The James Webb Space Telescope is a space telescope that will be the successor to the Hubble Space Telescope.The JWST will provide greatly improved resolution and sensitivity over the Hubble, and will enable a broad range of investigations across the fields of astronomy and cosmology. The JWST's primary mirror is composed of 18 hexagonal mirror segments made of gold-coated beryllium. These combine to create a 6.5-meter (21 ft 4 in) diameter mirror that is much larger than the Hubble's 2.4-meter (7 ft 10 in) mirror.