The TUS space experiment: calibration in flight

The TUS space experiment is aimed to study the energy spectrum and arrival direction of Ultra High Energy Cosmic Rays (UHECR) at E ~ 1020 eV by measuring the fluorescence yield of EAS in the atmosphere. The "Lomonosov" satellite, with TUS, was launched at the April 16, 2016. Satellite now is in orbit and fully operational. The TUS collaboration plans to design and produce a ground-based system of light sources for the in-flight calibration of the TUS detector. Two types of the possible UV light sources are presently under consideration for this purpose: LEDs and laser stations. The design and fabrication of the TUS ground-based calibration light source prototypes based on LedEngin-LZ4-00U600 LEDs and on the use of the "Simeiz-1873" laser stations are presented.