Mid-Infrared Instrument

MIRI, or the Mid-Infrared Instrument, is an instrument on the James Webb Space Telescope.^[1] MIRI is a camera and a spectrograph that observes mid to long infrared radiation from 5 to 28 microns.^[1] It also has coronagraphs, especially for observing exoplanets.^[2] Whereas most of the other instruments on Webb can see from the start of near infrared, or even as short as orange visible light, MIRI can see longer wavelength light.^[1]

MIRI uses silicon arrays doped with arsenic to make observations at these wavelengths.^[1] The imager is designed for wide views but the spectrograph has a smaller view.^[1] Because it views the longer wavelengths it needs to be cooler than the other instruments (see Infrared astronomy), and it has an additional cooling system.^[1] The cooling system for MIRI includes a Pulse Tube precooler and a Joule-Thomson Loop heat exchanger.^[1] This allowed MIRI to be cooled down to a temperature of 7 kelvins during operations in space.^[1]

MIRI was built by the MIRI Consortium, a group that consists of scientists and engineers from 10 different European countries (The United Kingdom, France, Belgium, the Netherlands, Germany, Spain, Switzerland, Sweden, Denmark and Ireland) with the United Kingdom heading the European consortium,^[3] as well as a team from the Jet Propulsion Lab in California, and scientists from several U.S. institutions.^[4]