JEM-EUSO

JEM-EUSO is an international telescope project to be placed on the International Space Station, looking at the Earth at an altitude of 400 km with an aperture such that a circle of 500 km in diameter is observed by means of UV light emitted by the fluorescence of nitrogen from the air excited by the sheaves induced by cosmic rays of energy greater than 1020 eV.

The JEM-EUSO mission, aboard the Japanese module of the International Space Station, is dedicated to the observation of the ultra-high energy of cosmic rays (UHECRs) through the detection of UV light associated with giant air flows that they induce in the Earth's atmosphere. The telescope is composed of:

• a wide-field optics based on Fresnel lenses, to cover an area of about 2,105 km2 in the field, in nadir mode, much wider than the UHECR experiments on the ground.
•  a surface at the point of focus with a very large number of very sensitive photodetectors.