The sixth wave of Ukrainian scientific emigration, which began at the end of February 2022, and the formation of new structures in the Ukrainian scientific diaspora have stimulated research on the study and preservation of Ukrainian scientific heritage abroad. However, such research and measures to preserve this scientific heritage will not be effective if they are not based on the concept and technologies of Open Access. Therefore, the aim of our study is to show how such research should be conducted, using the example of the analysis of staff composition at the Ukrainian Free University and its publication activity in its first five years of operation, as well as what general measures are necessary to study and preserve the scientific heritage of all six waves of Ukrainian scientific emigration. The article deals with the following issues: periodisation of the waves of Ukrainian scientific emigration; identification of Ukrainian scientific and educational organisations of the first wave of Ukrainian scientific emigration; brief history of the Ukrainian Free University; publication activity of the professors of the Ukrainian Free University (1921-1925) with the selection of works published in Open Access; linguistic biographical Wikipedia articles for the professors of the Ukrainian Free University (1921-1925); distribution of publications by professors from Ukrainian Free University through digital libraries and repositories; analysis of book marks using a case study; standards for describing works in electronic collections of rare and old publications; approaches to the development of the programme "Open Access to the Scientific Knowledge and Cultural Heritage of Ukrainian Scientific Emigration". Overall, the results of study shows the importance of preserving the continuity of the traditions established by the first waves of Ukrainian scientific emigration, the new generation of Ukrainian scientific emigrants should maintain these traditions. In order to study and understand these traditions, it is necessary to study the activities of scientists of previous waves of Ukrainian scientific emigration, and in order to make the results of this study available to the wider scientific community, they should be digitised and made publicly available.