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Webb telescope team about to face crucial mirror deployment

NASA confirmed on Wednesday that the secondary mirror on the James Webb Space Telescope has been successfully deployed.

It means the team can now focus on one of the most crucial steps in the telescope’s deployment process — the opening up of the observatory’s mirror, which at 21.4 feet across is the largest such device ever sent to space.

The mirror is crucial to the mission’s success as it will be used to pick up light from distant galaxies and hopefully enable scientists to take our understanding of the universe to a whole new level.

✅ Secondary mirror deployed! But there's little time to pause and reflect.

Teams will ensure @NASAWebb's tripod structure is latched before beginning its final major milestone this week: full deployment of the space telescope's honeycomb-shaped primary mirror. pic.twitter.com/dT9kv5oDqS

— NASA Webb Telescope (@NASAWebb) January 5, 2022

Like the observatory’s sunshield, the mirror is so large that it had to be folded into a compact shape to fit inside the Ariane 5’s rocket fairing for the December 25 launch.

The sunshield has already successfully unfurled, while the deployment of the primary mirror is set to begin on Friday in a process that will likely finish the following day.

The procedure involves motors pushing into place a left wing and a right wing, each one holding three of the mirror’s 18 segments.

Once fully aligned, the wings will latch onto the main part of the mirror to keep them firmly in place.

A diagram of the James Webb Space Telescope.
NASA

NASA said the Webb mission needed a huge mirror to allow scientists to peer back through time to when galaxies were in their infancy.

“Webb will do this by observing galaxies that are very distant, at over 13 billion light-years away from us,” the space agency explains on its website. “To see such far-off and faint objects, Webb needs a large mirror. A telescope’s sensitivity, or how much detail it can see, is directly related to the size of the mirror area that collects light from the objects being observed. A larger area collects more light, just like a larger bucket collects more water in a rain shower than a small one.”

The James Webb Space Telescope is currently about 70% of the way to its destination orbit about a million miles from Earth.

Assuming the primary mirror deployment proceeds without a hitch, the $10 billion observatory will begin exploring the universe and beaming back data around the middle of this year.

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