Mars ascent vehicle preliminary design

This thesis work is focused on the determination of a preliminary design of a Mars Ascent Vehicle. The application area of this spacecraft is included in the Mars Sample and Return Program. The main objective of the Mars Ascent Vehicle is providing a way to lift the Martian samples from the surface to a specific orbit around the planet, where they can be captured and sent back to Earth to be analyzed. An important peculiarity of the Mars Ascent Vehicle is the fact that it is the only element in the Mars Sample and Return program which has never been built or tested before. It implies that the failure probability for this element is higher. For this reason, robustness in the design is a key requirement because a failure in the Mars Ascent Vehicle would compromise the whole mission. The great amount of variables and possible options makes mandatory to develop a simple model from which a conceptual design can be obtained. This design is then further improved. For this reason, the first goal of this thesis includes the development and optimization of this model in order to have a reduced amount of conceptual designs to work with in further stages. Careful attention is put on minimizing the gross lift off mass of the Mars Ascent Vehicle. The comparison of the designs is carried out taking into account the main requirements and constraints of the mission, as well as their own performance. From this comparison, a baseline option is selected and further developed. The conceptual baseline design is extended to a subsystem level. Special attention is focused on the structural design assuring no structural problems arise during the ascent phase while maintaining a reduced mass. The attitude control system is the other main subsystem sized in detailed in this work. It allows to determine the sensors and actuators needed to obtain the attitude 4 profiles required to the fulfillment of the mission objectives. The initial model and sizing of the attitude control system in this work have been developed using MATLAB and Simulink. For the structural analysis, finite element software as Nastran-Patran was employed.