The mechanical stiffness of large light weight mirrors is crucial to optical performance. Hextek substrates offer a superior stiffness to weight-ratio, when compared to other concepts due to our closed back sandwich structures. Hextek structured blanks have been examined using detailed finite element analysis (FEA) and lab testing. Not only have our mirrors proven themselves for terrestrial use but also air and space environments.
Some examples of 16-inch diameter mirror deflection appear below. An FEA analysis was done considering a mirror supported with a center hub type design. This is not the optimal design for a Hextek mirror; ideally a waffle-tree is optimal. The results illustrate the stiffness of a Hextek mirror is comparable to other light weight methods with the addition of even less mass. When the substrate diameter exceeds 24 inches, Gas-Fusion structured blanks continue to outperform the competition.
Hextek mirrors have been evaluated and used for mobile land, air and space-based applications. Our mirrors have been used in truck based LIDAR systems by Sandia National Labs and have flown in various aircraft including in the exposed belly of a PC-3 Orion for NASA. Hextek blanks have been successfully evaluated at Wallops Island and used in sounding rocket payloads multiple times for science missions that saw loads in excess of ±15 G’s. In addition, Hextek optics have been launched via a Pegasus launch vehicle and used in earth orbit in both the visible and IR. A 1.5 meter blank passed a vibration launch load chamber test to 20 G’s. Hextek substrates combine robust and light weight qualities for demanding applications.