Webb Telescope Successfully Unfolds Secondary Mirror in Critical Milestone
The James Webb Space Telescope reaches a crucial milestone as a motor-driven tripod unfolds to position its secondary mirror perfectly. This successful deployment brings the $10 billion observatory one step closer to full optical functionality.
The James Webb Space Telescope achieves another major milestone as a motor-driven tripod unfolds as planned, moving a 2.4-foot-wide secondary mirror into position to reflect collected starlight down to the observatory's scientific instruments. While the prior deployment of the sunshield marks the most technically challenging hurdle for Webb's initial activation, positioning this secondary mirror proves equally critical to the success of the $10 billion mission.
To fit inside the nose cone of its European Space Agency-supplied Ariane 5 rocket, the secondary mirror assembly consists of three 25-foot-long struts that must remain folded up during launch. On Wednesday, flight engineers send commands to unlatch the hinged legs of the tripod so a motor drives them open, completing the 11-minute procedure without a hitch to the relief of the mission operations team.
Since its launch on Christmas Day, engineers successfully carry out a string of crucial steps, deploying the telescope's main antenna, radiators, and sunshield needed to cool the mirrors and instruments enough to register faint infrared light. With the secondary mirror now in place, light captures by Webb's massive 21.3-foot-wide primary mirror bounces up to the newly positioned secondary mirror and then back down to a third mirror behind the primary to begin scientific observations.