Progress on high-resolution thin full monolithic shells made of glass for Lynx

The Lynx X-ray Observatory, with superb imaging capabilities and with large throughput, is one of the four large strategic missions considered in the Astro2020 decadal survey. The realization of the mirror assembly within the desired tolerances is quite challenging and different mirror module concepts are proposed. The simplest mirror module design corresponds to less than a few hundred monolithic shells made of fused silica. The complete optomechanical design, compliant with the mass budget, foresees that the shell thickness ranges between 2 and 4 mm (for mirror shells between 0.4 and 3 m diameter). A technology development roadmap for this approach is funded in Italy by ASI and pursued out by INAF-OAB. In this paper, we present the advancements obtained in the procurement of new raw glass shells, in the development of the different phases of the process, and in the realization of a new single-reflection shell, representative of the final optical configuration suitable to validate the