Space debris has become a rising problem in the aerospace community, leading to the need for effective spacecraft collision avoidance processes. Currently, these processes can be called unilateral as only one object in conjunction is considered maneuverable. This thesis focuses on the implementation of a combined action approach to collision avoidance and proposes a cooperation process between operators. The research objective is to optimize the dual maneuver solutions and explore negotiation proposals within a Space Traffic Management system.

The study utilizes an optimization algorithm based on multiple objectives, including propellant mass consumption, collision probability, and mission disturbance. The decision variables used in the optimization are related to the three-direction maneuvering within both objects in conjunction. The optimization is first carried out to minimize the three objectives listed above. These optimization results are considered preliminary as they do not allow for a proper trade-off for the operators. Hence, a review of the objectives used in the optimization algorithm yields the two new criteria used for the final results: the Collision parameter and the Cost parameter. The latter combines propellant mass consumption and mission disturbance.

The results, displayed as Pareto fronts, demonstrate that these objectives allow for the identification of optimal maneuver solutions. Adding on, a sensitivity analysis highlights the importance of precise maneuver timing and lower ΔV contributions within the solutions. The operator is recommended to re-analyze the CAM if the maneuver timing varies by more than 5 minutes. Through the exploration of various study cases and scenarios, insights are provided into the interaction between different systems in space. In general, the chaser showed higher values of ΔV magnitude than the target but the optimization results showed that both interacted together to reach the collision avoidance solution. The I_sp factor proved to not affect the optimization results significantly, and the single maneuvering spacecraft scenarios were successfully solved with the optimization method. This scenario led to higher Cost parameters and higher Collision parameter, the P_c could only be lowered slightly further than 10^-10. As this is below the defined threshold, the results were accepted.

In addition, a proposal is drafted for a communication flow and cooperation framework. The Middle Man, acting as a central authority between the two parties, facilitates the cooperation process, ensuring fair and efficient collaboration between operators. The proposed framework for decision-making is called "rule and resource following shared approach". While specific rules and procedures are not defined in this thesis, the framework allows for them to be included once agreed upon by operators. This thesis concludes that the proposed combined action and cooperation process offers potential solutions to the challenges posed by space debris and contributes to the safety and sustainability of space activities.