NASA's James Webb Space Telescope deploys sunshield, evades many ‘single-point failures'

The National Aeronautics and Space Administration on Wednesday was thrilled to announce that its new James Webb telescope has achieved a major milestone after the complete deployment of the space observatory's giant 70-foot kite-shaped sunshield with tennis court-sized barrier. In a  web blog, NASA informed that it was able to achieve the deployment after the sunshield tensioning and secondary mirror deployment was completed on the 10th day after launch. James Webb’s unfolding and tensioning of the sunshield involved 139 of Webb’s 178 release mechanisms, 70 hinge assemblies, eight deployment motors, roughly 400 pulleys, and 90 individual cables totalling roughly one-quarter of a mile in length, according to the space administration.  

Meanwhile, NASA's ohn Durning, the deputy project manager for the Webb mission, told The Washington Post; “I am thrilled. I’ve been on the job 15 years. To see it unfurl in space, it’s awe-inspiring.”

As per NASA, James Web telescope’s sunshield was folded to fit inside the payload area of an Arianespace Ariane 5 rocket’s nose cone prior to launch. NASA’s Webb team began remotely deploying the sunshield on Dec. 28, 2021, three days after launch, and explained the process in a briefing at 12:45 p.m. EST, Jan. 4,  as the team waited for the critical step to finish. 

“Unfolding Webb’s sunshield in space is an incredible milestone, crucial to the success of the mission,” Gregory L. Robinson, Webb’s program director at NASA Headquarters said in NASA’s statement. 

“Thousands of parts had to work with precision for this marvel of engineering to fully unfurl. The team has accomplished an audacious feat with the complexity of this deployment – one of the boldest undertakings yet for Webb,” he added.

Sunshield 'protection is crucial': NASA

NASA’s James Webb telescope will find the initial cosmos during the early days of the universe’s formation from the Bing Bang. Moreover, the five-layered sunshield will protect the telescope from the light and heat of the Sun, Earth, and Moon during this mission. Sunshield’s plastic sheet which is as thin as human hair is coated with reflective metal and will provide protection on the order of more than SPF 1 million.

NASA engineers successfully completed the deployment of the James Webb Space Telescope’s sunshield, seen here during its final deployment test on Earth in December 2020 at Northrop Grumman in Redondo Beach, California. [Credit: NASA]

The five layers on the sunshield will reduce exposure for the telescope from the harsh rays of the sun, and from over 200 kilowatts of solar energy to a fraction of a watt. “This protection is crucial to keep Webb’s scientific instruments at temperatures of 40 kelvins, or under minus 380 degrees Fahrenheit – cold enough to see the faint infrared light that Webb seeks to observe,” NASA explained. 

As per NASA, the unfolding of the sunshield occurred in the following order, and finished over the course of eight days:

• Two pallet structures located in the forward and back began unfolded to bring the observatory to its full 70-foot length
• The Deployable Tower Assembly was assigned to separate the telescope and instruments from the sunshield. This component also separated the main body of the spacecraft in order to allow more room for the telescope’s sunshield to fully deploy
• The aft momentum flap and membrane covers were later released and deployed to pave way for further deployment processes
• The mid-booms deployed, expanding perpendicular to the pallet structures and allowing the sunshield to extend to its full width of 47 feet
• Finally, at approximately 11:59 a.m. EST Tuesday, the sunshield was fully tensioned and secured into position, marking the completion of the sunshield deployment.