Design of a non-vacuum focal plane presetting optical systems for space debris detection

To address the issues of system complexity and increased costs caused by vacuum focal plane pre-setting in space debris optical detection systems, this study proposes an innovative design method based on temperature-pressure coupling compensation. By precisely controlling the compensatory relationship between the defocus amount induced by operating temperature variations and that caused by the vacuum environment, the optimal focal plane position of the optical system under 20°C normal pressure automatically coincides with that under -10°C in-orbit vacuum conditions. The designed detection system based on this principle features a 50mm entrance pupil diameter, an F-number of 1.7, and a spectral range of 450nm to 850nm. Experimental results demonstrate that the focal plane position deviation between normal-pressure assembly and vacuum low-temperature operation is less than ±0.01mm. This system successfully eliminates the necessity of vacuum pre-setting in traditional designs while maintaining equivalent detection accuracy, significantly reducing system complexity and manufacturing costs. It provides a feasible technical pathway for the large-scale deployment of space debris monitoring equipment.