The Webb telescope's giant primary mirror, arguably its most critical and difficult part, is approaching completion. The 18-segment mirror stands two stories high and is designed to best capture the infrared light Webb seeks. Follow the mirror's journey from rough ore to precisely reflective, gold-coated segments in this video, which details how the mirrors are constructed and tested.
Produced by the Space Telescope Science Institute (STScI)
Publication: August 23, 2011