1/3rd scale shield
"The James Webb Space Telescope has a unique shield to protect its sensitive instruments from the heat and light of the sun. The sunshield is like an umbrella popping open on the shores of the cosmos that allows the instruments beneath it to see far into the universe.
Like a beach umbrella protects people from the sun's heat and ultraviolet radiation, the sunshield protects the telescope and the sensitive infrared instruments that fly beneath the Webb telescope's sunshield from our sun's heat and light. "Each of the five layers of the shield is less than half the thickness of a piece of paper. The five work together to create an effective SPF (or Sun Protection Factor) of 1,000,000," said John Durning, Deputy Project Manager for the James Webb Space Telescope Project, at NASA's Goddard Space Flight Center, Greenbelt, Md.
A new video takes viewers to Northrop Grumman's Astro Aerospace in Carpinteria, Calif. to understand the mechanics necessary to unfold the large tennis-court sized sunshield. In the 3:00 minute video, engineers are interviewed to explain how the new technology extends the sunshield in space and unfurls it before the Webb telescope attains orbit one million miles from Earth."
JWST @ NASA