Section: Application Domains
In the framework of a long-term partnership with the Cnes, and more recently Astrium, we have studied trajectory optimization for space launcher problems. This kind of problems typically involves hard constraints (thermal flux, mechanical efforts) and inexact models (atmosphere, aerodynamic forces). The two main achievments were to study when singular arcs may occur, and to show the effectiveness of a HJB approach on a reduced model. Singular arcs are flight phases with a non-maximal thrust, induced by a tradeoff between speed and atmospheric drag; they cause difficulties of both theoretical and practical nature. The latter point is the first step in the process of applying global methods to this class of difficult problems.