JWST's golden mirror
The James Webb Space Telescope is pictured standing tall and glimmering gold inside the cleanroom of NASA's Goddard Space Flight Center in Greenbelt, Maryland.
The primary mirror is composed of 18 hexagonal-shaped mirror segments, each 1.32 metres in diameter and weighing approximately 20 kilograms.
The convex secondary mirror is about 0.74 metres in diameter.
Each of the telescope's mirrors are covered in a microscopically thin layer of gold, which optimises them for reflecting infrared light – the primary wavelength of light this telescope will observe. To ensure the mirrors are both strong and light, the team made the mirrors out of beryllium.
(Image sourced from here.)