Launched on 18 November 2013, the MAVEN spacecraft (Mars Atmosphere and Volatile EvolutioN) is aiming to find out how most of Mars’ atmosphere was stripped away.

Why is the atmosphere of Mars, once dense and probably rich in water and carbon dioxide, today so tenuous? This is the enigma the MAVEN spacecraft is attempting to solve after entering orbit around the Red Planet on 22 September 2014, 10 months after launch, in an effort to retrace the history of its atmosphere and climate. MAVEN explores Mars’ upper atmosphere and analyses how it interacts with the Sun and the solar wind, acquiring measurements from its 4½-hour elliptical orbit, at altitudes varying from 150 km to 6,000 km. It flies also a series of ‘deep dips’ into the upper atmosphere, as low as 125 km from the planet’s surface, to measure its composition. To accomplish all of these tasks, MAVEN is carrying a suite of eight scientific instruments.

Undertaken in partnership with France, MAVEN is a mission of NASA’s Mars Scout programme. CNES oversaw instrument development by French research laboratories. In particular, IRAP (Institut de Recherche en Astrophysique et Planétologie) in Toulouse developed and supplied the Solar Wind Electron Analyzer (SWEA), one of MAVEN’s eight instruments. The mission is scheduled to run for one Earth year, with an option to extend it to one Mars year (686 days).