Fig. 1. Calculation flow of sensitivity analysis of PCE combined with Sobol' indices

Fig. 2. Calculation model of the whole chain of infrared radiation from rocket motor exhaust plumes

Fig. 3. Schematic diagram of LOS algorithm for radiative transfer equation solver

Fig. 4. Flow field and radiation signature of Atlas IIA plume at 21 km altitude. (a) Flow field; (b) comparison of calculated and reference values of the spectral radiant intensity

Fig. 5. Sample distribution of liquid oxygen kerosene rocket motor prototype parameters. (a) Oxygen-fuel ratio and combustion chamber pressure; (b) nozzle expansion ratio and nozzle diameter

Fig. 6. Sensitivity analysis of nozzle surface parameters of RD-180 rocket motor. (a) Main Sobol' indices; (b) total Sobol' indices

Fig. 7. Flight velocity corridor. (a) Velocity corridor consisting of 8 rocket flight trajectories; (b) velocity corridor of AtlasIII rocket

Fig. 8. Sensitivity analysis of spectral radiation intensity of RD-180 engine plume in 1‒20 μm band range. (a) 11 km; (b) 21 km; (c) 31 km; (d) 41 km; (e) 51 km; (f) 61 km

Fig. 9. Sensitivity analysis of RD-180 engine jet flame radiation intensity radiance. (a) 2.7‒3.0 μm band; (b) 4.2‒4.5 μm band;

Fig. 10. Variation of atmospheric pressure and difference in flight velocity corridor with altitude

Fig. 11. Input parameter coupling strength. (a) 2.7‒3.0 μm band; (b) 4.2‒4.5 μm band; (c) 3.7‒4.8 μm band; (d) 7.7‒9.5 μm band