Tracking the surface figure error of the pick off mirror throughout build and environmental testing of the focus and alignment mechanism qualification unit of the near-infrared camera of JWST

The Pick Off Mirror (POM) is the business end of the Focus and Alignment Mechanism (FAM) of NIRCam. The POM harnesses the light delivered by the telescope and steers it into the Near Infrared Camera. At strategic points during the build and test of the Pick Off Mirror and its mechanism (the FAM) the surface figure error (SFE) of the mirror was monitored. This metric was used to track the health of the mirror throughout this testing regime. For example, the team ran an SFE test before and after Vibration testing the FAM. In this paper, we will provide an overview of the testing regime and the results of these periodic SFE tests. These results lead to the qualification of the POM and FAM designs for flight on the James Webb Space Telescope.