NASA James Webb Space Telescope Starts Most Complicated Challenge of Unfolding Its Sunshield

The James Webb Space Telescope, NASA's most powerful space telescope, has been in orbit for three days. However, the most dangerous aspect of its voyage to deep space is still to come. Soon, the telescope's fragile sun shield will be deployed in a meticulously planned mechanical dance.

It's a new kind of reverse space origami that's never been done before, but it's critical for the James Webb Space Telescope (JWST) to complete its mission. The telescope was too large to launch while fully extended on any working rocket. As a result, when it launched into orbit on Christmas Day atop a European Ariane 5 rocket, it was folded like the world's most costly Swiss Army knife.

James Webb Space Telescope Starts Unfolding Giant Sunshield

JWST will twist and contort over the following two weeks, deploying one beam here, a mirror there, until it is fully outfitted for looking into the darkest reaches of the Universe.

The Verge said that JWST's mirror flaps would be deployed 12 to 13 days following launch. However, before that can happen, the observatory must perform an even more complicated deployment, which might take up to six days - the deployment of JWST's sunshield, a complex device meant to keep the telescope cool while in space by blocking heat from the sun.

While the deployment procedure is meant to be flexible and things can change, the first part of the sunshield deployment is set to begin today, which means nearly everyone involved with the mission will be holding their breath for the next week.

NASA said the spacecraft took a crucial step in its deployment on Tuesday when it unfurled the Forward Unitized Pallet Structure (UPS) of its massive sunshield. According to the agency, the procedure took four hours and ended at 1:21 p.m. EST. According to an update from the agency, Webb then repeated the procedure with the Aft UPS, which completed deployment at 7:27 p.m. EST on Tuesday.

Taking the next step, NASA officials wrote that UPS involved hundreds of distinct processes. The successful maneuver is the first in a five-day procedure to prepare the sunshield, which will shield Webb's delicate equipment from the sun's rays.

"While the actual motion to lower the forward pallet from its stowed to its deployed position took only 20 minutes, and the lowering of the aft pallet took only 18 minutes, the overall process took several hours for each because of the dozens of additional steps required," NASA officials said in a statement. "These include closely monitoring structural temperatures, maneuvering the observatory with respect to the sun to provide optimal temperatures, turning on heaters to warm key components, activating release mechanisms, configuring electronics and software, and ultimately latching the pallets into place."

Although each stage of the deployment sequence is controlled from the ground, and the timing can be altered as NASA, and its partners see fit, the sunshield deployment procedure is expected to end around Jan. 3.

What's Next After JWST Unfolds Sunshield

Webb's next actions will be to unfold the Deployable Tower Assembly, release the sunshield cover, and begin unfurling the sunshield itself when the two UPS structures have been unfolded. The observatory will be in its final configuration in orbit within one month after launch if all goes according to plan.

Space.com said the spacecraft would orbit Earth-sun Lagrange point 2, or L2, about 1.5 million kilometers (930,000 miles) away on the opposite side of the sun. Like the fragile sun shield, this placement is critical for allowing the equipment to collect infrared observations.

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