Design and thermal characteristic test of a temperature control system for spacecraft precision instrument

The temperature control precision is crucial for the sensitive elements in a spacecraft. In the present study, a temperature control system to improve the performance of spacecraft precision instruments was designed and experimentally investigated. In the temperature control system, heat pipes, high emissivity coatings, and semiconductor coolers are applied to dissipate the internal heat and control the temperature of a sensitive element. Heat pipes are arranged on the sensitive element and the innermost shell, high radiation coatings are sprayed on each shell surface to transfer the heat to the outer layer, and semiconductor coolers are mounted on the outermost shell and dissipate heat to the external environment. The temperature of the sensitive element is compensated by an electric heating device to reduce the temperature fluctuations. A digital-analog control scheme was designed to maintain the temperature of the outer shell and the sensitive component of the temperature control system. The control accuracy of the temperature control system is within ±0.1 ℃ under different working conditions. When the frequency point is at 0.089928 Hz, the signal amplitude of temperature is taken as the maximum value of 5.05 mK; the amplitude spectral density is 0.006 ∼ 9 mK/Hz1/2 in the frequency range 0.001 ∼ 0.25 Hz.