NASA’s Curiosity rover has been trundling around for nearly three years now, shooting lasers and drilling holes in rocks. That would be pretty boring if not for the fact it’s taking place on another planet 140 million miles away that may have once supported extraterrestrial life. Curiosity has been studying various objects on the surface of Mars since its arrival, but NASA recently decided to make a U-turn to go back and look at a particularly interesting specimen dubbed “Elk.”

The reverse in course isn’t substantial in the grand scheme of things, just 46 meters (151 feet). However, Curiosity can only move a few meters at a time because of the great distance between Mars and Earth. It’s safer to move it in short bursts and wait to make sure everything went as planned.

Curiosity analyzed Elk with two instruments on its first pass, the laser-firing Chemistry & Camera (ChemCam) and Dynamic Albedo of Neutrons (DAN). When analyzed, the data from these instruments showed high levels of silica, which we find here on Earth in the form of quartz. Rocks with high levels of silica are ideal for preserving organic material, like the remains of possible ancient Martian life forms.

NASA considers the ChemCam one of Curiosity’s most important tools. NASA’s Roger Wiens calls it Curiosity’s “eyes and ears.” It works by firing a laser at nearby objects to burn away dust and surface layers so the rover can get a better look at unaltered sections of rock with a built-in spectrophotometer. NASA has used this instrument on almost 1000 samples so far, and it’s fired more than 260,000 times.

Curiosity spotted Elk after climbing a small hill to scan an outcropping called “Missoula” (as seen at the top). This feature is notable because it contains a division where pale mudstone meets darker sandstone. Associated with this geology is Elk, which is one of several high-silica targets likely to be found in the area. Upon its return, Curiosity also scanned a similar object called “Lamoose” with different instruments. Now the rover will take its time and collect plenty of data from this interesting zone.

Curiosity has already traveled farther on Mars than any other rover. It landed in Gale Crater in 2012 and has since covered more than 6 miles (10 kilometers) on its path up Mount Sharp. Its primary mission was about two years, but it’s already well past that. NASA plans to send a successor rover to Mars in the 2020s to continue Curiosity’s work.