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Heat Capacity Mapping Radiometer

NSSDCA ID: 1978-041A-01

Mission Name: HCMM
Principal Investigator:Dr. William L. Barnes


The objectives of the Heat Capacity Mapping Radiometer (HCMR) were (1) to produce thermal maps at the optimum times for making thermal-inertia studies for discrimination of rock types and mineral resources location, (2) to measure plant-canopy temperatures at frequent intervals to determine the transpiration of water and plant life, (3) to measure soil-moisture effects by observing the temperature cycle of soils, (4) to map thermal effluents, both natural and man-made, (5) to investigate the feasibility of geothermal source location by remote sensing, and (6) to provide frequent coverage of snow fields for water runoff prediction. The HCMR transmitted analog data in real time to selected receiving stations. The radiometer was similar to the surface composition mapping radiometer (SCMR) of Nimbus 5 (72-097A). The HCMR had a small instantaneous geometric field of view of 0.83 mrad, high radiometric accuracy, and a wide 716-km swath coverage on the ground so that selected areas were covered within the 12-h period corresponding to the maximum and minimum of temperature observed. The instrument operated in two channels, 10.5 to 12.5 micrometers (IR) and 0.55 to 1.1 micrometers (visible). The spatial resolution was approximately 600 m at nadir for the IR channel, and 500 m for the visible channel. The instrument utilized a radiation cooler to cool the two Hg-Cd-Te detectors to 115 K. The experiment included an analog multiplexer that accepted the analog outputs of the detectors and multiplexed them in a form suitable for transmission by the spacecraft S-band transmitter. The instrument performed satisfactorily until the spacecraft operations terminated on September 30, 1980. More detailed information can be found in the "Heat Capacity Mapping Mission Users' Guide" (TRF B30282), available from NSSDC. Data are available from NSSDC and Earthnet Users Services, via Galileo Galilei, C.P. 64, 00044 Frascati, Italy.

Alternate Names

  • HCMR

Facts in Brief

Mass: 38.9 kg

Funding Agency

  • NASA-Office of Space and Terrestrial Applications United States


  • Earth Science: Atmospheric Dynamics
  • Earth Science: Land Surface Processes

Additional Information

Questions and comments about this experiment can be directed to: Coordinated Request and User Support Office



NameRoleOriginal AffiliationE-mail
Dr. William L. BarnesPrincipal InvestigatorNASA Goddard Space Flight
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