Extreme energy cosmic rays. Observation of the atmospheric fluorescence from the ISS

From a Low Earth Orbit (LEO: 400-1000 km of altitude) the light due to cosmic rays of extreme energy showering in a huge mass of atmosphere, up to 2-3 x 1014 t, can be registered. This makes it possible to approach fields of Fundamental Research in Cosmology and in Astro particle Physics up to now out of reach of the experimental observation, making also the vast field of Physics of the Atmosphere available to the exploration. The full coverage of the whole observable air mass from a LEO requires to cover a Field of View (FoV) of 1300-1400 by composing separate modules, each covering a smaller FoV. The ISS is the most suitable vehicle where those modules, each covering a smaller FoV. The ISS is the most suitable vehicle where those modules could opens the possibility of a gradual realization of the full coverage, and a technically evolving approach: the optical system could be regarded as a permanent facility on board (or co-flying with) the ISS for observing the Earth surface in optical an near-optical wavelengths: different sensors could be alternated on their foci to meet the needs of different experiments or services. The missions currently under study can be the starting pieces for a full coverage facility. Besides the EUSO mission, separately described in a dedicated talk, the situation of the ongoing studies will be reported