Jan 4

Day 10: Sunshield Deployment Complete!

Webb Mission Operations Center (bottom right) and engineering room (top right) at Space Telescope Science Institute in Baltimore during the tensioning of the 5th sunshield layer (live-streamed by NASA).

What’s up with Webb Home

From an engineering perspective, Webb’s sunshield was one of the most difficult challenges to overcome in building the telescope. Unlike other parts of the telescope, the sunshield layers are very thin and easily damaged. How could the sunshield be safely and efficiently stored, and then deployed without tearing?

And, also unlike other parts of the telescope, almost everything to do with the sunshield had never been done in space before. Engineers not only had to figure out how to make the sunshield perform correctly and cool the telescope, but also how to test it on Earth so that it would deploy flawlessly in space.

Today, all of those thousands of hours designing and testing Webb’s sunshield paid off. The sunshield’s 5 layers were successfully tightened into their final positions. Sunshield deployment is complete!

Technically: there are 6 motors — one at each “corner” of the sunshield — and each motor drives all 5 layers at that corner. Each layer is deployed with 3 cables; 6 corners x 5 layers x 3 cables = 90 cables. They all functioned perfectly!

Four of the six sunshield corners are visible in this Webb image; two are hidden behind the telescope. Credit: NASA

If you could ask astronomers what’s been keeping them up at night, many would have said the sunshield deployment was high on the list. We are happy to report today that astronomers everywhere can sleep a little easier tonight.

Next up is the secondary mirror deployment.