The James Webb Space Telescope (JWST), previously known as Next Generation Space Telescope (NGST), is a major space observatory under construction and scheduled to launch in October 2018. The JWST will offer unprecedented resolution and sensitivity from long-wavelength (orange-red) visible light, through near-infrared to the mid-infrared (0.6 to 27 micrometers), and is a successor instrument to the Hubble Space Telescope and the Spitzer Space Telescope. While Hubble has a -meter () mirror, the JWST features a larger and segmented 6.5-meter (21 ft) diameter primary mirror and will be located near the Earth–Sun L2 point. A large sunshield will keep its mirror and four science instruments below K () .