A novel small perturbation analytical model to investigate temperature control characteristics of spacecraft thermal systems in frequency domain

• Novel analytical method for high precision temperature control of thermal systems. • Noise suppression characteristics of thermal control system in frequency domain. • Revealing frequency components and temperature power spectral density in signals. • Identifying key factors in the passive thermal design of satellite payloads. • Suppression of low-frequency complex noise by multichannel disturbance analysis. This paper introduces a small perturbation frequency domain thermal analysis model based on the nonlinear dynamics model. The model can be applied to study the high-precision temperature control of thermal systems under low-frequency complex perturbations. The frequency domain characteristics of the space gravitational wave detection satellite are analyzed, and a multi-channel perturbation structure is established. The effects of three kinds of heat flow perturbations, including external heat flow, power generation power, and waste heat of electronic equipment, on the temperature through five transfer paths are investigated. It has been discovered that the waste heat from electronic equipment inside the satellite has the most noticeable effect on the temperature power spectral density of temperature-sensitive optical loads, serving as the primary factor influencing thermal stability. For complex noise signals, the small perturbation analysis method can decompose the different frequency components or ranges, reducing the problem to linearized analysis and simplifying complex calculations. The results indicate that the temperature power spectral density decreases as signal frequency increases, with low-frequency signals exerting a greater influence on temperature stability. The small perturbation analysis method is a novel and effective method for temperature control of space thermal systems, with high accuracy and stability.