MOUNT SHARP, MARS – JUNE 20: A self-portrait of NASA’s Curiosjune 20ity Mars rover shows the robot at a drilled sample site called “Duluth” on the lower slopes of Mount Sharp in Mars on July 25, 2018. A Martian dust storm reduced sunlight and visibility in Gale Crater. The north-northeast wall and rim of the crater lie beyond the rover, their visibility obscured by atmospheric dust.