NASA’s Webb windshield is successfully deployed and tensions in the final tests

Extended to the size of a tennis court, the five-layer windshield of the fully assembled James Webb space telescope assembled by NASA has successfully completed a final series of large-scale deployment and tension tests. This stage puts the observer one step closer to its launch in 2021.

“This is one of Webb’s greatest achievements in 2020,” said Alphonso Stewart, leader in Webb deployment systems for NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “We were able to accurately synchronize the movement in a very slow and controlled way and maintain its critical kite-like shape, which means it is ready to perform these actions in space.”

The windshield protects the telescope and reflects light and background heat from the Sun, Earth and Moon into space. The observatory must be kept cool to achieve innovative science in infrared light, which is invisible to human eyes and felt as heat.

In the shadow of the windshield, Webb’s innovative technologies and sensitive infrared sensors will allow scientists to observe distant galaxies and study many other interesting objects in the universe.

Maintaining the shape of the windshield involves a delicate and complicated process.

“Congratulations to the entire team. Due to Webb’s large size and strict performance requirements, the implementations are incredibly complex. In addition to the technical expertise required, this set of tests required detailed planning, determination, patience and open communication. The team demonstrated that it has all these attributes. It’s amazing to think that the next time Webb’s windshield is installed, it will be thousands of miles away, traversing space, “said James Cooper, Webb’s windshield manager at Goddard.

The Kapton polymer-coated membranes of the Webb windshield were fully deployed and tensioned in December at Northrop Grumman in Redondo Beach, California. Northrop Grumman designed the observatory’s parasol for NASA.

During testing, engineers sent a series of commands to the spacecraft’s hardware that activated 139 actuators, eight engines and thousands of other components to deploy and stretch the five windshield membranes into its final shape. A difficult part of the test is the deployment of the windshield in the Earth’s gravitational environment, which causes friction, unlike the material deployed in space without the effects of gravity.

For launch, the windshield will be folded around the two sides of the observatory and placed in an Ariane 5 launch vehicle, which is provided by the European Space Agency.

In this test, two pallet structures that hold the windshield in a vertical position folded, then two huge “arms” (known as the Mid-Boom assembly) of the windshield were telescoped slowly outwards, pulling the folded membranes together to resemble with synchronized movements a very slowly choreographed dance. Once the arms were locked in their horizontal position, the windshield membranes were successfully tensioned individually starting with the lower layer, separating each in their full form.

The large windshield divides the observer into a warm, sun-oriented part (about 185 degrees Fahrenheit) and a cold-oriented part (minus 388 degrees Fahrenheit), consisting of optics and scientific instruments. The windshield will protect the optics and sensors of the observer, so that it remains at extremely cold temperatures to drive science.

“This stage signals that Webb is about to be ready for launch. Our engineers and technicians have made incredible testing progress this month, significantly reducing the risk to the project by completing these stages for launch next year,” said Bill Ochs. project manager for Webb at Goddard. “The team is now preparing for the final testing of post-medium deployment on the observatory in the next few months before delivery to the launch site next summer.”

Webb passed other rigorous tests during its development, which successfully discovered and solved technical problems with the spacecraft. These tests confirm that once in orbit, the observer and its many redundant systems will work perfectly.