Abstract:For space-based optical detection systems, there is usually a difference between actual on-orbit operational perfor-mance and designed requirements based on fixed scenarios. To assess the availability of space-based optical detection systems in different backgrounds, the radiation characteristics of aerial targets have been simulated using body radia-tion and atmospheric transmission models. The background radiation characteristics were also statistically analyzed. Then, for the parameters of the fixed space-based optical detection system, the signal-to-clutter and availability were evaluated under different conditions. A linear relationship between the radiation intensity and the flight height of the target was obtained. For a space-based optical detection system, the analytical availability model was constructed. Fi-nally, multiple groups of data under different simulation conditions were used to validate the universality and reliabil-ity of the model. This availability model could significantly reduce the time required to predict the availability of the space-based optical detection system. The model was also adopted to analyze the influence of flight height, mean and variance, and background clutter on the space-based optical detection availability.