Near Infrared Camera and Multi-Object Spectrometer

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The Near Infrared Camera and Multi-Object Spectrometer (NICMOS) is a scientific instrument for infrared astronomy, installed on the Hubble Space Telescope (HST), operating from 1997 to 1999, and from 2002 to the present.

NICMOS is an spectrometer built by Ball Aerospace that allows the HST to observe infrared light, with wavelengths between 0.8 and 2.5 micrometres, providing imaging and spectroscopy capabilities. NICMOS contains a 256x256 pixels array of Hg_0.554Cd_0.446Te infrared detectors, in four independent 128x128 quadrants.

NICMOS was installed on Hubble during its second servicing mission in 1997, when two previous spectrograph instruments were replaced by the Space Telescope Imaging Spectrograph.

When conducting infrared measurements, it is necessary to keep the infrared detectors cooled to avoid having infrared interference from the detector's own heat emissions, so the NICMOS was designed to fit inside a cryogenic dewar, cooling the detector with a block of solid nitrogen. When NICMOS was installed in 1997, the dewar contained a 230 pound (104 kg) block of nitrogen ice. However, due to unforseen design problems, the dewar ran out of nitrogen coolant after less than two years, and had to stop operation. However, during Hubble Service Mission 3B in 2002, a cryocooler was installed on the Hubble that provides additional refrigeration to the NICMOS through a refrigerated neon loop, allowing it to resume observation measurements.