The James Webb Space Telescope (JWST) is a 6.5 meter (21 ft) NASA/European Space Agency/CSA space-based Infrared telescope under construction, planned for launch in March 2021 (as of June 2018--the launch date has been delayed several times) to the Earth-Sun L2 Lagrangian Point. Its lifetime will be limited by the fuel it carries and uses to keep it from straying from its orbit. A five-and-a-half-year program is targeted and a ten-year life is hoped for. Instruments:
One observation target is Spectroscopy of Extra-Solar Planets. NIRISS can operate in a mode termed SOSS, for Single-Object Slitless Spectroscopy, aimed at Differential Spectroscopy for observing the Light Curves of transiting exoplanets. MIRI offers medium-Resolution (MRS mode, offering resolutions of 1500-3500) which is hoped to provide Direct Imaging of exoplanets. NIRSpec offers several Gratings, with grating labeled G395 offering a spectral resolution of as much as 2700.