Optimizing geostationary station-keeping underconstraints

Sammanfattning

This thesis presents the development and implementation of new station-keeping strategies forgeostationary satellites under operational constraints, with a particular focus on collision avoidance.The work was carried out within Airbus Defence and Space, in the Flight Dynamics, Mission Analysisdepartment, using the in-house java-based software Quartz. A reviewof current collision assessmentmetrics was conducted, highlighting the limitations of classical probability-based methods in GEO andthe operational relevance of geometrical thresholds. Building on this state of the art, a new collisionconstraint feature was implemented within the station-keeping module for GEO satellites. It should benoted that collision avoidance and station-keeping are typically two distinct activities that often conflict,whether in terms of scheduling or propellant consumption. Thestrength of this work lies in combiningboth to optimally resolve these conflicts. The effectiveness of the geometrical thresholds was evaluatedthrough theoretical and operationally-inspired test cases, including longitude drift and inclinedapproaches, using low-thrust electric propulsion models. Results demonstrate that the integration ofcollision constraints within station-keeping algorithms can increase safety while maintaining fuelefficiency within acceptable limits. This contribution provides a step towards more autonomous androbust flight dynamics tools for long-term GEO operations.