Abstract <p>An important task and logical conclusion of the work of the ground–space project RadioAstron was the creation of a complete Project Data Archive, which ensures storage and organized access to all scientific and service information obtained during the experiment. The data archive is unique and allows reprocessing of data when new ideas and calculation algorithms appear. The data archive includes a database that allows one to navigate this information and to carry out selection and statistical studies. This article describes the information content of the RadioAstron Project Data Archive and hardware and software complex. The web interface allows the researcher to interact with the database. The web interface includes several sections and allows one to create one’s own pages for user requests. The data archive is a developing system, which in the future may become part of the Space Missions Data Center.</p>