A mission planning tool design for re-entry:

A transition through the Earth's atmosphere is inevitable if it is desired to bring or return something useful from space. The transition is also known as the atmospheric entry, which is characterised by a highly energetic vehicle. Three types of entry can be distinguished: ballistic, glide and skip entry. In the hypersonic transition of a glide entry, the heating and structural loading can become severe enough to damage the vehicle and/or the crew. The attitude of the vehicle has to be controlled to avoid this. In addition, the vehicle should target an interface with the TAEM phase. During which the vehicle is aligned with the runway. The process of determining the attitude throughout entry is called mission planning. For on-board mission planning, simplifications need to be made on the vehicle, its environment and the flight dynamics to achieve an acceptable computation speed. As a consequence, the real trajectory will deviate from the planned trajectory. The trajectory tracker has the task to steer the vehicle towards the planned trajectory. The combination of a planning and tracking algorithm forms a guidance algorithm. The main question of this thesis work is formulated as: Is it possible to design an on-board executable guidance algorithm, for the hypersonic transition phase, which safely targets the TAEM interface? Four tasks have been derived from this question: simulator development, planning algorithm design, tracking algorithm design and guidance algorithm testing. The simulator serves as a test bed for the guidance algorithm. In the development of this software, a systems-based approach is taken with respect to the vehicle and its environment modelling. The advantage is that the software has a clear modular structure and it becomes easy to extend the simulator with new capabilities. The design of a trajectory planner has been decomposed into an angle of attack and bank angle planner. The angle of attack planner operates on the assumption of an equilibrium-glide trajectory. The bank angle planning algorithm is centered around an iterative search for a drag profile that corresponds to an estimated trajectory length travelled between entry and TAEM interface point. By incorporating the bank angle planning and tracking algorithms in one guidance algorithm, the main question is answered positively. The algorithm executes fast enough for an on-board implementation.