Re-entry predictions of space objects and impact on air traffic

Abstract. This work focuses on predicting the re-entry of an uncontrolled re-entry vehicle (RV) and how this affects air traffic. It includes the propagation of the nominal trajectory and that of the fragments resulting from the breakup of the object. The breakup does not occur at a fixed altitude but is a consequence of the thermal and dynamic loads acting on the RV as it re-enters the atmosphere. The purpose of the analysis is to identify a dangerous area at specific heights (flight levels) to be evacuated in time for air traffic. The hazard area is defined as that which includes all the impact points of the fragments at this altitude taking into account the additional safety margins. The study also considers the presence of uncertainties affecting the initial state of the vehicle. Accordingly, a Monte Carlo analysis is performed to predict the worst-case scenario and to better estimate the hazard area. Once the area has been defined, an evacuation algorithm calculates, for each aircraft, the trajectory changes necessary to clear or avoid the zone over time.