Practicing Attaching a Mirror Segment (IMAGE) NASA/Goddard Space Flight Center Caption A surrogate mirror segment which is the same hexagonal shape and same mass or weight as one of the primary flight mirrors, is being carefully attached to the a test structure called a "backplane" that will hold 18 of those mirrors on the Webb telescope. Credit NASA/Chris Gunn Usage Restrictions None License Licensed content 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.