KEYWORDS: Staring arrays, Cameras, Flexible circuits, Copper, Resistance, Heatsinks, Control systems, Energy efficiency, Power supplies, Monte Carlo methods
The structure of a space electric cabinet based on a commercial CMOS chip is presented. Analysis is conducted according to the temperature specifications and the environmental constraints, which indicates the partitional thermal control method has higher energy efficiency than conventional TEC cooling. A flexible graphite thermal cable is used to build an independent cooling path for the focal plane component. The camera hood is utilized to cool down the peripheral circuit. Copper sinks are designed for high power electronic components. The thermal control design is verified by finite element simulation analysis and thermal balance test. The experimental results show that the partitional thermal control measures are effective and feasible, which can ensure the -30°C operating temperature of CMOS chip and the derating requirements of components with high power consumption.
The sources of different spurious radiation in infrared optical system are analyzed, and the measures to suppress the spurious radiation are listed. Taking the infrared optical system of a detector as an example, the stray radiation of the infrared optical system is suppressed by setting the lyot stop. The optical and mechanical structure model of the infrared optical system was established, and the Monte Carlo method in LightTools software was used for ray tracing analysis. The illuminance of the image plane of the detector after adding lyot stop was obtained, and the point source transmittance (PST) and veiling glare index (V) of the infrared system were calculated, and the effectiveness of the suppression effect was evaluated. At the same time, the background heat radiation of the internal optical and mechanical structure of the infrared optical system is simulated and analyzed. The comprehensive consideration ensures that the imaging quality of the infrared optical system is not affected.
In order to improve the imaging quality of the space target detection camera while minimizing the size of the camera structure and facilitating its attitude control, a retractable lens hood is proposed. The basic structure and design method of the telescopic lens hood are introduced. The use of a retractable lens hood structure to replace the long lens hood in the previous design, optimizes the structure of the system, and greatly reduces the size of the system. Analyze the feasibility of the camera's retractable lens hood and the suppression effect of stray light. Use LightTools software to build a model to analyze the ray tracing of the camera's hood. The results show that the point source transmittance (PST) of the retractable hood is gradually reduced under different off-axis angles. When the off-axis angle is greater than 30°, the PST of the optical system reaches the order of 10-6 , which effectively suppresses the stray light of the system.
The image quality of reflective optical systems is influenced strongly when the position of each mirror changed compared to the theoretical design state. Since multiple degrees of freedom in reflective optical system and the interaction between each mirror coupled, which makes it difficult to separate the misalignment of each mirror accurately. By now, vector wave-front aberration theory has been used to computer-aided alignment of two-mirror and three-mirror optical systems widely, however, due to actual engineering demands, optical systems with more than three mirrors have been designed, which greatly increases the difficulty of installation and alignment. At present, there are still few researches on this aspect. Based on vector wave aberration theory, the aberration shift vector of each element in four-mirror optical systems with off-axis field is derived by using paraxial ray trace equation of the optical axis ray and the principle ray, then the misalignment model of the four-mirror optical systems with shifted field is established in detail. The model can accurately calculate the misalignment of optical elements, which greatly promotes the high-precision alignment of complex reflective optical systems. And the perturbed off-axis four-mirror telescope can be perfectly aligned in terms of the vector aberration theory. This greatly facilitates the optical design technology of complex reflective optical systems in some way.
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