What is the required operating temperature for the Mid-Infrared Instrument (MIRI) on the JWST, achieved via its specialized cooling system?

Down to about 7 Kelvin

Capturing faint infrared signals from deep space presents a unique thermal challenge because every warm object, including the telescope structure itself, emits infrared radiation. To prevent the telescope's own heat from overwhelming the minuscule signals from distant galaxies, sensitive instruments like the Mid-Infrared Instrument (MIRI) must be kept extraordinarily cold. The JWST achieves this through a massive sunshield combined with an active cryocooler, maintaining MIRI's detectors at operating temperatures down to approximately 7 Kelvin. This level of extreme cooling ensures the detectors are sensitive only to the faint cosmic photons and not the intrinsic warmth of the spacecraft.