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Official site of the design, build, test and launch of JWST.


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Mid-Infrared Instrument (MIRI)

The Mid-Infrared Instrument (MIRI) has both a camera and a spectrograph that sees light in the mid-infrared region of the electromagnetic spectrum, with wavelengths that are longer than our eyes see.

Instrument wavelength ranges

MIRI covers the wavelength range of 5 to 28 microns. Its sensitive detectors will allow it to see the redshifted light of distant galaxies, newly forming stars, and faintly visible comets as well as objects in the Kuiper Belt. MIRI's camera will provide wide-field, broadband imaging that will continue the breathtaking astrophotography that has made Hubble so universally admired. The spectrograph will enable medium-resolution spectroscopy, providing new physical details of the distant objects it will observe. (Read more about spectroscopy on the NIRSpec page.)

This image shows the installation of MIRI into the instrument module.

Key Science Instrument Installed into Webb Structure

The integrated instrument module:

JWST Team Photo with Completed Flight Instrument module


MIRI is being built by the MIRI Consortium, a group that consists of scientists and engineers from European countries, a team from the Jet Propulsion Lab in California, and scientists from several U.S. institutions.

Links & Resources:


Technical Details for MIRI:

The MIRI has three Arsenic-doped Silicon (Si:As) detector arrays. The camera module provides wide-field broadband imagery, and the spectrograph module provides medium-resolution spectroscopy over a smaller field of view compared to the imager. The nominal operating temperature for the MIRI is 7K. This level of cooling cannot be attained using the passive cooling provided by the Thermal Management Subsystem. Instead, there is a two-step process: A Pulse Tube precooler gets the instrument down to 18K; and a Joule-Thomson Loop heat exchanger knocks it down to 7K.