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Infrared Radiometer

NSSDCA ID: 1962-041A-02

Mission Name: Mariner 2
Principal Investigator:Dr. Gerry Neugebauer


The Infrared (IR) Radiometer on Mariner 2 was designed to measure the radiation temperatures of small areas of Venus in the 8.4 (8.0 - 9.0) and 10.4 (10.0 - 10.8) micrometer bands in order to study the temperature and atmospheric conditions and the cloud layer structure.

The system was rigidly mounted to the microwave antenna and had a field of view of 0.9 x 0.9 degrees. Optically, the IR Radiometer consisted of two similar lens systems whose axes were separated by 45 degrees. One system, establishing the chopping reference, viewed dark space, and the other viewed the planet, scanning the same surface area of Venus as the Microwave Radiometer. The energy through the two systems was combined into a single chopped beam that was in turn split by a dichroic filter into two perpendicular beams that were incident on two germanium-immersed thermistor bolometer detectors. The uncooled sensitive area of the detectors was 0.15 x 0.15 mm.

The accuracy of the radiation temperatures obtained varied from 2 degrees for source temperatures near 200 K to 10 degrees for source temperatures near 500 K. A plate held at a known temperature was periodically scanned in flight as a calibration. Three successful scans were accomplished during planetary flyby on December 14, 1962.

Alternate Names

  • Mariner2/InfraredRadiometer

Facts in Brief

Mass: 1.3 kg
Power (avg): 2.4 W

Funding Agency

  • NASA-Office of Space Science Applications (United States)


  • Planetary Science: Atmospheres

Additional Information

Questions and comments about this experiment can be directed to: Dr. David R. Williams



NameRoleOriginal AffiliationE-mail
Dr. Gerry NeugebauerGeneral ContactCalifornia Institute of
Dr. Gerry NeugebauerPrincipal InvestigatorCalifornia Institute of

Selected References

  • Chase, S. C., et al., The Mariner 2 infrared radiometer experiment, J. Geophys. Res., 68, No. 22, 6157-6169, doi:10.1029/JZ068i022p06157, Nov. 1963.
  • Chase, S. C., et al., Mariner II: Preliminary reports on measurements of Venus, infrared radiometer, Science, 139, No. 3558, 907-908, doi:10.1126/science.139.3558.907, Mar. 1963.
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