GNC technologies for NEO missions

Compared to planetary landing missions that have been already widely studied in the past years, the design of missions to small bodies is still an open field for innovation. This is especially true for the Guidance, Navigation and Control system (GNC) for which the particular environment of Near Earth Objects (NEO) both constrains the requirements and allows some flexibility in the design.Focusing on the Marco Polo mission, the autonomy and GNC requirements are derived from mission needs. A descent scenario is proposed and the guidance strategy is described. Candidate navigation solutions (for both relative and absolute navigation) are introduced, coming from past and on-going technology development projects, and a possible baseline is highlighted.