NASA's Curiosity Mars rover climbing toward ridge top

After a journey of five years, NASA's Curiosity rover has begun the steep ascent of "Vera Rubin Ridge," an iron-oxide-bearing ridge, which has grabbed scientists' attention since before the car-sized rover's landing.

"We're on the climb now, driving up a route where we can access the layers we've studied from below," Abigail Fraeman, a Curiosity scientist at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California, said Wednesday in a statement.

A major appeal of the ridge, also called "Hematite Ridge," is an iron-oxide mineral, hematite, which can form under wet conditions and reveal information about ancient environments of the red planet.

Commemorating pioneering astronomer Vera Cooper Rubin (1928-2016), Curiosity's science team informally named the feature "Vera Rubin Ridge", which has been recognized as one of four unique terrains on lower Mount Sharp before Curiosity's landing five years ago and therefore a key mission destination.

The ascent to the top of the ridge from a transition in rock-layer appearance at the bottom of it will gain about 65 meters of elevation, about 20 stories. The climb requires a series of drives totaling about 570 meters.

Before starting this ascent in early September, Curiosity had gained a total of about 300 meters in elevation in drives totaling 17.32 kilometers from its landing site to the base of the ridge, according to the mission team.

Studies of Mount Sharp with the Compact Reconnaissance Imaging Spectrometer for Mars, on NASA's Mars Reconnaissance Orbiter, identified hematite in the ridge and also mapped water-related clay and sulfate minerals in layers just above it.

In orbital spectrometer observations, the iron-oxide mineral hematite shows up more strongly at the ridge top than elsewhere on lower Mount Sharp, including locations where Curiosity has already found hematite, according to JPL.

Curiosity's telephoto observations of the ridge from just beneath it show finer layering, with extensive bright veins of varying widths cutting through the layers.

Researchers seek to gain better understanding about why the ridge resists erosion, what concentrated its hematite, whether those factors are related, and what the rocks of the ridge can reveal about ancient Martian environmental conditions.

Curiosity landed near Mount Sharp in the Gale Crater in August 2012 and reached the base of the mountain in 2014. It has since traversed through a diversity of environments where both water and wind have left their imprint.

The rover began to drive toward uphill destinations on Mount Sharp since its second two-year mission extension commenced on Oct. 1, 2016.

According to NASA, during the first year after its landing near the base of Mount Sharp, the Curiosity mission accomplished a major goal by determining that billions of years ago, a Martian lake offered conditions that would have been favorable for microbial life.

Curiosity has since traversed through a diversity of environments where both water and wind have left their imprint.

Vera Rubin Ridge and layers above it that contain clay and sulfate minerals provide tempting opportunities to learn even more about the history and habitability of ancient Mars.