Mars Perseverance rover samples a 'treasure trove' of rocks at Jezero Crater’s rim

The diversity of rocks along the rim of Jezero Crater is offering an extraordinary peek into the deep past of Mars.

NASA’s Perseverance rover has been exploring this rugged Martian terrain and recently hit its fastest science-gathering streak since first touching down on the Red Planet, more than four years ago.

In just a few months, the rover has drilled into five rocks, sealed samples from three, and analyzed dozens more – all in an effort to understand Mars’s geological evolution better, and the potential it may once have had to support life.

The research team from NASA’s Jet Propulsion Laboratory in Southern California has been guiding the rover as it scales the Crater’s western wall.

After a three-and-a-half month climb, Perseverance reached the rim of the Crater on December 12, 2024, and is now exploring a 445-foot (135-meter) slope known as Witch Hazel Hill.

What the rover found there surprised even seasoned scientists.

Jezero Crater’s rocky tapestry

“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.

“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.”

The rocks on the crater rim tell a story of violent impacts and ancient geological processes.

Many of them are once-molten boulders blasted out from deep below the Martian surface, possibly during the very impact that created Jezero Crater. Others are layered formations that solidified in place, billions of years ago.

In some areas, rocks that were changed by water sit right next to rocks that probably remained dry for their entire history – a mix that gives scientists a lot to work with.

Digging into Mars’s early history

Perseverance began its crater-rim sampling campaign on January 28 with a rock dubbed “Silver Mountain,” that was taken from an outcrop called “Shallow Bay.”

This rock likely formed at least 3.9 billion years ago, during Mars’s earliest geological period, known as the Noachian.

The rock may have been broken up and re-formed by an ancient meteor impact, preserving clues about a chaotic time in the planet’s past.

Not far from there – about 360 feet (110 meters) away – the rover encountered an outcrop containing igneous minerals that had crystallized from magma deep within the Martian crust. However, that rock crumbled during two separate coring attempts.

A rock named “Tablelands” at Jezero Crater

So the rover traveled about 520 feet (158 meters) northwest to a different target – a rock named “Tablelands.”

Tablelands turned out to be a rich find.

Data from the rover’s instruments showed that this rock is made almost entirely of serpentine minerals. These form when water interacts with iron- and magnesium-rich rocks in a chemical process called serpentinization.

This reaction often causes the rock to fracture and expand. It can also produce hydrogen gas and methane – both of which are important when considering the planet’s ability to sustain life.

On Earth, similar rocks support entire microbial communities.

A sealing challenge for Perseverance

Coring Tablelands went well for the Perseverance rover, but sealing the sample turned into a frustrating challenge. Powdered rock collected at the top of the sample tube interfered with the seal.

“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.”

The “flick” is a unique maneuver. It involves the rover’s internal sample-handling arm pushing the tube against an internal wall, then quickly pulling back to shake loose debris. After multiple flicks and brushings, the team finally sealed and stored the sample on March 2.

Eight days later, Perseverance collected and sealed another sample, from a rock called “Main River,” without any trouble.

The alternating bright and dark bands on that rock stood out as something completely new to the team.

What’s next on Jezero Crater’s rim?

Since collecting the Main River sample, Perseverance has moved on to investigate more outcrops at Witch Hazel Hill – including Sally’s Cove, Dennis Pond, and Mount Pearl. The science team believes there’s still much more to learn from this area.

“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.”

As the mission continues, the rocks of Jezero Crater’s rim may hold some clues about the oldest and most revealing chapters in Mars’s long and complex history.

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