The Multiple Instrument Chamber
Spitzer's Multiple Instrument Chamber contains the cold parts of Spitzer's three scientific instruments: Infrared Array Camera, Infrared Spectrograph and Multiband Imaging Photometer. It also houses the pointing calibration reference sensor, which is part of the pointing control system that helps to make sure the telescope is pointing in the right direction. The Multiple Instrument Chamber is built to be so tight that no light can get through, except the light that is directed onto the instruments by the telescope. The chamber is 84 cm in diameter, and 20 cm high. It has an aluminum baseplate and cover, and is attached directly to the cryostat filled with liquid helium.