The James Webb Space Telescope is the largest, most powerful and most technologically challenging space telescope ever built.
The Webb Telescope is so large; it must be folded like origami to fit inside its rocket fairing for the ride into space. Once in space, unfolding and readying Webb for science is a complex process that will take about six months.
Webb is designed to see the most distant galaxies in the Universe and study how galaxies evolved over cosmic time. Webb will study planets orbiting other stars looking for the chemical signatures of the building blocks of life. Webb will also study planets within our own solar system.
The Webb Telescope Mission is an international space telescope program led by NASA with its partners, the European Space Agency and the Canadian Space Agency.
The James Webb Space Telescope (sometimes called JWST or Webb) is an orbiting infrared observatory that will complement and extend the discoveries of the Hubble Space Telescope, with longer wavelength coverage and greatly improved sensitivity. The longer wavelengths enable Webb to look much closer to the beginning of time and to hunt for the unobserved formation of the first galaxies, as well as to look inside dust clouds where stars and planetary systems are forming today.
The Premier Observatory of the Next Decade
The James Webb Space Telescope will be a large infrared telescope with a 6.5-meter primary mirror. The telescope will be launched on an Ariane 5 rocket from French Guiana in 2021.
Webb will be the premier observatory of the next decade, serving thousands of astronomers worldwide. It will study every phase in the history of our Universe, ranging from the first luminous glows after the Big Bang, to the formation of solar systems capable of supporting life on planets like Earth, to the evolution of our own Solar System.
Webb was formerly known as the “Next Generation Space Telescope” (NGST); it was renamed in September 2002 after a former NASA administrator, James Webb.
Webb is an international collaboration between NASA, the European Space Agency (ESA), and the Canadian Space Agency (CSA). The NASA Goddard Space Flight Center is managing the development effort. The main industrial partner is Northrop Grumman; the Space Telescope Science Institute will operate Webb after launch.
Several innovative technologies have been developed for Webb. These include a primary mirror made of 18 separate segments that unfold and adjust to shape after launch. The mirrors are made of ultra-lightweight beryllium. Webb’s biggest feature is a tennis court sized five-layer sunshield that attenuates heat from the Sun more than a million times. The telescope’s four instruments – cameras and spectrometers – have detectors that are able to record extremely faint signals. One instrument (NIRSpec) has programmable microshutters, which enable observation up to 100 objects simultaneously. Webb also has a cryocooler for cooling the mid-infrared detectors of another instrument (MIRI) to a very cold 7 K so they can work.
For more, read Comparing the Hubble and James Webb Space Telescopes.