Defocus range of off-axis three-mirror anastigmat (TMA) camera under space microgravity

Abstract

The mirror interval and radius of curvature of optical system including three mirrors are often changed due to the impact of space microgravity,which has a greater impact on the back focal length,and causes camera defocus and imaging quality reduction.Through the equivalent Gauss optical system analysis of three-mirror system,back focal length formula can be obtained.By homogeneous coordinate transformation,the reflection mirror rigid-body displacement formula is obtained,and a mirror radius is obtained in the microgravity environment using the least squares fitting algorithm.Finally,by calculating the camera in space microgravity environment,the defocusing amount is 0.04 mm.Results provide a theoretical basis for the design of focusing mechanism.