  Reliability assessment in concerned with the analysis of devices and systems
whose individual components are prone to fail. This reliability analysis
documents the process and results of reliability determination of the JEM-EUSO
photomultiplier tube component using the methods 217 Plus. Quantum efficiency
degradation and radiation hardness assurance. In conclussion, the levels of
damage suffered by the PMTs which comprise the focal surface of JEM-EUSO Space
Telescope, are acceptable. The results show as well the greatest contribution
to the failure is due to radiation SET. The guaranteed performance of this
equipment is a 99.45 per cent, an accepted value of reliability thus fulfilling
the objectives and technological challenges of JEM-EUSO.
