In order to resolve the large fluctuations in temperature range problem of Luojia 1-01 satellite caused by low heat inertia and poor thermal conductivity of structure, a quasi-all-passive thermal control system (TCS) design is presented under the conditions of limited resources including mass and power consumption. The effectiveness of the TCS design is verified by both ground thermal balanced test and related telemetry data of on-orbit performance. Firstly, according to the structural features and working modes of the satellite, isothermal design was implemented and the effectiveness was verified by thermal analysis using finite element method. Secondly, based on the results of the thermal analysis, thermal design was optimized and verified by the thermal balanced test. Finally, the thermal design was proved to be effective by temperature data acquired from telemetry data of on-orbit performance, and the thermal analysis model was improved and updated based on the results of thermal balanced test and temperature data of on-orbit performance. The on-orbit data indicates that temperature of optical camera stables at about 12 °C, temperature of battery stables at 19 °C, temperature of instruments inside and outside the satellite cabin is ranging from 10 °C to 25 °C. Temperature fluctuation range of optical camera is less than 2 °C when it is not imaging. Temperature fluctuation range of instruments not facing the sun is less than 4 °C. The data suggests that the temperature level of the satellite meets general design requirements, and the quasi-all-passive TCS design of the satellite is practicable.

The stray-light suppression of a large off-axis three-mirror anastigmatic space camera has been a hot topic, and this study proposes a composite stray-light suppression strategy that effectively suppresses stray light using the combination of a baffle, retaining ring, and internal antistray light measures. Additionally, the light barrier of the third mirror with a three-layered structure was designed to further optimize the composite stray-light suppression system. At the stray-light simulation analysis stage, in view of the limitations of the Torrance–Sparrow scattering analysis model, an analysis model with wide adaptability is proposed, which can be applied to the stray-light simulation analysis of large-size mirrors with rough surfaces. The simulation results indicate that the point source transmittance of the composite stray-light suppression strategy proposed in this paper is of the order of 10⁻⁵ before installing the light barrier of the third mirror, and the veiling glare index of the full field of view is less than 5.8%. After installing the light barrier of the third mirror, the point source transmittance reached the order of 10⁻⁸, and the veiling glare index of the full field of view was less than 1.31%. Moreover, the influence of the light barrier of the third mirror on the modulation transfer function of the system was less than 2.3%. The modulation transfer function test of the large-width off-axis three-mirror anastigmatic space camera in a simulated vacuum on-orbit environment was completed, and the test results indicated that the negative impact of the light barrier of the third mirror on the modulation transfer function was less than 3.6%. Moreover, an out-of-field imaging test of the space camera was conducted and the results showed that the image was clear, and the SNR reached 80 dB. The simulation and experimental results prove that the solution in this study can effectively solve the problem of stray-light suppression for large off-axis three-mirror anastigmatic space cameras.

The image quality of the large-scale, long-focus, large field of view, off-axis three-mirror anastigmat space telescope will decrease dramatically due to the thermal effect. This paper studies the thermal deformation of the telescope, and based on its axial deformation, it proposes a passive thermal compensation design using truss rods made of carbon fiber-reinforced plastics, utilizing its thermal conducting design, which is determined by different spread quantity and spread angle of the lamination. Meanwhile, it satisfies the system stiffness requirement. First, the truss rods are divided into several independent triangles, according to the principle of equal axial distance after deformation, the function in terms of coefficient of thermal expansion (CTE) and length of truss rods is determined. Bonded by the optical tolerance requirement, the range of the CTE is obtained. Second, according to the CTE function, coupled with the stiffness requirement of the whole instrument, the CTE of each truss rod is determined. According to the CTE and stiffness requirement, the design of truss rods lamination is carried out. Finally, the group of truss rods with unequal CTE is obtained. The results have been validated by finite element analysis, vibration experiments, and image test, which indicate that the accuracy of the space telescope studied meets the requirements of optical tolerance; in addition, the rotation angle of the front panel around the X axis is competent, implying the stiffness requirement is solved. Moreover, the modulation transfer function at Nyquist frequency is better than 0.178 under the condition of 20 ° C ± 5 ° C.

Optical Engineering (OE) publishes peer-reviewed papers reporting on research, development, and applications of optics, photonics, and imaging science and engineering.