The flight scheduling process is briefly described in the article. It is one of the most important stages of space flight control task solution. Three stages of flight scheduling are given: strategic, tactical and executive. The result of each scheduling phase is presented by special plan type: on-orbit operation summary, weekly lookahead plan, short-term plan. The difference of these plan types is in planning interval and data processing depth. The mathematical modeling of all required data and restrictions is made. A crew downtime minimization is the selected optimization criterion. Modified genetic algorithm for decision of assigned task is designed. The future tasks regarding crew activities scheduling process optimization are defined  

Keywords: scheduling, flight operation, crew activities, optimization, mathematical modeling, genetic algorithm