NASA’s James Webb Space Telescope

Cryogenic testing has now been completed for the final 6 primary mirror segments and a secondary mirror that will fly on NASA’s James Webb Space Telescope.
Cryogenic testing has now been completed for the final 6 primary mirror segments and a secondary mirror that will fly on NASA’s James Webb Space Telescope.
The process took years and broke new ground in the spheres of manufacturing and testing of large mirrors. The Webb telescope has 21 mirrors, with 18 mirror segments working together as a large (6.5-metre) primary mirror. Each individual mirror segment now has been successfully tested to operate at 40 Kelvin (-233°C).