Webb’s cameras and spectrographs need to be cold. Really cold. They need to be so cold that engineers created specialized mechanisms to reduce their heat in addition to the shade provided by the large sunshield. One such mechanism is the Aft Deployable Instrument Radiator, or ADIR. ADIR channels the heat out of Webb’s instruments and dumps it into deep space.
Today’s deployment started when a launch lock was released; the ADIR panel then swung away from the telescope into position for it to operate properly. Now this cool telescope will have even cooler instruments.
Tomorrow the Webb team will begin deployment of the port wing of the main mirror, which holds three mirror segments. We will be watching!