The aero-gravity assist maneuver is here proposed as a tool to improve the efficiency of the gravity assist as, thanks to the interaction with the planetary atmospheres, the angular deviation of the velocity vector can be definitely increased. Even though the drag reduces the spacecraft velocity, the overall υ gain could be remarkable whenever a high lift-to-drag vehicle is supposed to fly. Earlier studies offer simplified approaches according to both the dynamics modeling and the atmospheric trajectory constraints. In this paper a 3D dynamical model is adopted and a more realistic L/D performance for the hypersonic vehicle is assumed. Some relevant aspects related to the multidisciplinary design have been considered such as heating rates and structural loads bounding. Comparisons between in and out of plane maneuvering have been performed by assuming, as control variables, either the angle of attack or the bank angle, respectively. The optimal control problem has been solved by selecting a direct method approach. The dynamics has been transcribed into a set of non-linear constraints and the arising non-linear programming problem has been solved with a sequential quadratic programming solver. To gain the global optimum convergence the initial guess has been supplied by solving the same problem by a direct shooting technique and a genetic optimizer.

The lander Philae of the Rosetta mission landed on the surface of the comet 67 P/Churyumov–Gerasimenko on November 12, 2014. Among the specific subsystems and instruments carried on Philae, the sampling, drilling and distribution (SD2) subsystem had the role of providing in-situ operations devoted to soil drilling, sample collection, and their distribution to three scientific instruments. After landing, a first sequence of scientific activities was carried out, relying mainly on the energy stored in the lander primary battery. Due to the limited duration and the communication delay, these activities had to be carried out automatically, with a limited possibility of developing and uploading commands from the ground. Philae׳s landing was not nominal and SD2 was operated in unexpected conditions: the lander was not anchored to the soil and leant on the comet surface shakily. Nevertheless, one sampling procedure was attempted. This paper provides an overview of SD2 operation planning and on-comet operations, and analyses SD2 achievements during the first science sequence of Philae׳s on-comet operations

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In this work the dynamics of a manipulator arm is analyzed by Maggi’s formulation and by automatic development of the equations of motion. Two control strategies, that is an adaptive and a standard one, are taken into account in order to satisfactory perform pick and place maneuvers. Numerical simulations emphasize performance qualities and limits of the two choices and suggest a possible implementation of mixed control strategies.

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