ABSTRACTOver the past 25 years, we have witnessed the extraordinary achievements of both robotic and manned space missions. A key element in the success of these missions has been the development of the navigation systems that have enabled the determination of current and predicted spacecraft position and velocity to the accuracies required to meet mission objectives. This paper presents an overview of space navigation systems, navigation techniques, and capabilities for robotic and manned mission applications for the past 25 years. Robotic navigation system data types, information content, and navigation data processing techniques are reviewed. Application of these systems to planetary missions is discussed, with emphasis placed on the Voyager mission. For manned space navigation systems, the role of on‐board and ground navigation capabilities is presented. Key technology developments that enabled the development of on‐board systems are discussed. Ground and on‐board navigation data types and their information content, data processing techniques, and system operations are reviewed. Application of these ground and on‐board systems to Apollo, Skylab, Apollo/Soyuz, the Space Shuttle, and the Space Station is described. Finally, a look at the future of space navigation is presented. The application and extension of current navigation concepts and of new navigation‐enhancing technologies to the future requirements of robotic and manned space navigation systems are