Parameterised Laws for Robust Guidance and Control of Planetary Landers

Planetary descent and landing on small planetary bodies are very scientifically rewarding exploration missions but also very challenging from an engineering perspective. This is mostly due to the perturbed and poorly known (physical, gravitational and magnetic) characteristics of the bodies, but also as demonstrated by the European Rosetta mission by the long-time degradation effects of the spacecraft subsystems. In order to address this challenge, the Space community has recognised the need to use robust spacecraft guidance and control algorithms. Of particular relevance, the newly-developed structured Hinfinity design and tuning framework is specially suitable for industry-oriented applications. Specifically for the aforementioned type of Space missions the availability of a fixed GNC architecture coupled with the use of a methodological tuning process and tools is considered a very desirable axis for improvement. In order to apply this GNC tuning advanced tools a structural framework well connected with the industrial state-of-practice and legacy knowledge is required. This paper presents such a parameterised structure for the small planetary bodies’ descent and landing exploratory missions, and shows that it reconciles the state-of-the-art in closed-loop guidance techniques.