Skip Re-Entry Trajectory Detection in AeroAssisted Orbit Transfer

This paper analyzes the problem of excessive energy dissipation caused by uncertainties in the near-Earth aero-assisted orbit transfer (AOT) missions, and proposes an abnormal trajectory detection method. To employ aerodynamics for orbit transfer, the space vehicle will reentry to the atmosphere, change orbit inclination assisted by aerodynamics and fly back to the atmospheric exit window. If the energy is excessively dissipated, supplementary energy is needed, or the mission will fail. To detect the possible energy deviation in actual flight, the nominal trajectory is analytically estimated on the basis of the aerodynamic characteristics of the vehicle, which shows to be accurate enough under the "Karman line". Depending on energy deviation, two abnormal modes are identified which correspond to that the vehicle can leave the atmosphere but can’t arrive at the target orbit, and that the vehicle can’t leave the atmosphere, respectively. The deviation thresholds in term of altitude are established, including noises and the required detection probabilities. Test cases show that the proposed algorithms can support anomaly detection up to the expected probability, and help the vehicle continue the orbit transfer mission, or transfer to an emergency orbit, depending on the level of deviation and available energy reserve.