Pioneer saturn infrared radiometer: preliminary results.

The effective temperature of Saturn, 94.4 + 3 K, implies a total emission greater than two times the absorbed sunlight. The infrared data alone give an atmospheric abundance of H(2) relative to H(2) + He of 0.85 +/- 0.15. Comparison of infrared and radio occultation data will give a more precise estimate. Temperature at the 1-bar level is 137 to 140 K, and 2.5 K differences exist between belts and zones up to the 0.06-bar level. Ring temperatures range from 60 to 70 K on the south (illuminated) side and from < 60 to 67 K in the planet's shadow. The average temperature of the north (unilluminated) side is approximately 55 K. Titan's 45-micrometer brightness temperature is 80 +/- 10 K.

Mariner 1969: preliminary results of the infrared radiometer experiment.

The thermal energy emitted by Mars was measured in the 8- to 12- and 18- to 25-micrometer bands. The minimum temperature derived for the southern polar cap is 150 degrees K, an indication that the cap is formed by frozen carbon dioxide. No significant temperature fluctuations were detected with a 100-kilometer scale.

Preliminary infrared radiometry of venus from mariner 10.

The intensity of emission at 45 micrometers, measured with high spatial resolution along a single crossing of the Venus disk, is presented. On the average, the observed darkening toward the limb varies nearly linearly with the cosine of the emission angle. The brightness temperature, extrapolated to normal emission, is 255 degrees K. The limb darkening curve, interpreted in a linear approximation, implies that the atmosphere is quite opaque, with an absorption coefficient of 0.24 per kilometer. Changes in curvature present in the limb darkening curve suggest the existence of thermal inhomogeneities with scale comparable to that of the dark markings shown by ultraviolet images.

Preliminary infrared radiometry of the night side of mercury from mariner 10.

The infrared radiometer on Mariner 10 measured the thermal emission from the planet with a spatial resolution element as small as 40 kilometers in a broad wavelength band centered at 45 micrometers. The minimum brightness temperature (near local midnight) in these near-equatorial scans was 100 degrees K. Along the track observed, the temperature declined steadily from local sunset to near midnight, behaving as would be expected for a homogeneous, porous material with a thermal inertia of 0.0017 cal cm(-2) sec(-(1/2)) degrees K(-1), a value only slightly larger than that of the moon. From near midnight to dawn, however, the temperature fluctuated over a range of about 10 degrees K, implying the presence of regions having thermal inertia as high as 0.003 cal cm(-2) sec-(1/2) degrees K(-1).

Infrared radiometry experiment on mariner 9.

The brightness temperatures at 10 and 20 micrometers measured by the Mariner 9 infrared radiometer differ substantially from those predicted by the radiometer results of Mariners 6 and 7. The results indicate a significant latitude-dependent contribution of the atmospheric dust to the observed thermal emission.

Pioneer 10 infrared radiometer experiment: preliminary results.

Thermal maps of Jupiter at 20 and 40 micrometers show structure closely related to the visual appearance of the planet. Peak brightness temperatures of 126 degrees and 145 degrees K have been measured on the South Equatorial Belt, for the 20- and 40-micrometer channels, respectively. Corresponding values for the South Tropical Zone are 120 degrees and 138 degrees K. No asymmetries between the illuminated sunlit and nonilluminated parts of the disk were found. A preliminary discussion of the data, in terms of simple radiative equilibrium models, is presented. The net thermal energy of the planet as a whole is twice the solar energy input.

Infrared thermal mapping of the martian surface and atmosphere: first results.

The Viking infrared thermal mapper measures the thermal emission of the martian surface and atmosphere and the total reflected sunlight. With the high resolution and dense coverage being achieved, planetwide thermal structure is apparent at large and small scales. The thermal behavior of the best-observed areas, the landing sites, cannot be explained by simple homogeneous models. The data contain clear indications for the relevance of additional factors such as detailed surface texture and the occurrence of clouds. Areas in the polar night have temperatures distinctly lower than the CO(2) condensation point at the surface pressure. This observation implies that the annual atmospheric condensation is less than previously assumed and that either thick CO(2) clouds exist at the 20-kilometer level or that the polar atmosphere is locally enriched by noncondensable gases.

Martian north pole summer temperatures: dirty water ice.

Broadband thermal and reflectance observations of the martian north polar region in late summer yield temperatures for the residual polar cap near 205 K with albedos near 43 percent. The residual cap and several outlying smaller deposits are water ice with included dirt; there is no evidence for any permanent carbon dioxide polar cap.

Pioneer 11 infrared radiometer experiment: the global heat balance of jupiter.

Data obtained by the infrared radiometers on the Pioneer 10 and Pioneer 11 spacecraft, over a large range of emission angles, have indicated an effective temperature for Jupiter of 125 degrees +/- 3 degrees K. The implied ratio of planetary thermal emission to solar energy absorbed is 1.9+/-0.2, a value not significantly different from the earth-based estimate of 2.5+/-0.5.

Results from the Mars Global Surveyor Thermal Emission Spectrometer.

The Thermal Emission Spectrometer spectra of low albedo surface materials suggests that a four to one mixture of pyroxene to plagioclase, together with about a 35 percent dust component provides the best fit to the spectrum. Qualitative upper limits can be placed on the concentration of carbonates (<10 percent), olivine (<10 percent), clay minerals (<20 percent), and quartz (<5 percent) in the limited regions observed. Limb observations in the northern hemisphere reveal low-lying dust hazes and detached water-ice clouds at altitudes up to 55 kilometers. At an aerocentric longitude of 224 degrees a major dust storm developed in the Noachis Terra region. The south polar cap retreat was similar to that observed by Viking.

Viking infrared thermal mapper.

The infrared thermal mapper (IRTM) was designed to measure the emitted and reflected radiance of Mars. Carried by the Viking Orbiter, the IRTM contains four small Cassegrainian telescopes which each image the same, seven circular areas. There is a total of twenty-eight channels in four surface and one atmospheric thermal bands from 6 microm to 30 microm and a broad solar reflectance band. All channels are sampled simultaneously, using the spacecraft scanning capability to map the radiance over small and large areas of the planet. All channels use thermopile detectors; spectral passbands are determined by a combination of interference filters, detector lense materials, antireflection coatings, and restrahlen optics.

Infrared radiometer for the pioneer 10 and 11 missions to jupiter.

Pioneer 10 has successfully encountered Jupiter and several of its satellites. The two-channel infrared radiometer used to obtain data relating to thermal properties of the planet and its atmosphere is described. The instrument features a body-fixed, 7.62-cm diam aperture Cassegrainian telescope with reststrahlen filters defining the 14-microm to 25-microm and 30-microm to 56-microm bands. Detectors are 88-junction evaporated thin-film thermopiles. Stringent weight constraints of 2 kg dictated all-beryllium construction. Power Consumption was 1.2 W.