Research on heat flow avoidance and shielding methods for light inlet of space infrared cryogenic optical remote sensor

Abstract To improve the accuracy and sensitivity of remote sensors, cryogenic optical technology has been widely developed in recent years. To achieve a low temperature of the optical-mechanical system of the remote sensor, necessary refrigeration schemes are required, with both radiation cooling and mechanical cooling requiring substantial resources. To reduce the refrigeration cost, controlling the thermal load of the cryogenic optical-mechanical system is the focus of the thermal control design. The space heat flow at the light inlet is an ever-present thermal load in cryogenic optical systems, especially for low-orbit remote sensors, which are subject to complex changes in the heat flow in space. Reducing the heat flow absorbed at the light inlet is an important part of the thermal control design of cryogenic optics. This paper presents the thermal control of a large-aperture cryogenic optical remote sensor. Aiming at the low-altitude and high-inclination orbit and cryogenic control of the remote sensor, the regularity of the spatial heat flow in different directions of the remote sensor is analyzed. Based on the mobility capability of the two-dimensional turntable, a heat flow avoidance strategy for the remote sensor light inlet is provided. To further reduce the impact of the light inlet heat flow on the cryogenic optical system, a shield is used to block the heat flow at the light inlet. This minimizes the spatial thermal load at the light inlet of the large-aperture cryogenic optical system, the foundation for the cryogenic realization of the entire optical system.