Assembly integration and ambient testing of the James Webb Space Telescope primary mirror

NASA’s James Webb Space Telescope (JWST) is a 6.6 m all-reflective on-axis three-mirror anastigmat. The 18-segment and fully actuated primary mirror (PM) presents unique and challenging assembly, integration and alignment requirements. In order to properly integrate the Primary Mirror Segment Assemblies (PMSAs) and align the completed PM, a variety of ground support equipment is used within a tower specifically built for the program. Handling fixtures, gravity offloaders, a variety of optical references, laser scanners, and interferometers are used. This paper outlines the hardware and techniques for integration and alignment of the JWST PM.