The
James Webb Space Telescope (
JWST), previously known as
Next Generation Space Telescope (
NGST), is a flagship-class
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, and is a successor instrument to the
Hubble Space Telescope and the
Spitzer Space Telescope. The
telescope features a 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 .