JWST primary mirror material selection

The James Webb Space Telescope (JWST) conducted a phased down select for its primary mirror. Using the results of the Advanced Mirror System Demonstrator (AMSD) as a basis, the Mirror Recommendation Board (MRB) assessed the suitability for JWST of candidate mirrors in the areas of performance, schedule, cost and risk. Beryllium was selected for the JWST primary mirror. This paper summarizes the evaluation and selection process.