NSSDCA ID: 1967-020A-04
Mission Name: OSO 3The earth albedo experiment measured the spectral distribution of sunlight reflected from the earth in the 0.32- to 0.78-micron range to enable the study of the effect of ultraviolet radiation on thermal control coatings on near-earth satellites. Six photomultipliers fitted with interference filters permitted measurements to be taken at wavelengths of 0.32, 0.37, 0.45, 0.54, 0.67, and 0.78 microns. Each channel had separate apertures for calibration and the albedo radiation measurement. The solar aperture was aligned perpendicular to the spacecraft axis of rotation so that sunlight entered during each revolution when the experiment was pointed at the sun. Sunlight entering the albedo aperture was rejected by an aluminized mirror, which focused the sunlight out of the aperture. Thus, unwanted radiation was rejected when the experiment was calibrated. The albedo aperture had a cone angle of 5 deg and was set at a 70-deg angle from the axis of rotation so that only albedo radiation could reach the photomultiplier directly. The measured intensity of reflected sunlight for any one channel was within 5 percent of the observed value. The experiment was a success, and good data were obtained for 65 orbits (until March 17, 1967). On this date, the instrument stopped as a result of the failure of the low voltage transistor on the A/D convertor. For a complete description of the experiment along with preliminary results, see 'Results from the Thermal Control Cratings Experiment on OSO-III,' by J. P. Millard, presented at the Third Thermal Physics Conference, Los Angeles, CA, June 1968 (pages 68 to 79 in conference proceedings).
Mass: 9 kg
Power (avg): 0.5 W
Questions and comments about this experiment can be directed to: Coordinated Request and User Support Office
Name | Role | Original Affiliation | |
---|---|---|---|
Mr. John C. Arvesen | General Contact | NASA Ames Research Center | |
Mr. Gilbert G. Robinson | Other Investigator | NASA Ames Research Center | |
Mr. Carr B. Neel, Jr. | Principal Investigator | NASA Ames Research Center |