The sole secondary mirror that will fly aboard NASA's James Webb Space Telescope was installed onto the telescope at NASA's Goddard Space Flight Center in Greenbelt, Maryland, on March 3, 2016.
The Webb telescope uses many mirrors to direct incoming light into the telescope's instruments. The secondary mirror is called the secondary mirror because it is the second surface the light from the cosmos hits on its route into the telescope.
In this photo, engineers are seen installing the secondary mirror onto the telescope.
Credits: NASA/Goddard/Chris Gunn
NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission.