More Information



MIRI provides four basic capabilities:

  Imaging nine photometric bands from 5 to 28 μm , λ/Δλ ~ 5, FOV 74" X 113"
  Lo-res Spectroscopy λ/Δλ ~ 100 at 7.5μm, range of 5 to 12 μm, slit 0.51 X 4.7"
  Hi-res Spectroscopy λ/Δλ ~ 2070 - 3730, range of 4.9 to 28.8 μm, IFU with FOVs of 3.7" to 7.7"
  Coronagraphy four-quadrant phase masks at 10.65, 11.4, & 15.5 μm, Lyot at 23μm



MIRI Overall Layout

The optical module (OM), containing the imager, spectrometers, and coronagraphs, is within the JWST integrated science instrument module (ISIM) with a nominal 40K surrounding temperature. The OM and focal plane modules (FPMs) are brought to a lower temperature by a pulse-tube-based mechanical cooler, with compressors (CCA) and control electronics (CCE) in the spacecraft and refrigerant lines (RLDA) to bring cold gas to a Joule-Thompson (JT) expander near the OM. The instrument mechanisms are controlled by the instrument control electronics (ICE), and the focal planes are operated by the focal plane electronics (FPE), both of which are in region 2, a warm module placed near the ISIM.  


Optical Module

The optical module has been designed and constructed by the MIRI European Consortium. Infrared radiation from the telescope enters through the input optics and calibration structure and is divided at the focal plane (within the instrument) between the imager (which also carries the low resolution spectrometer and coronagraphs) and the moderate resolution spectrometer.

The MIRI Imager


The MIRI Spectrometer (MRS)


The MIRI Focal Plane Modules (FPMs)

The MIRI focal planes were produced by Raytheon Vision Systems (RVS) for JPL, where they have been mounted into focal plane modules that can be bolted to the OM. Each detector array is 1024 X 1024 pixels of Si:As IBC devices. The FPMs provide shielding and thermal isolation to allow annealing.


The MIRI Cooling System

The cooler is built by Northrop Grumman Aerospace Systems, under contract to JPL. The cooling system includes many components, which are under the responsibility of NGAS, Goddard, and Rutherford Appleton Laboratory as well as JPL.