Light Weight, Replicated Optics

Light Weight, Replicated Optics

Schafer has been a leader on innovative subsystem development, integration, and testing for a number of components with applications in missile defense, space and satellite operations, and lunar systems. Schafer's work in lightweight systems, specifically electroformed, replicated nickel optics, represents a significant technology improvement for these systems and provides suitable performance with lightweight systems that are very affordable compared to traditional materials and processing approaches.

Lightweight, all-reflective telescopes made from athermal thin shells of uniform nickel alloys provide a highly integrated structure that requires fewer connections, resulting in increased structural efficiency and lower alignment costs. The high fidelity optical alignment, surface finish, and surface figure of the replicated optics are built into the mandrels during the diamond turning process. The electroformed materials deposited over the mandrels have exceptional yield strength and good microyield behavior to provide mechanical stability, very good surface hardness to faithfully reproduce the surface figure with low scatter, and an acceptable coefficient of thermal expansion to be stable across a wide range of operating temperatures. The resulting optical surfaces can be conventionally coated to optimize performance from visible through thermal infrared wavebands.

The highly integrated nature of the optical and mechanical designs has been verified through vibration, shock, and thermal testing. Test articles and telescopes have been subjected to representational launch and flight loads to verify survivability and operational integrity. Acceptable athermal optical performance has been verified through measurement in a vacuum chamber and in an environmental chamber.

Replication processes for fabrication of multiple identical telescopes are more affordable than conventional approaches because the technical difficulty and cost is invested once in the manufacture of tooling and mandrels rather than repeatedly in the fabrication of every telescope. Therefore, cost savings rapidly accumulate when several of the same telescopes are needed for multiple interceptors for missile defense and constellations of satellite sensors and surface probes for NASA's space science and planetary exploration.