NASA announced that the mirrors of its James Webb Space Telescope, an advanced space observatory and successor to the Hubble Space Telescope, have been successfully coated with a very thin layer of gold at the New Jersey-based Quantum Coating (QCI).
The coating has been applied for proper reflection of the infrared light from the mirrors into the science instruments of the observatory. It allows the telescope’s infrared eyes to detect dim objects in infrared light.
NASA has reached another milestone by completing the mirror coatings on time. The Webb telescope comprises 21 mirrors, in which 18 mirror segments work together as a single primary mirror. Beryllium has been used to produce the mirror segments. The material has been chosen for its stability at cryogenic temperatures, lightweight and stiffness. Since, bare beryllium is not too reflective of infrared light, each mirror is applied with approximately 0.12 oz of gold coating.
QCI established a new coating facility and a clean room to coat the Webb’s mirror segments. The company has developed 120 nm thick gold coating to offer significant performance in terms of reflectance, stress, durability, cryogenic cycling and uniformity. The Webb telescope mirror coating program commenced in June 2010. The coating process includes heating of gold to its liquid point, which is over 2,500 F and evaporated onto the optical surface of the mirrors.
Source: http://www.nasa.gov/