Evaluation of scientific performance of JEM-EUSO mission with Space-X Dragon option

International audienceExtreme Universe Space Observatory on-board the Japanese Experiment Module (JEM-EUSO) is a mission devoted to the observation of ultra-high energy cosmic rays (UHECRs) around and above the Greisen-Zatseptin-Kuzimin energy at ∼ 5×10$^{19}$ eV. The origin of these enigmatically energetic cosmic rays remain an open question since their discovery more than 50 years ago. High statistics on UHECRs are essential to provide key information to answer this question and necessitate very large exposures to overcome their extremely low flux of an order of a few events per square kilometer per century. JEM-EUSO is designed to measure the air showers induced by UHECRs using a super-wide field-of-view ultra-violet fluorescence telescope pointed downwards on Earth’s nighttime atmosphere. Orbiting onboard the International Space Station (ISS), JEM-EUSO rather uniformly covers the entire Celestial Sphere, allowing a thorough analysis of the UHECR arrival direction distribution. In the present work, we introduce a design of the JEM-EUSO telescope suitable for using the Space-X Falcon 9 rocket and the Dragon spacecraft for transport to the ISS. This design allows for accommodation of the telescope with equivalent or slightly improved performance than that studied for H-II Transport Vehicle option. We then discuss the expected performance, in particular the scientific objective of searching the arrival direction distribution of UHECRs for their origin through simulation studies