Abstract

The long-awaited James Webb Space Telescope is planned for launch by Oct. 31, 2021. With its 6.5 m deployable primary mirror, and cameras and spectrometers covering 0.6 to 28 µm, it promises extraordinary improvements in observing capabilities. Webb will be able to observe the first objects that formed after the Big Bang, the growth of galaxies, the formation of stars and planetary systems, individual exoplanets through coronography and transit spectroscopy, and all objects in the Solar System from Mars on out. It could observe a 1 cm2 bumblebee at the distance of the Moon, in reflected sunlight and thermal emission. I will review the observatory capabilities and planned observing program, and illustrate the history of the concept from 1988 to now. The Webb is a joint project of NASA with the European and Canadian space agencies. Europe is providing the Ariane 5 launch vehicle and the near IR spectrometer (NIRSpec), and Gillian Wright at the UKATC in Edinburgh led the construction of the Mid Infrared Instrument (MIRI).