Cryogenic bonding for lens mounts

Lockheed Martin Space Systems Company (LMSSC) has performed a feasibility study for bonded cryogenic optical mounts. That investigation represents a combined effort of design, experiments and analysis with the goal to develop and validate a working cryogenic mount system for refractive lens elements. The mount design incorporates thermal expansion matched bond pads and radial flexures to reduce bondline stress and induced optical distortion. Test coupons were constructed from lens and selected mount materials and bonded with candidate adhesives to simulate the design's bond pads. Thermal cycling of those coupons to 35K demonstrated both the system's survivability and the bond's structural integrity. Finally, a companion finite element study determined the bonded system's sensitivity to bondline thickness, adhesive modulus and adhesive CTE. The design team used those results to tailor the bondline parameters to minimize stress transmitted into the optic.