The James Webb Space Telescope (JWST) was conceived as the scientific successor to the Hubble Space Telescope (HST), and to the Spitzer Space Telescope.1 Answering scientific questions beyond the grasp of these previous missions requires a large and flexible infrared observatory. In turn, these considerations motivated the selection of a deployable, segmented primary mirror, and an L2 orbit far from the earth.
JWST has four Scientific Instruments (SIs). These are as follows: Near-Infrared Camera (NIRCam), Near-Infrared Spectrograph (NIRSpec), Mid-
1JWST was named in honor of James E. Webb, the administrator who directed NASA during the Apollo era.
Infrared Instrument (MIRI), and Fine Guidance Sensor with Tunable Imager (FGS/TI). The four SIs are located in the Integrated Science Instruments Module (ISIM), which is located behind the primary mirror in Fig. 1. In total, the SIs incorporate 16 Rockwell HAWAII-2RG mercury--cadmium -telluride (HgCdTe) Sensor Chip Assemblies (SCAs), and 3 Raytheon SB-305 Si:As SCAs (see Fig. 2).
In this paper, we briefly summarize JWST's science goals to provide context, and then discuss the mission and each of the SIs with an emphasis on detectors. Readers who are more interested in JWST's science goals may wish to see one of the more recent articles on the subject .
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