MIRI integrated with ISIM showing the thermal heat shield (view 1)
MIRI will detect emission in the mid-infrared range and thermal emission from the Integrated Science Instrument Module (ISIM) structure could interfere with these measurements. For this reason, MIRI is actively cooled to about 7 Kelvin (-266 °C) and wrapped in an aluminized thermal shield. The shield - the silver structure visible in this photograph - will also help deflect any other stray thermal light. The other three instruments, that all operate in the near infrared wavelength region, and the ISIM - the black structure - will be cooled to about 40K.