NASA’s Curiosity rover reaches the edge of Mars where water left a buildup of debris

Gediz Vallis Ridge is believed to be a remnant of powerful ancient debris flows, a destination long sought by the rover’s science team.

Three billion years ago, in the middle of one of the last wet periods MarsPowerful debris flows carried mud and rocks down the side of a massive mountain. The debris spread out in a fan shape that was later eroded by winds into a towering ridge, preserving an interesting record of the Red Planet’s watery past.

Curiosity’s Journey to the Ridge

Now, after three attempts NASAThe Curiosity Mars rover reached the ridge, capturing the formation in a 360-degree panoramic mosaic. Previous invasions have been thwarted by “crocodile back” rocks with sharp edges and steep slopes. After one of the toughest climbs the mission has ever faced, Curiosity arrived on August 14 in an area where it could study the long-awaited ridge with its 7-foot (2-meter) robotic arm.

Drag your mouse inside this 360-degree video to explore the view captured by Mastcam on NASA’s Curiosity while the Mars rover was parked next to the Gediz Vallis Ridge. Credit: NASA/Jet Propulsion Laboratory– California Institute of Technology / MSSS / University of California, Berkeley

“After three years, we finally found a place where Mars allowed Curiosity to safely reach steep hills,” said Ashwin Vasavada, Curiosity project scientist at NASA’s Jet Propulsion Laboratory in Southern California. “It is exciting to be able to reach out and touch rocks that were transported from high places on Mount Sharp that we would never be able to visit with curiosity.”

Discoveries on Mount Sharp

The rover has been ascending the lower part of 3-mile-high Mount Sharp since 2014, discovering evidence of ancient lakes and streams along the way. The mountain’s different layers represent different eras of Mars’ history. As curiosity grows, scientists are learning more about how the landscape changes over time. Gediz Vallis Ridge was among the last features to form on the mountain, making it one of the smallest geological time capsules Curiosity will see.

Mount Sharp rises about 3.4 miles (5.5 km) above the floor of Gale Crater. This oblique view of Mount Sharp is derived from a combination of elevation and imaging data from three Mars orbiters. The view is looking south-east. Gale Crater is 96 miles (154 kilometers) in diameter. Image source: NASA/JPL-Caltech/ESA/DLR/FU Berlin/MSSS

Rare insights and future endeavours

The rover spent 11 days on the ridge, busy taking photos and studying the formation of dark rocks that clearly originated elsewhere on the mountain. Debris flows that helped form the Gediz Vallis Ridge carried these rocks — and smaller ones on the ridgeline, some the size of cars — down from layers high on Mount Sharp. These rocks provide a rare look at the materials in the upper mountain that the curious can examine.

NASA’s Curiosity Mars rover used its ChemCam instrument to view rocks on the Gediz Vallis Ridge from Nov. 15-17, 2022, the 3653-3655 Martian day, or sol, of the mission. These rocks are believed to have been washed away by debris flows in the ancient past, and may be some of the latest evidence of liquid water that Curiosity sees on Mount Sharp. Image credit: NASA/JPL-Caltech/LANL/CNES/CNRS/IRAP/IAS/LPG

The rover’s arrival into the ridge also provided scientists with their first close-up views of the eroded remains of a geological feature known as a debris flow fan, where flowing debris spreads down the slope in a fan shape. Debris flow fans are common on both Mars and Earth, but scientists are still learning how they form.

Geologist William Dietrich, a member of the mission team, said University of California, Berkeley, who helped lead Curiosity’s study of the ridge. “Huge boulders were uprooted from the high mountain above, rushed down the hill, and spread out in a fan below. The results of this campaign will push us to provide a better explanation for such events not only on Mars, but even on Earth, where they pose a natural hazard.”

The path taken by NASA’s Curiosity Mars rover as it drove across the bottom of Mount Sharp is shown as a pale line here. Different parts of the mountain are classified by colour; Curiosity is currently located near the upper end of the Gediz Vallis Ridge, which is shown in red. Image source: NASA/JPL-Caltech/ESA/University of Arizona/JHUAPL/MSSS/USGS Center for Astrogeological Sciences

On August 19, the rover’s Mastcam camera captured 136 images of a scene on the Gediz Vallis Ridge, which when stitched together into a mosaic, provide a 360-degree view of the surrounding area. This panoramic image shows the path taken by Curiosity up the mountainside, including through Marker Band Valley, where evidence of an ancient lake was discovered.

While scientists are still mining images and data from Gediz Vallis Ridge, Curiosity has already turned to its next challenge: finding a route to the channel above the ridge so scientists can learn more about how and where water flows down Mount Sharp.

More about the mission

Curiosity was built by the Jet Propulsion Laboratory (JPL), operated by the California Institute of Technology (Caltech) in Pasadena, California. JPL is leading the mission on behalf of NASA’s Science Mission Directorate in Washington.