The ISIM & Instruments
A rare view of the instruments being lowered into the Webb telescope at NASA/Goddard. Webb's science instruments were installed in a surgically precise operation. Read more about the ISIM installation on NASA.gov Credit: NASA/Chris Gunn
Webb's instruments are contained within the Integrated Science Instrument Module (ISIM) which is one of three major elements that comprise the James Webb Space Telescope Observatory flight system. The others are the Optical Telescope Element (OTE) and the Spacecraft Element (Spacecraft Bus and Sunshield).
The ISIM is the heart of the James Webb Space Telescope, what engineers call the main payload. It houses the four main instruments that detect light from distant stars and galaxies, and planets orbiting other stars.
The ISIM includes the following instruments:
- Near-Infrared Camera, or NIRCam - provided by the University of Arizona
- Near-Infrared Spectrograph, or NIRSpec - provided by ESA, with components provided by NASA/GSFC.
- Mid-Infrared Instrument, or MIRI - provided by the European Consortium with the European Space Agency (ESA), and by the NASA Jet Propulsion Laboratory (JPL)
- Fine Guidance Sensor/ Near InfraRed Imager and Slitless Spectrograph , or FGS/NIRISS - provided by the Canadian Space Agency.
IN DEPTH: Technical Details about the ISIM
Integrating four major instruments and numerous subsystems into one payload, the ISIM, was a daunting endeavor. To simplify integration, engineers divided the ISIM into three regions.
The "region 1" component is the cryogenic instrument module. This chills the detectors down to 39 K, a necessary first-stage cooling effort so that the spacecraft's own heat doesn't interfere with the infrared light (a form of heat) detected from distant cosmic sources. The ISIM/OTE Thermal Management Subsystem provides passive cooling. Other devices get the detectors even colder.
The "region 2" component is the ISIM Electronics Compartment, which provides the mounting surfaces and ambient thermally controlled environment for the instrument control electronics.
The "region 3" component, located within the Spacecraft Bus, is the ISIM Command and Data Handling subsystem, with integral ISIM flight Software, and the MIRI cryocooler compressor and control electronics.
- View our ISIM and instruments galleries.
- View a play list of time-lapse movies of Webb being built and tested at NASA/Goddard and NASA/JSC.
- Video: Go behind the scenes of cryogenic testing of the ISIM Structure with the following video.