On January 4, NASA operators successfully completed the deployment of the James Webb Space Telescope's sunshield—the most intricate step in its elaborate unfolding process. With this milestone achieved, the team now advances to deploying the secondary and primary mirrors.
The James Webb Space Telescope (JWST) continues its precise deployment in space. Over Monday and Tuesday, mission controllers deployed its massive five-layer sunshield, comparable in size to a tennis court. As NASA experts explain, each layer is as thin as a human hair and coated with reflective metal to shield the observatory from heat emitted by the Sun, Earth, and Moon.
JWST's primary mirror, NASA's largest ever at 6.5 meters in diameter, comprises 18 hexagonal beryllium segments—a lightweight metal ideal for space. Each segment is coated with gold for optimal reflectivity across a broad spectrum of wavelengths.
The mirror assembly includes a central section flanked by two 'wings' that were folded for launch within the Ariane 5 rocket's fairing. Deployment now involves unfolding these wings.
The secondary mirror, 0.74 meters wide, is the next light path after the primary and sits atop extendable struts. Its deployment precedes the primary mirror's, with the full process starting this weekend and spanning about 10 days.
Assuming smooth progress, JWST will arrive at the Sun-Earth L2 Lagrange point about 29 days post-launch on January 23. The team will then align the 18 primary mirror segments to function as one seamless surface.
Using the telescope's Near-Infrared Camera (NIRCam), which detects wavefront distortions with exceptional precision, 126 actuators will adjust each segment—positioning, tilting, or curving them as needed based on real-time data.
Subsequent weeks will focus on final calibrations and commissioning. Scientific observations are slated to begin this summer, supporting a mission lifespan of 5 to 10 years.
