Future space missions, such as SPICA and DARWIN, require large, light-weighted, and stiff mirrors with excellent
stability. During the past years, ECM fabricated a number of light-weighted mirrors. However, future large missions
require further advances with light-weighting, pushing this technology to the limit possible with recently developed
composite materials, new fabrication processes, and innovative designs.
In 2009, ECM took steps in this direction by fabricating successfully an ultra-lightweighted HB-Cesic® mirror
demonstrator 1 m in size. We demonstrated that HB-Cesic®, due to its extreme light-weighting capability and
manufacturing versatility, combined with high stiffness, high mechanical strength, and low CTE at cryogenic
temperatures, is able to fully meet the requirements of future large cryogenic space mirrors.
In this paper we describe the fabrication process of this demonstrator and its physical characteristics.