Conceptualization, design & simulation of a small asteroid probe

The Asteroid Impact and Deflection Assessment (AIDA), is an upcoming mission resulting from the collaboration of ESA and NASA and aims at assessing the effects of a kinetic impact on an asteroid for the purpose of threat mitigation. In this framework, this research seeks to prove the feasibility of a small lander design able to autonomously land on the secondary object of the asteroid system Didymos. Initially, an overview of the most suitable guidance laws and sensors is provided. This highlighted that some types of proportional navigation guidance laws and the ZEM/ZEV could be good candidates and are therefore further analyzed in the following chapters. Meanwhile, a set of sensors comprising altimeter, camera, Star-Tracker and accelerometers was considered. To assess the effect of the noise affecting the sensors on the translational dynamics of the probe, the system is linearized and studied. This permitted to highlight that the most relevant disturbances are the ones that affect the determination of the LOS rate, hence the readings of camera and star-tracker. Afterward, the deployment is simulated in the details in a simulator, this permitted to determine that a combination of a modified version of the true proportional navigation and ZEM/ZEV provide a good solution in terms of guidance laws. Unfortunately, because of the lack of details characterizing the asteroid model, it was not possible to realistically simulate the ZEM/ZEV. Therefore, it is suggested as the next step of study to carry out further investigation and to develop a simulator able to reach the depth of details required. Finally, a proposed set-up of sensors is delineated and a Monte-Carlo run analyzing the robustness and reliability of this design for the MTPN is reported. The outcome seems to demonstrate that with a very compact and simple design, the probe is capable to autonomously insert itself in a trajectory leading from the deployment location to the target asteroid.