The training manual describes the methodology and tools for creating onboard spacecraft control systems based on network computing systems. The technology of development and development of software for spacecraft control systems is presented, including the main provisions on methods and means of modeling onboard spacecraft systems. Methodology of modular design of structure of software and information support of on-board control systems and use of real-time operating systems in on-board computer systems is considered. The content of this manual corresponds to the course of lectures given by the author at the Bauman Moscow State Technical University at the Department of Automatic Control Systems.