Perseverance rover begins steep ascent to study oldest parts of Mars

Subscribe to CNN's Wonder Theory newsletter. Explore the universe with news about amazing discoveries, scientific advances, and more..

CNN
—

The Perseverance rover has begun a long climb up the steep rim of Jezero Crater on a mission to discover some of the oldest rocks on Mars — and the possibility of environments that might have hosted life on the Red Planet.

Since landing in Jezero Crater three and a half years ago, the robotic explorer has explored an ancient lake site, a river delta and collected scores of rock samples. But its latest scientific journey could rewrite the way astronomers understand Mars.

“Perseverance has completed four science campaigns, collected 22 rock samples, and traveled more than 18 miles (29 kilometers) of unpaved terrain,” Art Thompson, Perseverance project manager at NASA’s Jet Propulsion Laboratory in Pasadena, California, said in a statement. “As we begin the Crater Rim campaign, our rover is in excellent shape, and the team is excited to see what’s out there.”

The vehicle will use autopilot capabilities, which allow the vehicle to operate like a self-driving car, to follow a path planned by the vehicle’s engineers. The path will allow the vehicle to avoid hazards during the challenging climb. The vehicle will gain about 1,000 feet (300 meters) in elevation when it reaches the top of the ridge toward the end of 2024.

This ascent is something scientists have been waiting for for years, long before Perseverance landed on Mars.

About 4 billion years ago, a type of body appeared. The asteroid hit Mars and created the Jezero Crater, the impact kicked up huge chunks of rock that became trapped in the rim of the crater.

“We should be able to get to some of the oldest rocks on Mars in the crater rim and take samples from them,” said Briony Horgan, a co-investigator on the Perseverance rover and a professor of planetary science at Purdue University in West Lafayette, Indiana.

“We think these include everything from ancient sedimentary rocks that could preserve the oldest habitable environments on Mars, to the building blocks of the planet that formed the earliest crust at the dawn of the solar system.”

The crater's rim will provide a window into the earliest period of Mars' history — and could reveal evidence of hot springs that may have supported ancient microbial life, Horgan said.

The impact that created Jezero Crater also generated a great deal of heat, partly due to the energy of the body that struck Mars. Some of the heat also came from hotter rocks that were beneath the surface of Mars, as the planet was still cooling after its formation half a billion years ago. The impact moved those rocks from beneath the surface of Mars.

If groundwater or surface water existed on Mars at that time, which scientists think is likely, there would have been hydrothermal systems, said Ken Farley, Perseverance project scientist and professor of geochemistry. At the California Institute of Technology.

In hydrothermal systems, hot water likely flowed through cracks in the rocks, perhaps creating the right environment for microbial life to flourish.

So far, Perseverance has explored the location of ancient lake beds and river deltas where life could have existed. The location of the rim of Pico Turquino crater, as the hydrothermal rocks are called, offers another different possibility.

“In the overall mission objectives, searching for evidence of potential life on Mars is at the forefront of the objectives, so we want to investigate as many habitable environments as possible that Mars might offer us,” Farley said.

The science team is also looking to reach Witch Hazel, a large outcrop of black and white layered rocks that stretches hundreds of meters. These layers of rock may preserve information about the Martian climate billions of years ago. The rover is expected to arrive there in six to nine months.

Plate tectonics and other erosive processes have erased some of the oldest rocks on Earth, but ancient rocks encoded with Mars' history still exist on the Red Planet.

The solar system formed 4.55 billion years ago, Farley said, and the scientific team expects to find and study Martian rocks that are 4.2 billion years old.

During the long journey along the crater wall, the rover could encounter slopes of about 23 degrees. The team typically avoids any route that would tilt the rover more than 30 degrees. But the rover is well prepared for the climb and is in no danger, Farley said.

“Climbing the crater rim, while it might be a bit of a trek for us humans, from the rover’s perspective it’s not really that big of a deal,” said Stephen Lee, Perseverance’s deputy project manager.

But the rover's rate of progress may slow if it feels its wheels slipping on Martian terrain or encounters large rocks while climbing.

Perseverance can monitor the terrain as it drives, and if its wheels slip too much, the vehicle will stop and “call home for mommy, wait until it’s told what to do and we’ll figure it out on the ground,” he told me.

He told me the vehicle is still in excellent condition, “and there are no obstacles in any way that would make us say we can't continue to operate this vehicle for many more years.”

By the time the probe reaches the top of the ridge, it will have traveled dozens of more kilometers and captured large amounts of new images for the mission team to analyze.

“It’s a unique perspective for those of us who work on the project every day,” he told me. “You quickly start to get a sense of Mars as a place. My memories of Perseverance’s missions are very similar to my memories of hiking. I can actually think about what Mars looked like from the landing site to where we are today.”

The rover's perspective above the 28-mile-wide (45-kilometer-wide) crater will provide some beautiful views.

“We will definitely get some amazing views back to where we came from in Jezero and to the plains beyond,” Horgan said.

The biggest challenge the science team will face is deciding which rocks to study up close and which rocks to collect samples from. With so many interesting rock piles the size of a school bus, the team will have to learn as much as they can while keeping the rover moving.

“We're going to see all of these things right in front of our eyes, so I think it's going to be a whole different kind of exploration,” Farley said.

The team expects Perseverance to spend at least a few years outside the crater's rim collecting samples.

Meanwhile, the question of how those samples, along with those collected by the Perseverance rover inside the crater, will be returned to Earth remains as NASA reevaluates its Mars sample return program. The agency is evaluating various proposals and is expected to announce its decision in the fall.

The decision could determine how long and how far the rover will travel, as the rover may be responsible for delivering samples to a spacecraft for transport back to Earth.

“This part of the mission is essential to creating the sample collection that everyone dreams of,” Farley said. “For now, we will continue our investigations around the crater rim. When the time comes, we will do whatever it takes to support the return of samples to Mars.”