Martian upper atmospheric variability observed by MAVEN/NGIMS in response to space weather events in view of M-MATISSE mission

Observations of the Martian upper atmosphere over the past several decades, from both Earth-based telescopes and Mars-orbiting spacecraft, have revealed a highly dynamic system strongly influenced by solar forcing. Variability driven by space weather events such as solar flares, solar energetic particle (SEP) events, and coronal mass ejections (CMEs) plays a crucial role in controlling the structure, composition, and escape of the Martian atmosphere. However, important uncertainties remain regarding the magnitude, altitude extent, and temporal evolution of these responses.

A major advance in our understanding of the Martian upper atmosphere and its plasma environment is expected from M-MATISSE, an ESA Medium-class mission candidate currently in Phase A. The M-INEA instrument, a neutral and ion mass spectrometer within the M-EPI plasma suite onboard M-MATISSE, is designed to investigate the coupling between neutrals, ions, and the solar wind, and to quantify processes leading to atmospheric escape.

In support of defining the scientific requirements of M-INEA, we use the observations from the Neutral Gas and Ion Mass Spectrometer (NGIMS) onboard the MAVEN spacecraft. We characterize the response of the Martian upper atmosphere and ionosphere on short- and long-term variations during selected space weather events. The analysis focuses on identifying typical variability levels, event-driven enhancements, altitude dependence, and orbit-to-orbit variability, providing constraints on sensitivity, dynamic range, and temporal resolution required for future measurements.