In major milestone, NASA's Webb space telescope fully deploys its critical sunshield

The James Webb Space Telescope, now more than 570,000 miles outbound from Earth, successfully finished tightening all five layers of its sunshield Tuesday, completing one of the most complex — and risky — steps in the $10 billion observatory's initial activation.

Using six motors connected to 90 stainless steel cables running through scores of pulleys, the fifth and final hair-thin layer making up the 70-foot-long, 54-foot-wide sunshade was pulled into place and snugly tightened just before noon EST, giving Webb its iconic multi-layer kite-like appearance.

"I can confirm the final latch signature, which indicates that all five layers of the sunshield are fully tensioned," an unidentified engineer reported to the mission operations team at the Space Telescope Science Institute.