The first images from NASA’s Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft show a planet in the process of losing parts of itself. Streams of hydrogen atoms drift away from the red planet, into the depths of space. The pictures are the first clear look at how crucial elements erode away from the Martian atmosphere, says Bruce Jakosky, a planetary scientist at the University of Colorado Boulder and the mission’s principal investigator. MAVEN’s goal is to measure how the solar wind and other factors nibble away at Mars’s atmosphere, so that scientists can better extrapolate how the once-thick atmosphere has thinned over billions of years. That process transformed Mars from a relatively warm, wet planet into a mostly dry, mostly frozen wasteland.