All-aluminum high-resolution camera with lightweight and compact size

In order to meet the urgent need of developing lightweight and compact space cameras quickly, effectively, and rapidly, a detailed comparative analysis is conducted, including optical system forms and imaging systems. The optical system form of RC+ compensation group is determined, and the imaging system of small F#+micropixel is adopted. Compared with the detailed parameters of the DOVE camera, a lightweight all-aluminum high-resolution camera with a resolution of 3.48 m at an orbital altitude of 500 km is designed. The overall design results of the camera, its optical and optomechanical structures, imaging electronics, and thermal control are described in detail. The optical design results of the RC+ compensation group of F5.6 are obtained. Using RSA-6061 microcrystalline aluminum alloy as the structural material of the mirror, coupled with an integrated high-rigidity hard aluminum alloy structure, the static (gravity and temperature deformation) simulation analysis results meet the optical design tolerance requirements. The dynamic simulation analysis results show that the first order mode is 302.92 Hz, which has a sufficiently high dynamic stiffness and safety redundancy. The imaging electronics using a 3.2 μm large area array 9 K×7 K detector is designed for low noise miniaturization. Thermal control is provided by the satellite platform at a temperature level of 20 °C± 4 °C for the camera. Integration test results show that: (1) The RMS wave aberration of the central field of view is λ/15.6, and the wavefront aberration of the five fields of view is better than λ/12.3, which ensure high-quality imaging near the diffraction limit of the camera. The measured optical transfer function at Nyquist frequency is 0.217; (2) The maximum sinusoidal vibration of the camera in three directions is amplified 1.17 times, and the first-order mode of the camera is 295 Hz, with a deviation of 2.61% from the simulation result. The structural stiffness is high and the mechanical stability is good. Under vacuum environment of 10⁻⁴ Pa and three different temperatures of 16 °C, 20 °C and 24 °C, the image is clear and can distinguish the corresponding resolution plate image at Nyquist frequency; (3) The image of 2 km outfield target is good, as well as clear and distinct grayscale image with sharp shadow boundaries. The all-aluminum high-resolution camera is achieved 3.48 m resolution at a track height of 500 km,width of 15 km×15 km and a total weight of 2 kg. The structural rigidity and strength test results meet the requirements of space launch scenarios, and these can provide theoretical guidance and engineering reference for the design of lightweight and higher-resolution space cameras.