Ultra-Lightweight Optical Quality Deployable Mirrors

Objective is to develop and demonstrate ultra-lightweight, deployable, optical quality Carbon Shell Mirrors (CSMs), leading to high-quality, low-cost space telescopes. Will enable low cost, replicated mirrors and mirror segments, with ultra-low mass areal density, with individual mirrors scaling to meter size. In support of the objective of ultra-lightweight, low-cost segmented space telescopes, a compact high dynamic range primary mirror co-phasing technique was also developed.  Sample cube-sat mission was designed and 3D printed.

1) This research will demonstrate mirrors with a diameter of up to 40 cm, with post-control wavefront error less than 100 nm, and surface microroughness less than 5 nm. It will demonstrate Wavefront Sensing and Control (WFSC) dynamic range adequate to capture post-deployment figure errors up to 1 mm, with ultimate WFS&C error of 10 nm. The goal for the deployable mirrors volume prior to deployment is an envelope of 10 cm x 10 cm x 20 cm; an example cone-fold packaging scheme is shown in Fig. 1. The goal for the mass areal density of the mirrors is < 1 kg/m². The goal for the actuator areal density is >5,000/m².   2) The state of the art in lightweight space optics is the Actuated Hybrid Mirror (AHM) jointly developed by JPL/LLNL/Xinetics, which exhibits better performance than the goals listed above but with significantly greater areal density and without the ability to be folded or rolled for deployment. More conventional glass optics are even heavier, and lack correctability. Commercial deformable mirrors are available from multiple vendors, but are generally flat, heavy, not deployable, and not free-standing. The state of the art for high dynamic-range wavefront sensing is the reverse-Hartmann methods developed and demonstrated at U. of Arizona for fabrication of large (4m+) glass mirrors.