The Integrated Science Instrument Module (ISIM) is a framework that provides electrical power, computing resources, cooling capability as well as structural stability to the Webb telescope.
It is made with bonded graphite-epoxy composite attached to the underside of Webb's telescope structure.
The ISIM holds the four science instruments and a guide camera.

NIRCam (Near InfraRed Camera) is an infrared imager which will have a spectral coverage ranging from the edge of the visible (0.6 micrometers) through the near infrared (5 micrometers).
NIRCam will also serve as the observatory's wavefront sensor, which is required for wavefront sensing and control activities.
NIRCam was built by a team led by the University of Arizona, with principal investigator Marcia J. Rieke.
The industrial partner is Lockheed-Martin's Advanced Technology Center located in Palo Alto, California.

NIRSpec (Near InfraRed Spectrograph) will also perform spectroscopy over the same wavelength range.
It was built by the European Space Agency at ESTEC in Noordwijk, Netherlands.
The leading development team includes members from Airbus Defence and Space, Ottobrunn and Friedrichshafen, Germany, and the Goddard Space Flight Center; with Pierre Ferruit (École normale supérieure de Lyon) as NIRSpec project scientist.
The NIRSpec design provides three observing modes: a low-resolution mode using a prism, an R~1000 multi-object mode, and an R~2700 integral field unit or long-slit spectroscopy mode.
Switching of the modes is done by operating a wavelength preselection mechanism called the Filter Wheel Assembly, and selecting a corresponding dispersive element (prism or grating) using the Grating Wheel Assembly mechanism.
Both mechanisms are based on the successful ISOPHOT wheel mechanisms of the Infrared Space Observatory.
The multi-object mode relies on a complex micro-shutter mechanism to allow for simultaneous observations of hundreds of individual objects anywhere in NIRSpec's field of view.
The mechanisms and their optical elements were designed, integrated and tested by Carl Zeiss Optronics GmbH of Oberkochen, Germany, under contract from Astrium.

MIRI (Mid-InfraRed Instrument) will measure the mid-to-long-infrared wavelength range from 5 to 27 micrometers.
It contains both a mid-infrared camera and an imaging spectrometer.
MIRI was developed as a collaboration between NASA and a consortium of European countries, and is led by George Rieke (University of Arizona) and Gillian Wright (UK Astronomy Technology Centre, Edinburgh, part of the Science and Technology Facilities Council (STFC)).
MIRI features similar wheel mechanisms as NIRSpec which are also developed and built by Carl Zeiss Optronics GmbH under contract from the Max Planck Institute for Astronomy, Heidelberg.
The completed Optical Bench Assembly of MIRI was delivered to Goddard Space Flight Center in mid-2012 for eventual integration into the ISIM.
The temperature of the MIRI must not exceed 6 Kelvin (K): a helium gas mechanical cooler sited on the warm side of the environmental shield provides this cooling.

FGS/NIRISS (Fine Guidance Sensor and Near Infrared Imager and Slitless Spectrograph), led by the Canadian Space Agency under project scientist John Hutchings (Herzberg Institute of Astrophysics, National Research Council (Canada)), is used to stabilize the line-of-sight of the observatory during science observations.
Measurements by the FGS are used both to control the overall orientation of the spacecraft and to drive the fine steering mirror for image stabilization.
The Canadian Space Agency is also providing a Near Infrared Imager and Slitless Spectrograph (NIRISS) module for astronomical imaging and spectroscopy in the 0.8 to 5 micrometer wavelength range, led by principal investigator René Doyon at the Université de Montréal.
Because the NIRISS is physically mounted together with the FGS, they are often referred to as a single unit; however, they serve entirely different purposes, with one being a scientific instrument and the other being a part of the observatory's support infrastructure
The Integrated Science Instrument Module (ISIM) is a framework that provides electrical power, computing resources, cooling capability as well as structural stability to the Webb telescope. It is made with bonded graphite-epoxy composite attached to the underside of Webb's telescope structure. The ISIM holds the four science instruments and a guide camera.
NIRCam (Near InfraRed Camera) is an infrared imager which will have a spectral coverage ranging from the edge of the visible (0.6 micrometers) through the near infrared (5 micrometers). NIRCam will also serve as the observatory's wavefront sensor, which is required for wavefront sensing and control activities. NIRCam was built by a team led by the University of Arizona, with principal investigator Marcia J. Rieke. The industrial partner is Lockheed-Martin's Advanced Technology Center located in Palo Alto, California.
NIRSpec (Near InfraRed Spectrograph) will also perform spectroscopy over the same wavelength range. It was built by the European Space Agency at ESTEC in Noordwijk, Netherlands. The leading development team includes members from Airbus Defence and Space, Ottobrunn and Friedrichshafen, Germany, and the Goddard Space Flight Center; with Pierre Ferruit (École normale supérieure de Lyon) as NIRSpec project scientist. The NIRSpec design provides three observing modes: a low-resolution mode using a prism, an R~1000 multi-object mode, and an R~2700 integral field unit or long-slit spectroscopy mode. Switching of the modes is done by operating a wavelength preselection mechanism called the Filter Wheel Assembly, and selecting a corresponding dispersive element (prism or grating) using the Grating Wheel Assembly mechanism. Both mechanisms are based on the successful ISOPHOT wheel mechanisms of the Infrared Space Observatory. The multi-object mode relies on a complex micro-shutter mechanism to allow for simultaneous observations of hundreds of individual objects anywhere in NIRSpec's field of view. The mechanisms and their optical elements were designed, integrated and tested by Carl Zeiss Optronics GmbH of Oberkochen, Germany, under contract from Astrium.
MIRI (Mid-InfraRed Instrument) will measure the mid-to-long-infrared wavelength range from 5 to 27 micrometers. It contains both a mid-infrared camera and an imaging spectrometer. MIRI was developed as a collaboration between NASA and a consortium of European countries, and is led by George Rieke (University of Arizona) and Gillian Wright (UK Astronomy Technology Centre, Edinburgh, part of the Science and Technology Facilities Council (STFC)). MIRI features similar wheel mechanisms as NIRSpec which are also developed and built by Carl Zeiss Optronics GmbH under contract from the Max Planck Institute for Astronomy, Heidelberg. The completed Optical Bench Assembly of MIRI was delivered to Goddard Space Flight Center in mid-2012 for eventual integration into the ISIM. The temperature of the MIRI must not exceed 6 Kelvin (K): a helium gas mechanical cooler sited on the warm side of the environmental shield provides this cooling.
FGS/NIRISS (Fine Guidance Sensor and Near Infrared Imager and Slitless Spectrograph), led by the Canadian Space Agency under project scientist John Hutchings (Herzberg Institute of Astrophysics, National Research Council (Canada)), is used to stabilize the line-of-sight of the observatory during science observations. Measurements by the FGS are used both to control the overall orientation of the spacecraft and to drive the fine steering mirror for image stabilization. The Canadian Space Agency is also providing a Near Infrared Imager and Slitless Spectrograph (NIRISS) module for astronomical imaging and spectroscopy in the 0.8 to 5 micrometer wavelength range, led by principal investigator René Doyon at the Université de Montréal. Because the NIRISS is physically mounted together with the FGS, they are often referred to as a single unit; however, they serve entirely different purposes, with one being a scientific instrument and the other being a part of the observatory's support infrastructure
James Webb Space Telescope