This self-portrait of NASA's Curiosity Mars rover shows the vehicle at the "Mojave" site, where its drill collected the mission's second taste of Mount Sharp. NASA

NASA's Curiosity Rover Traces Ancient Environmental Changes on Mars

The latest research suggests with even more certainty that Mars was once habitable, while revealing striking mineralogical diversity on the Red Planet.

NASA's Curiosity Mars rover examined a mudstone outcrop area called "Pahrump Hills" on lower Mount Sharp, in 2014 and 2015. This view shows locations of some targets the rover studied there. The blue dots indicate where drilled samples of powdered rock were collected for analysis. NASA/JPL-Caltech/MSSS