HIRDLS INSTRUMENT
The HIRDLS instrument is an infrared limb-sounding radiometer. The dimensions of the instrument are approximately 1330 mm high by 1500 mm wide by 1185 mm deep. The outer structure is constructed of aluminum honeycomb with carbon composite face sheets. Within the outer structure is an optical bench assembly carrying a telescope and 2-axis scanning mirror, a detector dewar assembly, a precision internal blackbody calibrator, and a gyroscope package. Incoming radiation is chopped by a rotating chopper at 500 Hz. When the chopper is closed the detectors are presented with a cold space image through a space view port. A Stirling cycle cooler, mounted on the side of the instrument with its own integral radiator, maintains the detectors at their 65 K operating temperature. A sunshield and an aperture door ensure that direct sunlight does not enter the radiometer.