After an arduous and prolonged journey, the Perseverance rover has successfully summited Jezero Crater on Mars, marking a significant milestone in its exploration of the Martian landscape. This region is unlike any other the rover has experienced throughout its 3.5-year expedition on the red planet. The robotic explorer is now poised to study some of the most ancient rocks on Mars, which could unveil the enigmatic history of the planet and possibly indicate whether its ancient environments were conducive to life. The rover's mission is to ascertain the existence of life on Mars by gathering samples that may harbor remnants of ancient microorganisms.

During its 3.5-month ascent, Perseverance climbed a vertical distance of 1,640 feet (500 meters), navigating steep inclines with angles reaching 20 degrees. The climb presented some of the most challenging terrain the rover has faced since its landing on the crater floor in February 2021. However, the engineering team at NASA’s Jet Propulsion Laboratory in Pasadena, California, who are responsible for sending commands to guide the rover's movement, devised innovative strategies to overcome these obstacles, ensuring the rover's safe passage. "They have crafted ingenious solutions to surmount these hurdles — even experimenting with driving in reverse to assess its efficacy — and the rover has emerged from these trials unscathed," remarked Steven Lee, the deputy project manager for Perseverance at JPL, in an official statement. "Perseverance is ready and capable of undertaking all the scientific endeavors the team intends to pursue in the forthcoming campaign."

Perseverance has already conducted a series of comprehensive investigations on the floor of Jezero Crater and the river delta that once flowed into it, encompassing exploration, observation, and sampling of rocks and dust. The crater floor was once home to an ancient lake that existed 3.7 billion years ago. Now, with Perseverance having reached the crater's summit, it is set to embark on its "Northern Rim" campaign, which will involve visiting multiple sites over the next year to collect samples while traversing a distance of 4 miles (6.4 kilometers). "The Northern Rim campaign ushers in an entirely new trove of scientific insights as Perseverance ventures into fundamentally novel geological terrain," stated Ken Farley, the project scientist for Perseverance at the California Institute of Technology, in an official statement. "This campaign signifies our transition from studying rocks that partially filled Jezero Crater at its formation due to a massive impact approximately 3.9 billion years ago to examining rocks from deep within Mars that were ejected upwards to form the crater rim post-impact," Farley elaborated. "These rocks are remnants of early Martian crust and are among the oldest rocks discovered within the solar system. Their investigation could provide insights into the early appearance of Mars and, by extension, our own planet."

Perseverance's initial task is to head towards Witch Hazel Hill, a sizable rock outcrop located approximately 1,500 feet (457 meters) beyond the rim's edge. Over the next six months, the rover will navigate the hilly terrain of this region, ascending and descending as it progresses. "The campaign kicks off with a flourish because Witch Hazel Hill presents over 330 feet (101 meters) of layered outcrop, with each layer akin to a chapter in the chronicles of Martian history. As we descend the hill, we will be journeying back in time, delving into the ancient environments of Mars recorded in the crater rim," explained Candice Bedford, a Perseverance scientist from Purdue University in West Lafayette, Indiana, in an official statement. "Subsequently, after a steep descent, we will steer our wheels away from the crater rim towards 'Lac de Charmes,' situated approximately 2 miles (3.2 kilometers) to the south."

The mission team is intrigued by Lac de Charmes due to its location in the plains beyond the rim, suggesting that the terrain is less likely to have been altered by the violent impact that formed Jezero Crater. Following this, Perseverance will undertake a 1-mile (1.6-kilometer) loop back to the rim to examine an outcrop of large blocks that may be remnants of ancient shattered bedrock. The team suspects that the bedrock was fractured by an impact event that occurred when a celestial object collided with Mars 3.9 billion years ago, creating a 745-mile-wide (1,200-kilometer) basin that dispersed material from deep within the Martian crust.

While the mission team is eagerly preparing for Perseverance's upcoming activities, they also took the opportunity to share highlights from the rover's ascent. Throughout its climb, the rover captured images of fascinating rocks that shed light on different aspects of the red planet's history. At one point, Perseverance encountered a zebra-striped rock that has left scientists puzzled regarding its exact composition. The rock, nicknamed Freya Castle, is believed to have rolled downhill to its current location, as it differs from the bedrock it rests upon.

In October, the rover discovered a field of bright white cantaloupe-sized rocks, which the vehicle's instruments confirmed to be pure quartz, according to Farley. Perseverance had never before encountered rocks of this nature. "This is potentially significant, as quartz forms from the circulation of hot water through rocks in an environment akin to a hot spring," Farley stated. "This represents a potentially habitable environment that is entirely distinct from the habitable environments that Perseverance investigated on the crater floor." Although the quartz rocks are too small for Perseverance to drill into and collect a sample, the quartz field remains an area of interest as the rover further investigates the crater rim, particularly because hot springs are known to be habitable environments on Earth.

Now, Perseverance will study rocks that predate the impact that created Jezero Crater, likely exceeding 4 billion years in age. "The age of the solar system is approximately 4.5 billion years," Farley remarked at the conference. "From my personal perspective, this is truly one of the most thrilling aspects of this mission, which is to examine rocks that were formed so early in the history of the solar system, nearly at its dawn." The early days of the solar system are not well understood, as Earth lacks rocks from this period due to volcanic and other erosive processes. However, Mars can offer "an excellent location" to attempt to comprehend how rocky planets formed within our solar system, Farley concluded.