Landing trajectories analysis and geophysics of Juventas in the binary asteroid system Didymos

On February 15, 2013, a 20m meteor exploded over Chelyabinsk, Russia, generating a flash brighter than the sun and creating a shockwave injuring 1,500 people. The blast was so strong that it yielded 26 to 33 times as much energy as the Hiroshima atomic bomb. This incident was a reminder of the importance of monitoring near- Earth objects and having planetary defense systems. Astronomers have estimated that there are tens of thousands of near-Earth objects of more than 140 meters that could cause regional devastation if they hit Earth. In this context, the Asteroid Impact and Deflection Assessment (AIDA) mission jointly led by NASA and ESA is part of humanity’s planetary defense mission to attempt the first ever deflection of a celestial body in the solar system. The Double Asteroid Redirection Test (DART) spacecraft developed by NASA and the Johns Hopkins Applied Physics Laboratory will slam into the moon of the binary asteroid 65803 Didymos to shift its orbit. Five years later the Hera spacecraft developed by ESA will study the impact caused by DART and one of Hera’s additional landers, the Juventas CubeSat, will attempt to land on the asteroid. This thesis focuses on the landing phase of the Juventas CubeSat to study a set of reliable landing trajectories. The dynamical environment of the CubeSat in the Didymos system and the landing phase are first presented. A numerical integrator to efficiently compute landing trajectories is proposed and studied. A braking maneuver during the descent is implemented and shape models are added to represent the asteroid. The interaction with the surface of the asteroid is also modeled. Finally, a Monte Carlo analysis to study the robustness of the found landing trajectory is performed.