Curiosity rover reaches ancient ridge of mud and boulders

NASA’s Curiosity rover has been exploring the lower slopes of Mount Sharp since 2014. Now, after three attempts, the rover has reached one of its primary destinations: Gediz Vallis Ridge. Back when liquid water could still exist on Mars’ surface, ancient rocky debris flows carried mud and rocks down the side of the mountain to form this ridge. Curiosity captured a 360-degree panorama of its new surroundings on August 19, 2023. NASA announced the arrival of Curiosity at the ridge on September 18.

Curiosity rover arrives at Gediz Vallis Ridge

Gediz Vallis Ridge is a long-sought destination for Curiosity. Wet debris flows from billions of years ago formed this region. So it preserves an important glimpse into what this part of Mars was like when there was water and mud. After three failed attempts to reach the ridge, Curiosity finally arrived on August 14, 2023. That was sol 3,923 for the rover. One sol is a Martian day. Previously, the rover had encountered obstacles such as sharp-edged “gator-back” rocks and slopes that were too steep to climb.

Ashwin Vasavada, Curiosity’s project scientist at NASA’s Jet Propulsion Laboratory, talked about the accomplishment:

After three years, we finally found a spot where Mars allowed Curiosity to safely access the steep ridge. It’s a thrill to be able to reach out and touch rocks that were transported from places high up on Mount Sharp that we’ll never be able to visit with Curiosity.

The ridge formed about three billion years ago. At the time, Mars still had liquid water on its surface. This was one of the last wet periods the planet experienced. Water in this area created mud, which flowed down the sides of the mountain, spreading out into a fan shape. The mud carried rocks and boulders of various sizes, some as large as cars. Later, wind sculpted the piled-up debris into the ridge we see today.

You can drag your cursor around within this 360-degree video to explore the view captured by Curiosity’s Mastcam while the rover was stopped next to Gediz Vallis Ridge. Video via NASA/ JPL-Caltech/ MSSS/ UC Berkeley/ YouTube.

NASA posted about the arrival at the ridge on X, showing the new image:

Nothing better than stopping for a pic (or 136) after a challenging hike ?

To create this immersive panorama, my team stitched together 136 images of this region called Gediz Vallis Ridge. It might have taken me 3 years and 4 attempts to get here, but the science is worth it. pic.twitter.com/FthK2VFnkJ

— Curiosity Rover (@MarsCuriosity) September 19, 2023

Curiosity rover sees a changing landscape

The higher up Mount Sharp, which is about three miles (five km) tall, that you go, the more the landscape changes. This reflects the changing conditions over time from when Gale crater – which the mountain is in the middle of – used to be a lake, to when it dried out. Curiosity has already found ample evidence for the ancient lake (or series of lakes) and streams in the distant past. The bottom of the crater was once the lakebed. As you ascend the mountain, things get progressively drier.

Where the rover is now, still on the lower slopes, there were mud flows running down the slopes of Mount Sharp. Gediz Vallis Ridge is one of the youngest geological features that Curiosity will see in its travels. It was also one of the last geological features to form on Mount Sharp. And now the rover can finally see it up close.

Ancient muddy debris

Gediz Vallis Ridge is interesting to scientists for a couple of primary reasons. It contains ancient remnants of mud flows which provide valuable clues about water in Gale crater at the time. Also, the debris flows transported many rocks and boulders. The rocks look dark in the rover images and appear rather out of place from the rest of the landscape. The reason is that they originated from much higher up on the mountain. This is exciting for the mission scientists, as they can now examine rocks from the upper parts of the mountain that Curiosity can’t get to.

Geologist William Dietrich at the University of California, Berkeley, described the scene at the ridge:

I can’t imagine what it would have been like to witness these events. Huge rocks were ripped out of the mountain high above, rushed downhill, and spread out into a fan below. The results of this campaign will push us to better explain such events not just on Mars, but even on Earth, where they are a natural hazard.

Altogether, Curiosity spent 11 days exploring Gediz Vallis Ridge. It took 136 images that were later combined into the panorama at the top of this post. You can also see the path that the rover took going up the mountain. The rover had previously passed through a region called Marker Band Valley. There, a thin layer of darker rock stands out from the rest of Mount Sharp. This is one of the locations where Curiosity found clues about the ancient watery history of Gale crater.

11 years of exploration

Curiosity safely landed in Gale crater on Mars at 10:31 p.m. Pacific Daylight Time on August 5, 2012. It has been busy ever since, seeing dust devils, seeing eclipses with the Martian moons, finding evidence for ancient lakes and megafloods, detecting nitrogen and even discovering little Martian hoodoos.

Lear more about the Curiosity mission

Bottom line: After three attempts, NASA’s Curiosity rover has finally reached a large ridge composed of ancient mud and rocks. The ridge preserves a record of Mars’ wet past.

Via NASA

Read more: Morning and afternoon on Mars, from Curiosity rover