intended to be little more than a path without boulders to slow down the rovers, provided the science team with plenty of geological possibilities.
After detouring across a dune field to avoid rumbling boulders, NASA’s Perseverance Mars rover reached its latest area of ​​scientific interest on June 9. The change in route not only reduced the estimated travel time to the area – nicknamed “Bright Angel” – by several weeks, but also gave the scientific team the opportunity to find exciting geological features in the ancient river channel.
Perseverance is in the later stages of its fourth science campaign, looking for evidence of carbonate and olivine deposits in the “Margin Unit,” an area along the inner rim of Lake Crater. Located at the base of the north wall of the channel, Bright Angel is characterized by rocky light outcrops that may represent either old rock exposed to river erosion or sediments that filled the channel. The team hopes to find carbonate- and olivine-rich rocks different from those in the Margin Unit and gather more clues about the Lake’s history.
To get to Bright Angel, the rover drove to a ridge along the channel of the Neretva Vallis river, which billions of years ago carried large amounts of water that flowed into the Jezero crater. “We started paralleling the channel in late January and were making pretty good progress, but then the boulders got bigger and more numerous,” said Evan Graser, associate director of strategic planning for Perseverance’s routes at NASA’s Jet Propulsion Laboratory in Southern California. “What was an average of over a hundred meters per Martian day was reduced to just tens of meters. It was frustrating.”
This mosaic, assembled from 18 images taken by NASA’s Perseverance rover, shows the boulder field on “Mount Washburn” on May 27. Fascinated by the variety of textures and chemical composition in the light-toned boulder in the middle, the rover’s science team has nicknamed the rock “Atoko Point.” Acknowledgments: NASA/JPL-Caltech/ASU/MSSS
Channel browsing
In rough terrain, Evan and his team use the rover’s images to plan a drive about 30 meters at a time. To get further on any given Martian day or sol, planners rely on Perseverance’s automatic navigation, or AutoNav, to take over.
But as the rocks piled up, the AutoNav decided more than once that it didn’t like the road and stopped, dimming the prospects of a timely arrival at Bright Angel. However, the team was hopeful, knowing they could find success traversing a quarter-mile (400 meter) dune field in the river channel.
“As we went, we followed the river channel to the north, hoping to find a section where the dunes were small and far enough apart for the rover to pass between them — because dunes are known to eat up rovers on Mars,” Graser said. . “The Endurance also needed an entry ramp that we could safely drive down. When the imagery showed both, we made a beeline for it.”
The Perseverance science team was also eager to travel through the ancient river channel because they wanted to explore ancient processes on Mars.
NASA’s Perseverance rover was traveling along the ancient Neretva Vallis river channel when one of its navigation cameras caught this view of an area of ​​scientific interest called “Bright Angel” on June 6 – a bright area in the far right. Credit: NASA/JPL-Caltech
Rock star
With AutoNav helping guide the way on the channel floor, Perseverance covered the 656 feet (200 meters) to the first science stop in one solo. The destination: “Mount Washburn,” a hill covered in interesting boulders, some of a type never before seen on Mars.
“The variety of textures and compositions at Mount Washburn was an exciting discovery for the team because these rocks represent a bag of geologic gifts brought down from and potentially beyond the crater rim,” said Brad Garczynski of Western Washington University in Bellingham. co-leader of the current scientific campaign. “But among all the different stones, there was one that really caught our attention. They nicknamed it “Atoko Point”.
About 18 inches (45 centimeters) wide and 14 inches (35 centimeters) tall, the mottled, light-colored boulder stands out in a field of darker ones. Analysis by the Perseverance SuperCam and Mastcam-Z instruments shows that the rock is composed of the minerals pyroxene and feldspar. In terms of size, shape and arrangement of mineral grains and crystals – and potentially chemical composition – Atoko Point is in a league of its own.
Some Perseverance scientists speculate that the minerals that make up Atoko Point were produced in a subsurface body of magma that may now be exposed at the rim of the crater. Others on the team wonder if the boulder was formed far beyond the walls of the Lake and carried there by swift Martian waters eons ago. Either way, the team believes that while Atoko is the first of its kind they’ve seen, it won’t be the last.
After leaving Mount Washburn, the rover headed 433 feet (132 meters) north to explore the geology of “Tuff Cliff” before embarking on a four-solo, 1,985-foot (605-meter) journey to Bright Angel. Perseverance is currently analyzing the rock outcrop to assess whether a rock core sample should be taken.
Citation: NASA Perseverance Fords Ancient River to Reach Science Goal (2024, June 13), Retrieved June 13, 2024, from https://phys.org/news/2024-06-nasa-perseverance-fords-ancient-river.html
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