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Optical Scanner

NSSDCA ID: 1959-001A-01

Mission Name: Vanguard 2
Principal Investigator:Mr. William G. Stroud


The optical scanner experiment was designed to obtain cloud-cover data between the equator and 35 to 45 deg N latitude. As the satellite circled the earth, two photocells located at the focus of two optical telescopes aimed in diametrically opposite directions, measured the intensity of sunlight reflected from clouds (about 80%), from land masses (15 to 20%), and from sea areas (5%). The satellite motion and rotation caused the photocells to scan the earth in successive "lines." Separate solar batteries turned on a recorder only when the earth beneath the satellite was in sunlight and about 50 min of data per orbit were obtained. The measured reflection intensities were stored on tape. Ground stations interrogated the satellite by signaling its command receiver, which caused the entire tape to be played back in 60 s. The tape was then erased and rewound. Experiment equipment functioned normally, but data were poor because of an unsatisfactory satellite spin axis orientation.

Alternate Names

  • Vanguard2/OpticalScanner

Funding Agency

  • Unknown (United States)


  • Earth Science: Atmospheric Dynamics

Additional Information

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



NameRoleOriginal AffiliationE-mail
Mr. William G. StroudPrincipal InvestigatorNASA Goddard Space Flight Center
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