The M-MATISSE mission: Mars Magnetosphere ATmosphere Ionosphere and Space weather SciencE. An ESA Medium class (M7) candidate in Phase-A

The "Mars Magnetosphere ATmosphere Ionosphere and Space-weather SciencE (M-MATISSE)" mission is an ESA Medium-class (M7) candidate currently in Phase A study by the European Space Agency (ESA). M-MATISSE's main scientific goal is to unravel the complex and dynamic couplings of the Martian Magnetosphere, Ionosphere, and Thermosphere (M-I-T coupling) with relation to the solar wind (i.e., space weather) and the lower atmosphere, and the processes leading to this coupling, which are highly entangled between several regions of the system. The M-I-T coupling controls the dissipation of incoming energy from the solar wind, and therefore, the evolution of Mars' atmosphere and climate (including atmospheric escape, auroral processes, and incoming radiation). Moreover, understanding the behavior of Mars' M-I-T system and of the chain of processes that control space weather and space climate at Mars, as well as the radiation environment, is essential for exploration as it leads to accurate space weather forecasts and, thus, prevents hazardous situations for spacecraft and humans.

M-MATISSE consists of two orbiters with focused, tailored, high-heritage payloads to observe the plasma environment from the surface to space through coordinated simultaneous observations. It will utilize a unique multi-vantage point observational perspective, with the combination of in-situ measurements by both orbiters and remote observations of the lower atmosphere and ionosphere by radio crosstalk between them. The father-ship, called Henri, has a periapsis below 270 km and an apoapsis of 3000 km with an inclination of 60°. It is intended to spend most of its time within the Martian plasma system. The daughter-ship, called Marguerite, also has an inclination of 60°, a periapsis below 270 km and an apoapsis of 10,000 km. It is intended to spend most of its time in the solar wind and/or far tail of Mars (a region barely explored before). M-MATISSE has a nominal mission duration of 1 Martian year, and the launch date is identified for July 2037.

The M-MATISSE mission has three main goals:

Characterizing the global dynamics of the M-I-T coupling by unravelling its temporal and spatial variabilities. This will be done with simultaneous observations of the solar wind (energy input) and ionosphere-magnetosphere (energy sink), and also, via investigating the coupling of the mesosphere with the ionosphere and solar energetic particles.

Characterizing the radiation environment by determining how the M-I-T system absorbs the energy that reaches the planet and forecasting near-real time planetary space weather.

Characterizing the ionosphere/lower-atmosphere coupling, which is a region barely explored but essential for solar energetic particles related phenomena as well as for communications in HF wavelengths.

In addition, M-MATISSE will significantly contribute to the understanding of Mars climate and the lower atmosphere as two remote instruments have dedicated instrumentation to monitor dust, clouds, and to obtain temperature and density profiles from the surface up to about 50 km. Moreover, the heliophysics community will be involved in the mission with a full-package solar wind monitor at Mars' distances, contributing to the understanding of solar wind and the propagation of solar transients in the inner solar system.