  M dwarfs show the highest rocky planet occurrence among all spectral types,
in some instances within the Habitable Zone. Because some of them are very
active stars, they are often subject to frequent and powerful flaring, which
can be a double-edged sword in regard of exoplanet habitability. On one hand,
the increased flux during flare events can trigger the chemical reactions that
are necessary to build the basis of prebiotic chemistry. On the other hand,
sufficiently strong flares may erode exoplanets' atmospheres and reduce their
UV protection. Recent observations of flares have shown that the flaring flux
can be x100 times stronger in UV than in the optical. UV is also preferable to
constrain more accurately both the prebiotic abiogenesis and the atmospheric
erosion. For these reasons, we are developing a CubeSat payload concept to
complement current flare surveys operating in the optical. This CubeSat will
observe a high number of flaring M dwarfs, following an all-sky scanning law
coverage, both in the UV and the optical to better understand the different
effective temperatures as wavelengths and flaring status go. This will
complement the bright optical flares data acquired from the current
ground-based, high-cadence, wide FoV surveys. Another scientific planned goal
is to conduct few-minute after-the-flare follow-up optical ground-based
time-resolved spectroscopy, that will be triggered by the detection of UV
flares in space on board of the proposed CubeSat. Finally, the study of M
dwarfs stellar activity in the UV band will provide useful data for larger
forthcoming missions that will survey exoplanets, such as PLATO, ARIEL, HabEx
and LUVOIR.
