James Webb Space Telescope Primary Mirror Backplane Support Structure (image) National Institute of Standards and Technology (NIST) Share Print E-Mail Caption This image shows the complete Primary Mirror Backplane Support Structure (PMBSS) for the James Webb Space Telescope (JWST). The inset shows the location of the four support mounts of the type that NIST measured. For scale, note the assembly technician in the photo. The PMBSS is the largest single structure on the JWST and also the largest precision metrology structure that has ever been built for a NASA program. Credit NASA Usage Restrictions None Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.