The NASA orbiter that arrived at Mars in 2014 to study atmospheric loss was MAVEN.
MAVEN stands for Mars Atmosphere and Volatile Evolution. NASA launched it on November 18, 2013, and it entered orbit around Mars on September 22, 2014. Its central goal was to understand how Mars lost much of its atmosphere and, with it, the conditions that once allowed liquid water to exist on the surface.
The spacecraft examined Mars’s upper atmosphere and ionosphere, measuring how solar wind and solar radiation interact with atmospheric gases. Those processes can strip hydrogen, oxygen, and other volatile material into space. MAVEN’s observations showed that atmospheric escape increases during solar storms and helped connect modern atmospheric loss with Mars’s transformation into a cold, dry world.
MAVEN is easy to confuse with Mars Odyssey, another NASA orbiter, but Odyssey’s major roles include mapping the surface and relaying communications. Cassini studied Saturn, while Galileo studied Jupiter. The name “maven” also means an expert, but here it is chiefly an acronym for the Mars mission.