INFRARED RADIOMETER
The infrared radiometer was a companion experiment to the microwave instrument and was rigidly mounted to the microwave antenna so that both radiometers would look at the same area of Venus with the same scanning rate. The instrument detected radiation in the 8 to 9 and 10 to 10.8 micron regions of the infrared spectrum.
The infrared radiometer had two optical sensors. As the energy entered the system, it was “chopped” by a rotating disk, alternately passing or comparing emissions from Venus and from empty space. The beam was then split by a filter into the two wavelength regions. The output was then detected, processed, and transmitted to the Earth.
The infrared radiometer measured 6 inches by 2 inches, weighed 2.7 pounds, and consumed 2 watts of power. The instrument was equipped with a calibration plate which was mounted on a superstructure truss adjacent to the radiometer.