The Webb Telescope's mirrors are coated in an extremely thin film of gold. This gold layer, only a few millionths of an inch thick, enables the mirrors to best reflect the infrared light the telescope seeks. The thinner the layer, the better off the telescope will be -- every bit of weight counts when a telescope as big as Webb is being lifted into space by a rocket. Join us at Quantum Coating in New Jersey, where engineers are vaporizing gold to apply a thin, even layer to the telescope's mirrors.
"Behind the Webb" is an ongoing series that follows the construction of the Webb Space Telescope, Hubble's successor. Find more episodes at Hubblesite.org.
"Behind the Webb" archive http://webbtelescope.org/webb_telescope/behind_the_webb/archive/