5 Parasols Are Better Than One
The Webb telescope will be oriented so that the Sun, Earth and Moon are always on one side of it, allowing the sunshield to act as a parasol, NASA says. The complete sunshield consists of five thin reflective layers of plastic that bounce heat back into space--and any energy they do absorb radiates out between the layers. Each layer is cooler than the one below it, overall conducting less heat than a single thick layer would.
Image: Northrop Grumman