G. Marcoff, Marco Keywords: Space | Space law | Sources of law | Mots clefs: Espace cosmique | Droit cosmique | Sources | ABSTRACT Marco Marcoff explains in the introduction to his course that the formation of the customary rules of international space law during the pre-conventional stage of its elaboration as well as the quasi-conventional and quasi-legislative process established in the United Nations system suggestively show the contemporary tendencies affecting the process of creating international rules, and more…