James Webb telescope's MIRI instrument goes super-cold The Mid-Infrared Instrument on the James Webb Space telescope is now at its super-low operating temperature. A key difference, though, is that Webb will be tuned to see the Universe at longer wavelengths, in the infrared. This means it must be protected from all heat sources, including its own hardware, which would otherwise glow in that same portion of the light spectrum it wants to detect. To this end, Webb deployed a giant sunshield shortly after it was launched on 25 December. This tennis court-sized membrane put all the important parts of the telescope in the shade.