The paper deals with the problems of medical and ecological escorts of space rocket-making activities. The properties of one of the highly toxic components of propellant - asymmetric dimethylhydrazine as a substance assigned to a class of ecological toxicants, are considered. The data obtained on implementing the program for a study of the health status in the population living not far from the asymmetric dimethylhydrazine-polluted areas are presented. The authors propose to consider a package of measures that can apply the systems approach to securing the safety of the population to live and work in areas under space-rocket making activities, which is based on the prevention principle provided by the Rio de Janeiro Environment and Development Declaration.