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Non-Destructive Damage Detection of Spacecraft Thermal Protection System with ISAR Imaging

The thermal protection system (TPS) ensures the flight safety of the high-speed spacecraft. However, different degrees of damage are unavoidable during the flight missions. In this paper, a nondestructive detection of on-orbit spacecraft TPS with ISAR imaging technology is proposed. The TPS with micro-damage structures such as cracks, debonding, warpage, holes etc. are modeled, the corresponding Ka- and W-band backscattered electric field data are simulated, and finally the ISAR two-dimensional images are generated with the back projection algorithm. The experimental results have well verified that ISAR imaging can effectively achieve high-precision images of the damaged thermal protection structures. Thus, through the real-time ISAR imaging of targets such as space stations from accompanying satellites, the possible damage types and damage locations can be monitored and displayed to achieve nondestructive detection of TPS and to evaluate the flight safety.