NASA's James Webb Space Telescope has successfully deployed its 70-foot sunshield

It's an important milestone for the spacecraft.


The James Webb Space Telescope has completed one of the most challenging tasks involved in its mission to probe the depths of our universe. This week, NASA successfully deployed JWST’s 70-foot sunshield. The system is essential to the telescope’s operation. It will ensure its instruments don’t get colder than minus 380 degrees Fahrenheit so that they’re cold enough to see the infrared light that Webb is designed to track.

NASA began deployment of the sunshield three days after the telescope’s successful December 25th launch. The entire unfolding process took the better part of eight days, with a single day pause for the agency to optimize Webb’s power systems and tensioning motors. When you consider all the components involved, it’s easy to see why NASA says the process was so challenging. In all, unfolding and tensioning the sunshield involved 139 release mechanisms, 70 hinge assemblies, eight motors, about 400 pulleys and approximately a quarter-mile of cabling. If any one of those components failed, they could have set the entire project back.

At best, it would have been another delay in a long line of setbacks. Following a redesign in 2005, NASA declared the JWST ready in 2016, but manufacturing complications delayed assembly to 2019. The coronavirus pandemic then led to further delays in shipping and testing the telescope. There’s still more work to be done before scientists can use Webb to study black holes and other celestial bodies. Over the next five and a half months, NASA has to deploy the telescope’s secondary mirror as well as align its optics. After all that, the world will get a chance to see the first images it takes.