So far, for the James Webb Space Telescope (JWST), everything’s cool — and getting cooler.
That’s because on Jan. 4, NASA’s newest flagship observatory successfully deployed its sunshield, a tennis court-sized parasol that will keep its mirrors and sensitive instruments permanently shaded from the Sun.
The deployment is a major milestone in the complex and risky procedure of bringing the telescope online. Since JWST launched Dec. 25 from French Guiana, the operations team at the Space Telescope Science Institute in Baltimore has been meticulously working to deploy each of the observatory’s parts and systems from the folded-up compact configuration that it launched in.
This complex series of procedures is full of potential pitfalls, but the sunshield, in particular, was one of the trickiest parts and is crucial to the entire design of the telescope.
It consists of five kite-shaped layers of an aluminum-coated film about 70 feet (21 meters) long and 54 feet (16 m) wide. As the name suggests, it blocks the heat of the Sun (as well as Earth), allowing the telescope to cool to –370 degrees Fahrenheit (–223 degrees Celsius). But it also acts as a radiator, dissipating heat from JWST’s computers and other support systems and stopping it from bleeding to its instruments. Both functions are necessary for the telescope to observe at the infrared wavelengths that will allow it to peer back in time across the universe to some of the earliest galaxies.
Flexible timeline
To deploy the sunshield in space, NASA first unfolded the sunshield’s fore and aft support structures and raised the tower that the telescope itself sits on, creating room for the shield to unfold beneath it. Then, late on New Year’s Eve, the team extended the booms that stretched the shield to its full width. Finally, each individual layer had to be pulled taut, or tensioned, around their frames. In all, the process involved 139 release mechanisms, 70 hinge assemblies, eight motors, 90 cables, and about 400 pulleys.
NASA took a deliberate approach to the tensioning, delaying the process a couple days after two concerns arose — both related to the telescope’s thermal characteristics. First, the array of solar panels was providing less power to the telescope than expected. And second, the sunshield deployment motors were hotter than expected, though not hotter than their design limits.
James Webb Space Telescope successfully deploys sunshield
Source: Trending Update Article
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