(CNN) – The Perseverance rover has begun a long climb up the steep rim of Jezero Crater on a quest to uncover some of the oldest rocks on Mars and the potential for environments that may have once supported life on the Red Planet.
The robotic explorer landed in Jezero Crater three and a half years ago. Since then, it has explored the site of an ancient lake and river delta and collected numerous rock samples. But its latest scientific journey could rewrite the way astronomers understand Mars.
“Perseverance has completed four science campaigns, collected 22 rock cores and traveled more than 18 miles (29 kilometers),” Art Thompson, Perseverance project manager at NASA’s Jet Propulsion Laboratory in Pasadena, California, said in a statement. “As we begin our journey on the crater rim, our rover is in excellent condition, and the team is eager to see what’s on the roof of this site.”
The rover will use its automatic navigation capabilities, which allow Perseverance to operate as an autonomous vehicle, to follow a route planned by the rover's engineers. The route will allow the rover to avoid hazards on the challenging climb. Perseverance will have climbed about 1,000 feet (300 meters) by the time it reaches the top of the crater in late 2024.
This ascent is something scientists have been waiting for for years, long before Perseverance landed on Mars.
About 4 billion years ago, some object crashed into Mars and created Jezero Crater, and the impact kicked up huge blocks of rock that became trapped on the rim of the crater.
“We should be able to access and sample some of the oldest rocks on Mars at the rim of the crater,” said Briony Horgan, co-investigator for the Perseverance rover mission and professor of planetary science at Purdue University in West Lafayette, Indiana.
“We think this includes everything from ancient sedimentary rocks that could preserve the earliest habitable environments on Mars, to the building blocks of the planet that formed the first crust at the dawn of the solar system.”
The crater rim will provide a window into the earliest period of Mars' history and could reveal evidence of hot springs that could have supported ancient microbial life, Horgan said.
The impact that created Jezero Crater also generated a lot of heat, partly from the energy of the object that slammed into Mars. Some of the heat also came from warmer rocks that existed beneath the Martian surface, as the planet was still cooling after forming 500 million years earlier. The impact stirred up those rocks from beneath the Martian surface.
If there was ground or surface water on Mars at the time, which scientists believe is likely, there would have been hydrothermal systems, said Ken Farley, Perseverance project scientist and professor of geochemistry at the California Institute of Technology.
With hydrothermal systems, hot water likely circulated through cracks in rocks and may have created the right environment for microbial life to thrive.
So far, Perseverance has investigated the site of the ancient lake bed and river delta, where life might have existed. The rim of Pico Turquino crater, as the hydrothermal rocks are called, offers another different possibility.
“In the scheme of overall mission objectives, finding evidence of possible life on Mars ranks very high up there, so we want to investigate as many potentially habitable environments as Mars has to offer,” Farley said.
The science team is also eager to reach Witch Hazel Hill, a large outcrop of black-and-white layered rocks that stretches for hundreds of meters. These rock layers may preserve information about the climate of Mars billions of years ago. The rover should get there within six to nine months.
The movement of tectonic plates and other erosive processes have erased some of the oldest rocks on Earth, but ancient rocks encoded with the history of Mars still exist on the red planet.
The solar system formed 4.55 billion years ago and the science team hopes to find and study Martian rocks that are 4.2 billion years old, Farley said.
During the long drive along the crater wall, Perseverance could encounter slopes with an angle of nearly 23 degrees. Normally, the team avoids any route that tilts the rover more than 30 degrees. But the rover is well prepared for the climb and is not in any danger, Farley said.
“Climbing up to the crater rim, while it would be a bit of an arduous journey for us humans, from a rover perspective, it’s actually not going to be a big deal,” said Steven Lee, Perseverance deputy project manager.
But the rover's pace can slow if it feels its wheels slipping on the Martian terrain or encounters large rocks during ascent.
Perseverance can observe the terrain as it drives, and if its wheels spin too much, the rover will stop and “call home for Mom, wait to be told what to do and we’ll figure it out on the ground,” Lee said.
The rover remains in excellent condition, with “no obstacles that in any way say we can’t continue to operate this vehicle for many more years,” Lee said.
By the time the rover climbs to the top of the rim, it will have traveled dozens of additional kilometers and captured tons of new images for the mission team to analyze.
“It’s a unique perspective for those of us who work day in and day out on the project,” Lee said. “You start to get a sense of Mars as a place very quickly. My memories of Perseverance’s journeys are very much like memories of hiking. I can actually think about what Mars is like from the landing site to where we are today.”
And the rover's perspective on the 45-kilometer-wide (28-mile) crater will provide some beautiful views.
“We’ll definitely get some amazing views,” Horgan said.
The biggest challenge will be for the science team as they determine which rocks to study closely and which to collect samples from. With so many intriguing school-bus-sized rock piles, the team will have to learn as much as they can while keeping the rover moving.
“We’ll have all these things in front of us,” Farley said, “so I think it’s going to be a very different kind of exploration.”
The team anticipates Perseverance will spend at least a few years beyond the crater rim collecting samples.
Meanwhile, questions remain about how those samples, along with those Perseverance collected inside the crater, will be returned to Earth as NASA reevaluates the Mars Sample Return program. The agency is evaluating different proposals and is expected to announce a decision in the fall.
The decision could determine how long and how far the rover will travel, as the vehicle may be responsible for delivering samples to a spacecraft for return to Earth.
“This part of the mission is essential to creating a sample collection that is the collection of everyone’s dreams,” Farley said. “For now, we’ll simply continue our investigation of the crater rim. And then, when the time comes, we’ll do whatever is necessary to support sample return to Mars.”
