NASA's Perseverance Rover looks back as it climbs the Slippery Slope

Heading up the side of Jezero Crater, the agency's newest Red Planet off-roader looks back to its landing site and explores the path ahead.

NASA's Mars rover Perseverance is traveling a steep route up the western wall of Jezero Crater, aiming to reach the rim in early December. During the ascent, the rover not only took a wide look at the interior of Jezero Crater, but also took pictures of the tracks it left along the way after some wheel slip.

Composed of 44 individual images taken on September 27th, the 1,282nd. Taken on Mars Day of the Perseverance mission, the image mosaic shows many of the landmarks and Martian firsts that made the rover's three-and-a-half-year exploration of Jezero so memorable, including the rover's landing site, the site where sedimentary rock was first found, the site of the first Sample depots on another planet and the final airfield for NASA's Ingenuity Mars Helicopter. The rover captured the view near a spot the team calls “Faraway Rock,” about halfway through its climb up the crater wall.

“The image not only shows our past and present, but also shows the greatest challenge in getting to where we want to be in the future,” said Rick Welch, Perseverance deputy project manager from NASA's Jet Propulsion Laboratory in Southern California. “If you look at the right side of the mosaic, you get an idea of ​​what we are dealing with. Mars didn’t want to make it easy for anyone to get to that ridge.”

On the right side of the mosaic you can see a slope of about 20 degrees. While Perseverance has climbed 20-degree inclines before (NASA's Curiosity and Opportunity rovers both had ridges at least 10 degrees steeper), this is the first time it has climbed such a steep incline on such a slippery surface has.

During much of the ascent, the rover passed over loosely packed dust and sand with a thin, brittle crust. On several days, Perseverance traveled only about 50% of the distance it would travel on less slippery surfaces, and on one occasion only 20% of the planned distance.

“Mars rovers have driven over steeper terrain, and they have driven over slipperier terrain, but this is the first time they've had to do both on this scale,” said JPL's Camden Miller, the rover planner was, or “driver,” for Curiosity and is now taking on the same role on the Perseverance mission. “For every two steps forward that Perseverance takes, we have taken at least one step back. The rover planners saw that this would be a long, hard job, so we came together to think of some options.”

On October 3, they sent Perseverance commands to test strategies to reduce slip. First, they had it back up the slope (tests on Earth have shown that the rover's “rocker-bogie” suspension system maintains better traction when reversing under certain conditions). Then they tried to drive across the slope (switchbacks) and get closer to the northern edge of the “Summerland Trail,” the name the mission gave to the rover's route up the crater rim.

Data from these efforts showed that while all three approaches improved traction, staying near the northern edge of the slope proved most beneficial. Rover planners believe the presence of larger rocks closer to the surface made the difference.

“That’s the plan right now, but we may need to change things down the road,” Miller said. “No Mars rover mission has ever attempted to climb such a large mountain so quickly. Because of the scientific opportunities up there, the science team wants to reach the top of the crater rim as quickly as possible. It’s up to us rover planners to find a way to get them there.”

In a few weeks, Perseverance is expected to scale the crater rim at a place the science team is calling “Lookout Hill.” From there it's about a quarter of a mile (450 meters) to “Witch Hazel Hill”. Orbital data shows that Witch Hazel Hill contains light-colored, layered bedrock. The team is excited to compare this new location to Bright Angel, the area where Perseverance recently discovered and sampled the Cheyava Falls rock.

The rover landed on Mars carrying 43 tubes for collecting samples from the Martian surface. To date, Perseverance has sealed and cached 24 rock and regolith (broken rock and dust) samples, as well as one atmosphere sample and three witness tubes. Early in mission development, NASA set a requirement that the rover be able to cache at least 31 samples of rock, regolith and witness tubes at Jezero over the course of the Perseverance mission. The project added 12 tubes, bringing the total to 43. The extras were included in anticipation of the difficult conditions on Mars, which could result in some tubes not functioning as intended.

NASA decided to retire two of the empty replacement tubes because accessing them would pose a risk to the rover's small internal sample-handling robotic arm needed for the task: A wiring harness connected to the arm could become caught in a fastener on the frame when grasped The two empty sample tubes get caught in the rover.

Because these spares have now been retired, Perseverance currently has 11 empty rock sample tubes and two empty witness tubes.

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

NASA's Mars Sample Return Program, in collaboration with ESA (European Space Agency), aims to send spacecraft to Mars to collect these sealed samples from the surface and bring them back to Earth for in-depth analysis.

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

NASA's Jet Propulsion Laboratory, managed by Caltech for the agency, built the Perseverance rover and manages operations.

More information about Perseverance:

https://science.nasa.gov/mission/mars-2020-perseverance

Karen Fox/Molly Wasser
NASA Headquarters, Washington
202-358-1600
[email protected] / [email protected]

DC Agle
Jet Propulsion Laboratory, Pasadena, California.
818-393-9011
[email protected]

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