NASA recently tested the mirror array of the James Webb Space Telescope by fully deploying the primary mirror into the same configuration that it will have when in space. The telescope is currently set for liftoff in 2021. Technicians and engineers are working diligently to complete a long list of final tests before the observatory can launch.
NASA performed the full mirror deployment test in early March. The test involved commanding the spacecraft’s internal systems to fully extend and latch the massive 21 foot, four-inch primary mirror. That made the mirror appear just as it would after it has been launched into orbit. NASA says the mirror test was performed at Northrop Grumman Space Systems in Redondo Beach, California.
NASA has been increasing the difficulty and complexity of tests for the Webb space telescope since the observatory has been fully assembled. NASA used special gravity offsetting equipment that was attached to the telescope mirror to simulate the zero-gravity environment its mechanisms will operate in when in orbit. The massive mirror array test will be performed one more time just before delivering the space telescope is delivered to the launch site.
How much detail the telescope can see is directly related to the size of the mirror that collects light from the objects it observes. The larger the mirror, the more light it collects, and the better the telescope can see. The mirror of the James Webb is the biggest of its kind that NASA has ever built. The reason the mirror array folds is that it’s so big it can’t fit into any rocket without being folded.
When folded, the James Webb Space Telescope can barely fit inside a 16-foot payload fairing. NASA also noted that the team working on the space telescope in California is currently operating with reduced personnel and shifts due to the coronavirus.