NASA's Perseverance Mars Rover Studies Trove of Rocks on Crater Rim

NASA's Perseverance Mars Rover Studies Trove of Rocks on Crater Rim
by NASA Staff Writers
Pasadena CA (JPL) Apr 14, 2025

Scientists with NASA's Perseverance rover are exploring what they consider a veritable Martian cornucopia full of intriguing rocky outcrops on the rim of Jezero Crater. Studying rocks, boulders, and outcrops helps scientists understand the planet's history, evolution, and potential for past or present habitability. Since January, the rover has cored five rocks on the rim, sealing samples from three of them in sample tubes. It's also performed up-close analysis of seven rocks and analyzed another 83 from afar by zapping them with a laser. This is the mission's fastest science-collection tempo since the rover landed on the Red Planet more than four years ago.

Perseverance climbed the western wall of Jezero Crater for 3 0.5 months, reaching the rim on Dec. 12, 2024, and is currently exploring a roughly 445-foot-tall (135-meter-tall) slope the science team calls "Witch Hazel Hill." The diversity of rocks they have found there has gone beyond their expectations.

"During previous science campaigns in Jezero, it could take several months to find a rock that was significantly different from the last rock we sampled and scientifically unique enough for sampling," said Perseverance's project scientist, Katie Stack Morgan of NASA's Jet Propulsion Laboratory in Southern California. "But up here on the crater rim, there are new and intriguing rocks everywhere the rover turns. It has been all we had hoped for and more." That's because Jezero Crater's western rim contains tons of fragmented once-molten rocks that were knocked out of their subterranean home billions of years ago by one or more meteor impacts, including possibly the one that produced Jezero Crater. Perseverance is finding these formerly underground boulders juxtaposed with well-preserved layered rocks that were "born" billions of years ago on what would become the crater's rim. And just a short drive away is a boulder showing signs that it was modified by water nestled beside one that saw little water in its past.

Oldest Sample Yet? Perseverance collected its first crater-rim rock sample, named "Silver Mountain," on Jan. 28. (NASA scientists informally nickname Martian features, including rocks and, separately, rock samples, to help keep track of them.) The rock it came from, called "Shallow Bay," most likely formed at least 3.9 billion years ago during Mars' earliest geologic period, the Noachian, and it may have been broken up and recrystallized during an ancient meteor impact.

About 360 feet (110 meters) away from that sampling site is an outcrop that caught the science team's eye because it contains igneous minerals crystallized from magma deep in the Martian crust. (Igneous rocks can form deep underground from magma or from volcanic activity at the surface, and they are excellent record-keepers - particularly because mineral crystals within them preserve details about the precise moment they formed.) But after two coring attempts (on Feb. 4 and Feb. 8) fizzled due to the rock being so crumbly, the rover drove about 520 feet (160 meters) northwest to another scientifically intriguing rock, dubbed "Tablelands."

Data from the rover's instruments indicates that Tablelands is made almost entirely of serpentine minerals, which form when large amounts of water react with iron- and magnesium-bearing minerals in igneous rock. During this process, called serpentinization, the rock's original structure and mineralogy change, often causing it to expand and fracture. Byproducts of the process sometimes include hydrogen gas, which can lead to the generation of methane in the presence of carbon dioxide. On Earth, such rocks can support microbial communities.

Coring Tablelands went smoothly. But sealing it became an engineering challenge.

Flick Maneuver "This happened once before, when there was enough powdered rock at the top of the tube that it interfered with getting a perfect seal," said Kyle Kaplan, a robotics engineer at JPL. "For Tablelands, we pulled out all the stops. Over 13 sols," or Martian days, "we used a tool to brush out the top of the tube 33 times and made eight sealing attempts. We even flicked it a second time."

During a flick maneuver, the sample handling arm - a little robotic arm in the rover's belly - presses the tube against a wall inside the rover, then pulls the tube away, causing it to vibrate. On March 2, the combination of flicks and brushings cleaned the tube's top opening enough for Perseverance to seal and store the serpentine-laden rock sample.

Eight days later, the rover had no issues sealing its third rim sample, from a rock called "Main River." The alternating bright and dark bands on the rock were like nothing the science team had seen before.

Up Next Following the collection of the Main River sample, the rover has continued exploring Witch Hazel Hill, analyzing three more rocky outcrops ("Sally's Cove," "Dennis Pond," and "Mount Pearl"). And the team isn't done yet.

"The last four months have been a whirlwind for the science team, and we still feel that Witch Hazel Hill has more to tell us," said Stack. "We'll use all the rover data gathered recently to decide if and where to collect the next sample from the crater rim. Crater rims - you gotta love 'em."