Structural analysis and testing of silicon x-ray mirror modules

Abstract

The fundamental developmental issue facing the next generation of X-ray astronomical telescopes is the manufacturability, assembly, and structural robustness of the grazing incidence optics. Combining the high angular resolution requirements with large effective areas and physical launch vehicle restrictions leads to very thin shelled optics that must remain very stable. Meeting these stability requirements while also surviving launch and space environments presents a significant engineering challenge. Over the last few years, the Next Generation X-ray Optics (NGXO) team at NASA Goddard has been developing thin segmented silicon optics that are assembled into both modules and meta-shells, which show great promise in meeting these challenges. This paper summarizes the analytical approaches, as well as the environmental tests, used to assess such assemblies. Many parameters in the design space of the assembly have been assessed and optimized using Finite Element (FE) models and ray trace algorithms. The results of these analyses have helped shape reasonable and justifiable error budgets, as well as guide the team’s decision making in both near and long term processes. The structural integrity of an assembly has been assessed both with testing and FE models. Preliminary strength testing has been conducted on the basic components used in the assembly.