AOPP Seminar - An introduction to 3D printing lightweight mirrors for space-based telescopes

Abstract: Why 3D print lightweight mirrors: what are the benefits for space-based imaging and what is the state-of-the-art today? 3D printing creates objects layer-by-layer, and the primary benefit is in the increased design freedom enabling lattices and organic structures optimised for an application, rather than machining tool access. The secondary benefits include material homogeneity when combining a mirror with a mounting structure, and reduced time, cost and waste in downstream manufacturing processes. Space-based imaging well placed to harness these benefits due to its bespoke nature which rarely allows for off-the-shelf optical components. 3D printing replaces the machining/casting of a mirror substrate from a bulk material with a printed substrate, which can then be post-processed (single point diamond turned and/or polished) into an optical component. I’ll introduce the state-of-the-art in three materials (aluminium, silicon carbide and fused silica) and place my own research within this growing field. I’ll present my search for cleanliness in 3D printing of aluminium, highlighting how good process control creates printed mirrors comparable to conventional mirrors machined from RSA 6061; and I’ll discuss the opportunity of printed fused silica, where we have demonstrated sub-nm surface roughness and lightweight geometries tailored for X-ray reflection, thereby envisioning a successor to the Chandra X-ray Observatory.