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NASA’s James Webb Space Telescope completes primary mirror test

Christian Fernsby |
Northrop Grumman Space Systems has successfully completed the deployment of the Primary Mirror on NASA’s next-generation space telescope, the James Webb Space Telescope.

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During the deployment test, Northrop Grumman personnel instructed the spacecraft to deploy – and then securely latch – the Primary Mirror to the position which it will need to be in to conduct science. The Primary Mirror will only be deployed once more – and that’ll be before shipment to the launch site.

The Primary Mirror is 21 feet and 4 inches across. The mirror on the James Webb Space Telescope is the largest ever built for NASA. The mirror has a diameter 2.7 times the size of the one on the Hubble Space Telescope.

The reason that the Mirror folds on the telescope is that when deployed, the mirror is too large to fit inside of the 16 foot payload fairing during launch. On the Primary Mirror, there are two “wings,” one on the left and the other on the right. Each wing has to deploy for the telescope to operate properly.

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