The JEM‐EUSO Mission

Abstract

The JEM‐EUSO mission explores the origin of the extreme energy cosmic rays (EECRs) above 100 EeV and explores the limits of the fundamental physics, through the observations of their arrival directions and energies. It is designed to achieve an exposure larger than 1 million km2 sr year at the highest energies to open a new particle astronomy channel. This super‐wide‐field of view (60 degrees) telescope with a diameter of about 2.5 m looks down from space onto the night sky to detect near UV photons (330–400 nm, both fluorescent and Cherenkov photons) emitted from the giant air showers produced by EECRs. The arrival direction map with more than five hundred events after just the three years will tell us the origin of the EECRs, allow us to identify the nearest EECR sources with known astronomical objects, which can afterwards be examined in other astronomical channels. This is likely to lead to an understanding of the acceleration mechanisms perhaps producing discoveries in astrophysics and fundamental physics. The comparison of the energy spectra among the spatially resolved individual sources will help to clarify the acceleration/emission mechanism, and also finally confirm the Greisen‐Zatsepin‐Kuz’min process for the validation of Lorentz invariance up to γ∼1011. Neutral components (neutrinos and gamma rays) can be detected as well, if their fluxes are high enough. The JEM‐EUSO mission is planned to be launched by a H2B rocket about JFY 2016 and transferred to ISS by H2 Transfer Vehicle (HTV). It will be attached to the Exposed Facility external experiment platform of “KIBO.” JEM‐EUSO is being developed by an international collaboration of institutions from 13 countries.