Improving optical and structural performances through adhesion angle optimization of curved secondary mirror holders for small satellites

This study investigates the optimization of adhesion angles in curved secondary mirror holders to enhance the optical and structural performance of small satellite optical payloads. A Cassegrain type optical telescope system was designed and analyzed to overcome small satellite constraints, such as limited payload volume, weight, and launch conditions. The payload is in 12U standards. The primary mirror diameter is 190 mm, the primary focal length is 300 mm, the effective focal length is 1000 mm and the focal ratio is f/5.26316. A CCD with high quantum efficiency and a pixel size of 5.6 (Formula presented) 5.6 (Formula presented) m was chosen as the detector. The study emphasizes the role of adhesion angles in balancing image quality and structural stability. Optical analyses, using metrics such as the Point Spread Function (PSF), Modulation Transfer Function (MTF), Fractional Encircled Energy (FEE), and Fourier transform patterns, demonstrated significant improvements in image quality with optimized curved holders. Among the configurations tested, a (Formula presented) adhesion angle (Model C) emerged as optimal, achieving high MTF and FEE values, while eliminating diffraction spikes and ensuring homogeneous light distribution across the detector. Model C achieved an MTF of 0.259, FEE of 94.89 %, and a PSF demonstrating homogeneous light distribution without diffraction spikes. Structural analyses validated its robustness, with natural frequencies exceeding 100 Hz and a safety factor above 3 under launch loads. Additionally, manufacturing errors were analyzed. The optimized (Formula presented) adhesion angle design balances optical performance with structural reliability, offering a compact and high performance solution for small satellite missions. This work provides valuable insights into the systematic design of secondary mirror holders, contributing to advancements in small satellite imaging capabilities for remote sensing and deep space observation applications.