Increasing Structural Performance of Space Telescope Mirrors through Simultaneous Shape and Size Optimization

Abstract

In this paper, a numeric optimization approach for designing space telescope mirrors will be presented. It is fundamental to space telescopes that each element—including their mirrors—are as lightweight as possible. Moreover, the performance of space telescopes is driven by how strongly these mirrors are distorted upon removal of gravitational load. These distortions result in a deterioration in the optical performance, which is also known as the wavefront error. This error can best be described via Zernike polynomials. To increase the optical performance, along with making the mirror lightweight, the overall root mean square (RMS) of the deformation is used as the optimization objective. An approach utilizing size and shape variables is used to define the feasible design space for the optimization. Lastly, general findings will be discussed, as well as numerical advantages of deploying structural optimization (e.g., robustness evaluation).