NASA’s MAVEN spacecraft was the first mission dedicated to studying Mars’s upper atmosphere and its interaction with the solar wind. Its name stands for Mars Atmosphere and Volatile Evolution.
MAVEN entered orbit around Mars on 21 September 2014. It measures particles and fields in the upper atmosphere and exosphere, the outer region where atmospheric gases can escape into space. The mission’s measurements help explain how Mars changed from a warmer, wetter ancient world into the cold, dry planet observed today.
Solar wind and ultraviolet radiation can remove atmospheric particles, especially when a planet lacks a strong global magnetic field. MAVEN has shown that atmospheric escape is an important process in Mars’s long-term climate history. It also observes how dust storms and other lower-atmosphere events affect the upper atmosphere.
MAVEN is an orbiter rather than a lander or rover. Its observations complement surface missions by linking present-day atmospheric processes with evidence preserved in Martian rocks and terrain.