A scientific protocol concerning joint experiment by means of the developed orbital telescope onboard the Russian segment of ISS is signed between SINP MSU and Japan Institute RIKEN. The document contains the objectives of the project, principles of data exchange and joint publications, and parties' responsibilities. This protocol provides a basis for the further cooperation between Russia and Japan within the frames of K-EUSO project, but at the level of space agencies - Roscosmos and JAXA.