The study aims to identify the features of reflecting the space mythologem in twentieth-century music art. The work examines the trend of cosmism in the musical creative work of composers of the last century, cosmists’ interpretations of the spatio-temporal properties of the world embodied in music. The scientific novelty of the study is determined by defining the main points in the development of the evolution process of the space mythologem in twentieth-century music art in the setting of the active exploration of the universe as an astronomical reality. The conclusion drawn is that the evolution of the space mythologem in twentieth-century music passes through several stages – from classical music to electronic music and film scores.