Mirror actively deformed and regulated for applications in space: design and performance

TL;DR

This paper presents a space-compatible active deformable mirror system with high precision correction capabilities, demonstrating its potential for future lightweight space telescopes and achieving a technology readiness level of 4.

Contribution

Development and testing of a 24-actuator active mirror system tailored for space telescopes, demonstrating effective wavefront correction for lightweight primary mirrors.

Findings

Achieved correction precision better than 10 nm rms.

Successfully demonstrated mirror performance in a dedicated testbed.

Technology maturity increased to TRL4.

Abstract

The need for both high quality images and lightweight structures is one of the main drivers in space telescope design. An efficient wavefront control system will become mandatory in future large observatories, retaining performance while relaxing specifications in the global system's stability. We present the mirror actively deformed and regulated for applications in space project, which aims to demonstrate the applicability of active optics for future space instrumentation. It has led to the development of a 24-actuator, 90-mm-diameter active mirror, able to compensate for large lightweight primary mirror deformations in the telescope's exit pupil. The correcting system has been designed for expected wavefront errors from 3-m-class lightweight primary mirrors, while also taking into account constraints for space use. Finite element analysis allowed an optimization of the system in order to achieve a precision of correction better than 10 nm rms. A dedicated testbed has been designed to fully characterize the integrated system performance in representative operating conditions. It is composed of: a telescope simulator, an active correction loop, a point spread function imager, and a Fizeau interferometer. All conducted tests demonstrated the correcting mirror performance and has improved this technology maturity to a TRL4.