James Webb Space Telescope completes tricky sunshield deployment

The most nerve-wracking part of the telescope's deployment was the deployment of all five layers of the sun shield.

Today's procedure, which required careful tensioning of the five hair-thin layers of the sun shield structure, was a success. Thousands of engineers involved in the project over the past three decades of development were relieved when it was completed.
The observatory manager for the James Webb Space Telescope said in a live NASA webcast that they didn't think they would get through the first three layers. The team executed everything perfectly. We only planned to do one yesterday, but it went so well. Can we just keep going? We almost had to hold them back.
An astronomer explains how to send a giant telescope to space.

Today, a complex system of cables and motors pulled at the corners of the sun shield to secure the right tension for each layer.
The sun shield's diamond-shaped layers were tightened on Monday. The first day was when NASA expected each layer to take, but by the end of the day three layers were tensioned and the last two were tightened.
The deployment of the fourth layer was successful. The telescope was 546,000 miles from Earth. The fifth layer was tensioned at 12:14. Control teams gave a cheer and applause when it was over.
One of the operations managers could be heard saying in the webstream that he wanted to congratulate the entire team. Getting the sun shield deployed is really, really big and we still have a lot of work to do.

Even the most high-tech test lab can't fully mimic the effects of weightlessness and other factors present in outer space, even though the sun shield deployment was thoroughly tested on Earth. The mission cost $10 billion and took three decades to build, so it could have been in jeopardy if anything went wrong.
The sensitive detectors of the James Webb Space Telescope have to be extremely cold to work as they are designed.

It has to be kept at extremely cold temperatures so that it doesn't get warm and obscure its observations. The sun shield reflects both incoming solar radiation and heat from planet Earth.
The ultimate goal of the project is to detect the faint light coming from the most distant stars and galaxies, which lit up the dark universe in the first hundreds of millions of years after the Big Bang. The heat from the telescope would dazzle the detectors.
"We get about a 100 degree Fahrenheit (55 degrees Celsius) drop per layer," he said. The instrument detectors on the observatory are running at minus 400 degrees F, which is the lowest temperature on the observatory.

Against all obstacles.

As humans on Earth contend with a new surge of the COVID-19 virus brought about by the recently discovered Omicron variant, many team members were forced into isolation.
One of the challenges has been isolating people who have been working on this for a long time. They can help us remotely from wherever they are if we hook them up to our operations loop.

The James Webb Space Telescope is heading for a place called the Earth-sun Lagrange Point 2, which is some 1.5 million km away from the planet. L2 is one of five points between the sun and Earth where the interplay of the two bodies keeps an object in a stable position. The sun will be hidden from the star's rays by the James Webb Space Telescope.
The operations teams will move on to the telescope's secondary mirror after the sun shield is fully unfurled.
"We're going to get some heaters on to start heating up the motors that actually do the deployment of our secondary mirror system," said Parrish. We'll get that heated up and we'll move on.

The end of January is when the L2 will be reached. The primary mirror was folded for launch because of its large size, and will be fully deployed once the scope arrives.
The mirror's 18 gold-coated hexagonal segments will take 100 days to cool down. Astronomers can take pictures of the most distant universe if the seams between them are smooth. The first images from the telescope are expected in the summer of 2022.
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