The Mars Exospheric Neutral Composition Analyser (MENCA) experiment was one among the five experiments onboard the Mars Orbiter Mission (MOM), the first Indian Mars mission. MENCA is a quadrupole mass spectrometer based scientific payload, capable of measuring relative abundances of neutral constituents in the mass range 1 to 300 amu, with unit mass resolution. In addition to acquiring the mass spectra in a specified mass range, the instrument had a provision to track the time variation of the abundances of a set of selected species. The primary science goal of MENCA was the in-situ measurement of composition of neutral species in the Martian exosphere, and to examine its spatial and temporal and variation. The observation from MENCA are vital in understanding the escape of the Martian atmosphere. The major findings from MENCA include

• First Observations altitude profiles of the three major constituents, CO2, N2 +CO, and O) in the Martian exosphere during evening hours (close to the sunset terminator)
• Suprathermal Argon atoms in the exosphere of Mars
• Expansion of Martian thermosphere during the Planet Encircling Dust Storm Event (PEDE) in 2018.