Entry trajectory optimisation of hypersonic vehicle

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In this Bachelor Thesis, the reentry trajectory of a lifting body vehicle returning from a Low Earth Orbit is modelled, optimised and discussed. The document starts by reviewing the framework and challenges of the atmospheric reentry, as well as the opportunities arising from the new space activities. Later, a pointmass simulator that computes the reentry trajectory of the NASA’s spacecraft HL-20 is developed, allowing to model the descent path of the lifting body vehicle given the initial orbital conditions, the angle of attack and the bank angle. Later, the trajectory is optimised by means of two global optimisation algorithms, particle swarm and genetic algorithm, in order to fulfil two objectives, minimum manoeuvring time and maximum landing accuracy, while maintaining the thermal and structural integrity of the vehicle. Finally, the project discusses the results obtained, performs sensitivity analysis and argue the validity of the outcomes. The bachelor thesis shows that global optimisation algorithms are suitable to design the guidance of atmospheric reentry, providing a flexible solution to accommodate diverse objectives and design variables. In addition, it shows the influence in the trajectory of using angles of attack as a function of time, as opposed to descending with constant angles of attack, as well as the difference between using simple turns and S-turns. Finally, the project revises the sensitivity of the proposed goals with respect to the fuel consumed in the orbital braking manoeuvre.
Space vehicles, Atmospheric reentry, Trajectory optimisation, Modelling, Particle swarm, Genetic algorithms
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