The method of endogenous forecasting of the evolution of the age structure and the total number of scientific personnel on the national scale (or a sufficiently large and self-sufficient academy of science) proposed by the authors is described in detail, which allows to determine the indicators that can serve as benchmarks in the formation of policy aimed at creating or reviving the scientific potential of the state. It is used to trace the main trends in the dynamics of the research corps in Ukraine, Russia and Belarus, to assess the real prospects for its increase and bringing it within the next decades to the level of scientific support of innovative development of the economy, typical for European countries, as well as the possibility of optimizing the age structure of scientific workers.