Pointing Error budget analysis for the INNOVATOR mission

This thesis presents the development of the INNOVATOR pointing error model using the Pointing Error Engineering Tool (PEET) within the framework of Phase B. The objective of this work is to extend the preliminary pointing error budget established in Phase A into a comprehensive model that accounts for the contributions of the Attitude Determination and Control System (ADCS), spacecraft dynamics, and sensor performance. The model follows the ECSS pointing error engineering methodology and simulates the propagation of different error sources through a closed-loop ADCS architecture. Two distinct approaches are implemented for the estimation of the Attitude Knowledge Accuracy (AKA). The first follows the simplified sensor fusion methodology used during Phase A, combining the individual sensor accuracies through a weighted formulation. The second introduces a geometry-aware approach based on the linearized formulation of Wahba’s problem, allowing the influence of sensor measurement geometry on the final pointing accuracy to be evaluated. Furthermore, performance is assessed under two critical operational conditions: eclipse and sunlit scenarios. The results indicate that the spacecraft pointing performance strongly depends on both sensor availability and measurement geometry. In particular, the absence of the Sun sensor during eclipse conditions significantly increases the pointing error, while favorable sensor geometry improves the attitude estimation accuracy. The developed PEET model successfully reproduces and validates the Phase A pointing budget while providing a robust framework for analyzing spacecraft pointing performance in subsequent design phases.