First ACT global trajectory optimisation competition results found at CNES/CS

This paper presents the solution of the CNES/CS joint team in response to the first ACT competition on global trajectory optimisation. The optimisation tools available at CNES and CS are based on a Lambert's problem formulation associated with a direct optimisation method, or on Pontryagin's maximum principle associated with decomposition–coordination and continuation–smoothing techniques. After a brief presentation of all these numerical methods, we propose a procedure for finding a solution of the ACT problem. The solution proposed by our team fulfills all the mission constraints and consists in a sequence of seven different swing-bys (three of the Earth, one of Venus, two of Jupiter and one of Saturn) before the encounter with asteroid 2001 TW229. All the characteristics of the trajectory are finally detailed in terms of duration, thrust arcs and altitude of pericentre.