James Webb Space Telescope’s golden mirror opened for final tests one last time before October launch
Tests planned to ensure that 18 hexagonal mirrors part of Webb are prepared for a long journey in space

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Your support makes all the difference.Nasa engineers have fully opened the iconic 6.5m wide solar mirror of the James Webb Space Telescope (JWST) one last time for final tests before its launch planned for later this year.
The giant mirror part of JWST – the world’s largest and most powerful space science telescope – was commanded to open fully just like it would deploy in space.
According to Nasa, the telescope – also called Webb – contains many movable parts that have been specifically designed to fold themselves like a piece of origami artwork into a compact formation that is considerably smaller than when it is fully deployed, allowing it to fit inside a 5m rocket with little spare room.
“The primary mirror is a technological marvel. The lightweight mirrors, coatings, actuators and mechanisms, electronics and thermal blankets when fully deployed form a single precise mirror that is truly remarkable,” Lee Feinberg, optical telescope element manager at NASA’s Goddard Space Flight Center in Maryland, said in a statement.
From the tests, the team plans to ensure that the 18 hexagonal mirrors part of the telescope are prepared for a long journey in space, and a life of discovery.
One of the tests assessed Webb’s deployment in its intended space environment using gravity offsetting equipment.
Such assessment, according to Nasa, would confirm that all the movable parts of the telescope, including 132 individual actuators and motors, work as intendend in their launch environment.
“This is not just the final deployment test sequence that the team has pulled off to prepare Webb for a life in space, but it means when we finish, that the primary mirror will be locked in place for launch,” Feinberg explained.
As part of the tests, software instructions were sent from Webb’s testing control room at Northrop Grumman, in Redondo Beach, California to unlatch and deploy the side panels of the mirror.
According to Nasa, these commands and mechanisms are the same as those that will be used to deploy the mirrors in space.
“Pioneering space observatories like Webb only come to fruition when dedicated individuals work together to surmount the challenge of building something that has never been done before,” said Ritva Keski-Kuha, deputy optical telescope element manager for Webb at Goddard.
“The completion of this last test on its mirrors is especially exciting because of how close we are to launch later this year,” Keski-Kuha added.
In August, Webb is slated to be moved by ship from Northrop Grumman’s facility in California to Europe’s spaceport near Kourou in South America via the Panama Canal from where it is scheduled for launch on 31 October.
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