Webb’s 5-Layer Sunshield

The sunshield on NASA's James Webb Space Telescope is the largest part of the observatory—five layers of thin membrane that was designed to unfurl reliably in space to precise tolerances. In 2014, engineers stacked and unfurled a full-sized test unit of the sunshield for the first time at a cleanroom in the Northrop Grumman Aerospace Systems facility in Redondo Beach, CA. The sunshield is about the length of a tennis court, and was folded up like an umbrella around the Webb telescope’s mirrors and instruments during launch. Once it reaches its orbit, the Webb telescope will receive a command from Earth to unfold, and separate the sunshield's five layers into their precisely stacked arrangement with its kite-like shape. The sunshield separates the observatory into a hot, sun-facing side (reaching temperatures close to 230 degrees Fahrenheit), and a cold side (approximately minus 400 degrees Fahrenheit) where the sunlight is blocked from interfering with the sensitive telescope instruments.