Rules for optical metrology: Webb primary mirror case study

The Webb Space Telescope’s on-orbit performance was made possible by successful in-process optical testing and cryogenic requirement compliance certification, verification, and validation of the Webb optical components. This was accomplished by the hard work of dozens of optical metrologists, the development and qualification of multiple custom test setups, and several inventions, including 4D PhaseCam and Leica absolute distance meter. We define a set of rules for optical metrology and summarize how they were applied to the metrology tools, test setups, and processes used to characterize the Webb Space Telescope primary mirror segment assemblies.