Wavefront correction using MEMS deformable mirror for Earth observation satellite with large segmented telescope

Abstract

A demand for responsive, high-resolution Earth observations is emerging for mitigating the human suffering and damage that follow large-scale disasters. One of the most promising advances is a sophisticated optical imager with a large, 3.6-m satellite-mounted telescope in geostationary orbit. The imager of the proposed space telescope has a segmented mirror and offers a ground sampling distance of better than 10 m and a latency of shorter than 30 minutes. For the imager to realize diffraction-limited performance, deformable mirrors are planned to be installed at the exit pupil of the telescope system. One candidate for the deformable mirrors in segmented telescope is based on a micro-electromechanical system (MEMS) that offers a small actuator pitch, fine step resolution, and excellent hysteretic motion response. This paper presents the wavefront correction of aberrations with a high and low spatial frequency using MEMS deformable mirror on an optical testbed. The expected image quality is also evaluated through numerical simulation.