Editor’s Note: This post was updated to clarify the strength vs. stiffness of beryllium.
Last week, the Webb team began moving the observatory’s individual mirror segments out of their launch positions. Today, we hear from Erin Wolf, Webb program manager at Ball Aerospace, about the completion of that process:
“Today, the James Webb Space Telescope team completed the mirror segment deployments. As part of this effort, the motors made over a million revolutions this week, controlled through 20 cryogenic electronics boxes on the telescope. The mirror deployment team incrementally moved all 132 actuators located on the back of the primary mirror segments and secondary mirror. The primary mirror segments were driven 12.5 millimeters away from the telescope structure. Using six motors that deploy each segment approximately half the length of a paper clip, these actuators clear the mirrors from their launch restraints and give each segment enough space to later be adjusted in other directions to the optical starting position for the upcoming wavefront alignment process. The 18 radius of curvature (ROC) actuators were moved from their launch position as well. Even against beryllium’s bending stiffness per weight, which is six times greater than that of ordinary steel, these ROC actuators individually shape the curvature of each mirror segment to set the initial parabolic shape of the primary mirror.
“Next up in the wavefront process, we will be moving mirrors in the micron and nanometer ranges to reach the final optical positions for an aligned telescope. The process of telescope alignment will take approximately three months.”
—Erin Wolf, James Webb Space Telescope Program Manager, Ball Aerospace