Opto-mechanical design of long-strip space reflector applied to satellite perpendicular orbit scanning

Perpendicular orbit scanning is a novel satellite imaging mechanism proposed in recent years, which greatly enhances the efficiency of remote sensing imaging. However, its ultra-high-speed scanning requirements can only be fulfilled by using line-scan Charge Coupled Devices (CCDs) and long-strip space mirrors. So far, most common rectangular mirrors have a length-to-width ratio of no more than 3, employing a universal single-point or non-collinear three-point support design, with lack of further optimization exploration. Moreover, beyond static gravity and thermal loads, the mirror is required to maintain the surface shape and deformation during rotary scanning. Thus, balancing static and dynamic performance requires research and design. In this paper, we combine simulation calculations and topology optimization for the opto-mechanical design of a 360 × 60 mm planar mirror, using a dual-point flexible support with a spacing of 140 mm, which unlike the vast majority of published cases. After lightweighting, the mass of the whole mirror is less than 1.2 kg, the gravity surface deformation is less than λ/30 (λ = 632 nm), and the fundamental frequency is greater than 120 Hz. Under the unique 60°/s rotating imaging mechanism in the project, the surface deformation is 4.65 nm, and the displacement is less than 0.1 μm, which meets the engineering requirements. The design idea and the dynamic imaging working condition simulation in this paper can be used as a reference for other optical engineering.