Optimisation of Lunar descent trajectories with Direct Methods

The rising interest in Moon exploration is demanding for an improvement of many technologies in the space industry. New missions will require precise landing capabilities and robust software and hardware able to cope with the uncertainties and difficulties that landing on Earth’s celestial satellite implies. While for the Apollo program relied on the eyesight of the astronauts and manual control, today everything must be autonomous. New Guidance, Navigation and Control systems must be developed, able to operate without human direct intervention, with a soft approach while satisfying plenty of restrictions required for safe operations. Its important to remember that the landing conditions may change in real time, and that’s why new technologies must be able to detect these changes and adapt the trajectory consequently. This will increase fuel consumption and therefore it becomes critical to have the optimal trajectory that guaranties the maximum possible landing mass as a guide for the GNC. In this thesis, developed at Thales Alenia Space in Turin, a direct optimization method is used to obtain the optimal descent trajectories that will lead to the highest value of landing mass. In order to achieve this goal a Matlab algorithm has been created relying in particular on two functions, fmincon and multistart. Later, a trade off between four different architectures has been made in order to find the most suitable configuration for the mission.