Combined Communication and Navigation Systems to Explore Celestial Bodies

Communication and Navigation are fundamental functions in every space exploration missions. In case of repeated exploration of a solar system body, either a planet or a lune, the recurring request for these functions suggests to introduce more effective systems. The solution can be provided by satellite constellations providing both functions, i.e. helping with navigation and allowing for a data relay to the Earth. Such a choice, relieving the single explorer to operate autonomously, becomes even more interesting as exploration evolves towards exploitation of the celestial body resources. The paper analyses the characteristics of the combined, possible solutions for different targets of the solar system. The focus is initially on the orbital design for the space segment of the systems, then includes basic considerations for the technical aspects of navigation and communication functions. The description of main aspects to be dealt with while designing these infrastructure for the solar system exploration opens the path to interesting considerations about the convenience, feasibility and reliability of the solutions.