UNIPD space debris impact detector applications: from space insurance to safeguarding the space debris environment

The increasing congestion of the near-Earth orbital environment makes space debris a major threat to the sustainability and reliability of space missions. While large objects can be tracked and considered in collision avoidance strategies, non-trackable debris still represents a critical risk, since even millimetre- or sub-millimetre-sized particles can damage spacecraft surfaces, structures, and internal components. In this context, impact sensors can provide valuable in-orbit information on the actual interaction between a spacecraft and the debris environment. This thesis investigates the use of data provided by a space debris impact sensor developed at the University of Padua to support spacecraft damage assessment and risk modelling. The sensor detects impacts caused by non-trackable debris and can provide information on the occurrence of the event, the impacted area, and, depending on its capability, additional impact characteristics. Starting from these data, a damage modelling framework is developed by combining debris environment models, spacecraft architecture, component vulnerability, and Ballistic Limit Equations, which are used to relate impact conditions to penetration, failure, or non-catastrophic damage scenarios. The proposed model is applied in two complementary fields. The first is space insurance, where the physical damage caused by debris impacts is translated into a financial payout and used to support the calculation or update of a collision insurance premium. In this framework, the integration of sensor data reduces the uncertainty on the actual loss and improves the estimation of the payout distribution. The second application concerns the update of the Environmental Consequences of Orbital Breakups index developed at Politecnico di Milano. Impact sensor data and the associated damage model are used to refine the real-time assessment of the spacecraft health state and to update the probability of explosion or fragmentation through a weighting factor applied to a baseline statistical probability. This enables a dynamic evaluation of the environmental criticality of the spacecraft. Real-time ECOB estimation can also support operational decisions during the mission. If the updated explosion probability or environmental criticality exceeds a predefined threshold, mitigation actions could be considered, such as transferring the spacecraft to an orbit where a possible fragmentation would have lower environmental consequences. This approach is also relevant for the SustainSat concept developed at New Horizon, with which this thesis is carried out in collaboration. SustainSat aims to convert spacecraft telemetry data into real-time environmental indicators, and the proposed impact-sensor-based damage modelling could extend this capability by linking detected debris impacts to dynamic environmental risk assessment.