NASA Completes Mirror Polishing for James Webb Space Telescope

Completion of Webb Telescope mirror polishing represents a major mission milestone. All of the mirrors that will fly aboard NASA's James Webb Space Telescope have been polished so the observatory can see objects as far away as the first galaxies in the universe. The mirrors were polished at Tinsley Laboratories Inc. in Richmond, Calif. to accuracies of less than one millionth of an inch. This accuracy is important for forming the sharpest images when the mirrors cool to -400 degrees farenheit (-240 degrees celsius) in the cold of space.