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Webb space telescope has launched, but trickiest bit is yet to come

The James Webb Space Telescope launched to great fanfare on Christmas Day, with the powerful device promising great things during the course of its mission to explore deep space.

Many watching the livestream of Saturday’s launch were likely holding their breath during the countdown, though there was no need to worry. Arianespace’s trusty Ariane 5 rocket did the job, lifting the James Webb Space Telescope to space in a perfect start to the multiyear mission.

But for the Webb team — comprising personnel from NASA, the European Space Agency, and the Canadian Space Agency — the tension won’t recede until the telescope has fully deployed so that it can begin its work to explore the universe. And that deployment is far from straightforward.

The satellite’s enormous size meant that its myriad of components had to be folded into a compact shape so that it could fit inside the rocket’s fairing for launch.

Over the coming weeks, as the telescope travels through space, each of these components will automatically deploy via a highly complex sequence of maneuvers.

And if any one of these maneuvers goes wrong, it could well be curtains for the $10 billion project.

James Webb Space Telescope Deployment Sequence (Nominal)

The good news is that the initial deployments have gone to plan. They include the solar array, which released and deployed about 30 minutes after launch, and the gimbaled antenna assembly, which successfully deployed on December 26.

“Our team just deployed the gimbaled antenna assembly, which includes Webb’s high-data-rate dish antenna,” NASA said in a tweet. “This antenna will be used to send at least 28.6GB of data down from the observatory, twice a day.”

📞 Hello Webb? It's us, Earth!

Our team just deployed the gimbaled antenna assembly, which includes Webb’s high-data-rate dish antenna. This antenna will be used to send at least 28.6 Gbytes of data down from the observatory, twice a day: https://t.co/4vKcbjbKJO pic.twitter.com/zFjhF3yLzY

— NASA Webb Telescope (@NASAWebb) December 26, 2021

On Tuesday, December 28, one of the most challenging deployment stages will begin. It involves the enormous sunshield, described as the size of a tennis court and requiring a slew of motors to push it into position. It will take five days for the sunshield to fully unfurl, and no, we doubt the Webb team will be getting much sleep during this crucial process.

Assuming the sunshield successfully unfurls, Webb will then be in a position to deploy the secondary mirror and the instrument radiator in early January.

Thirteen days after launch comes another step that’s likely to give team members and Webb fans a few more sleepless nights — the deployment of the 21-foot-wide golden mirror that’s central to its mission.

The procedure involves the locking into place of two wings of mirrors, each one holding three of the entire mirror’s 18 segments. Successful completion of this stage will mark the telescope’s full deployment.

Webb will then spend a couple more weeks traveling to its destination orbit at a point known as L2, about four times the distance between Earth and the moon. Over the following five months the mirror’s alignment will be fine-tuned and the telescope’s instruments calibrated.

And then the fun begins.

For more details on the various deployment stages, check out NASA’s special site for the James Webb Space Telescope mission.

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Trevor Mogg
Contributing Editor
Not so many moons ago, Trevor moved from one tea-loving island nation that drives on the left (Britain) to another (Japan)…
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