Monthslong challenging trek

Perseverance rover will uncover mysterious Martian history after a monthslong challenging trek

By Ashley Strickland

After a steep monthslong trek, the Perseverance rover has reached the top of Jezero Crater on Mars. The site is a region unlike anything Perseverance has encountered during its 3 ½-year journey on the red planet.

Now, the robotic explorer is preparing to observe some of the oldest rocks on Mars, which could reveal the planet’s mysterious history, and potentially, whether its ancient environments were capable of supporting life. The rover is on a quest to determine if life ever existed on Mars by collecting samples that could contain ancient microfossils.

During its 3 ½-month climb, Perseverance ascended 1,640 vertical feet (500 vertical meters), acing tricky slopes angled at 20 degrees.

The ascent took place over some of the toughest terrain the rover has encountered since it landed on the crater floor in February 2021. But engineers at NASA’s Jet Propulsion Laboratory in Pasadena, California, who send commands that help the rover drive, came up with creative solutions, and the rover remains unscathed from the journey.

“They developed innovative approaches to overcome these challenges — even tried driving backward to see if it would help — and the rover has come through it all like a champ,” said Steven Lee, deputy project manager for Perseverance at JPL, in a statement.

“Perseverance is ‘go’ for everything the science team wants to throw at it during this next science campaign.”

Perseverance has already conducted four broad investigations of Jezero Crater’s floor, as well as the river delta that once fed into it, including exploring, observing, and sampling rocks and dust. The crater floor was once the site of an ancient lake 3.7 billion years ago.

Now that Percy has reached the top of the crater, it will begin its “Northern Rim” campaign, visiting multiple sites over the next year to take samples while traversing 4 miles (6.4 kilometers).

“The Northern Rim campaign brings us completely new scientific riches as Perseverance roves into fundamentally new geology,” said Ken Farley, project scientist for Perseverance at the California Institute of Technology, in a statement.

“It marks our transition from rocks that partially filled Jezero Crater when it was formed by a massive impact about 3.9 billion years ago to rocks from deep down inside Mars that were thrown upward to form the crater rim after impact,” Farley said. “These rocks represent pieces of early Martian crust and are among the oldest rocks found anywhere in the solar system. Investigating them could help us understand what Mars — and our own planet — may have looked like in the beginning.”

Turning back time

Perseverance’s first task is to head for Witch Hazel Hill, a large outcrop of rock about 1,500 feet (457 meters) down the other side of the rim. The rover will be moving up and down hills over the next six months in this region, the mission team shared Thursday at the American Geophysical Union’s annual meeting in Washington, DC.

“The campaign starts off with a bang because Witch Hazel Hill represents over 330 feet (101 meters) of layered outcrop, where each layer is like a page in the book of Martian history. As we drive down the hill, we will be going back in time, investigating the ancient environments of Mars recorded in the crater rim,” said Candice Bedford, a Perseverance scientist from Purdue University in West Lafayette, Indiana, in a statement. “Then, after a steep descent, we take our first turns of the wheel away from the crater rim toward ‘Lac de Charmes,’ about 2 miles (3.2 kilometers) south.”

The mission team is interested in Lac de Charmes because it lies in the plains beyond the rim, so the terrain is less likely to have been altered by the violent impact that formed Jezero Crater.

Then, Perseverance will undertake a 1-mile (1.6-kilometer) loop back to the rim to study an outcrop of large blocks that may be ancient broken bedrock. The team suspects the bedrock was broken by an impact that occurred when a celestial body slammed into Mars 3.9 billion years ago, creating a 745-mile-wide (1,200-kilometer) basin that scattered material from deep beneath the Martian crust.

Martian sightseeing

While the mission team is eagerly preparing for Perseverance’s next steps, it also took time to share highlights from the rover’s ascent.

During its climb, the rover captured images of intriguing rocks that suggest different facets of the red planet’s history.

At one point, Perseverance came across a zebra-striped rock that has scientists perplexed about its exact composition.

The rock, nicknamed Freya Castle, likely rolled downhill to arrive at its current home since it’s different from the bedrock it sits atop.

In October, the rover came across a field of brilliant white cantaloupe-size rocks, which the vehicle’s instruments confirmed as pure quartz, Farley said.

Perseverance had never spotted anything like these rocks.

“It’s potentially important, because quartz forms from the circulation of hot water through rocks in a setting like a hot spring,” Farley said. “This is a potentially habitable environment that’s totally different from the habitable environments that Perseverance investigated on the crater floor.”

While the quartz rocks are too small for Perseverance to drill into and collect a sample, the quartz field remains a place of interest as the rover investigates the crater rim further, especially because hot springs are known to be habitable environments on Earth, he said.

Now, Perseverance will study rocks that existed before the impact that created Jezero Crater, likely older than 4 billion years.

“The age of the solar system is about 4.5 billion years,” Farley said at the conference. “From my personal perspective, this is really one of the most exciting things that this mission is going to do, is to be looking at rocks that were formed so early in the history of the solar system, almost the dawn of the solar system.”

The solar system’s early days are poorly understood because Earth doesn’t have any rocks from this period due to its volcanic and other erosion-causing processes. But Mars can provide “a very good place” to try and understand how rocky planets formed in our solar system, Farley said.