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Experiment D005: Star occultation navigationThe usefulness of star occultation measurements for space navigation and the determination of a horizon density profile which could be used to update atmospheric models for horizon-based measurement systems were studied. The time of occultation of a known star by a celestial body, as seen by an orbiting observer, determines a cylinder of position, the axis of which is the line through the star and the body center, and the radius of which is equal to the occulting-body radius. The dimming percentage, with respect to the altitude of this grazing ray from the star to the observer, is a percentage altitude for occultation. That is, the star can be assumed to be occulted when it reaches a predetermined percentage of its unattenuated value. The procedure used was to measure this attenuation with respect to time to determine the usefulness of the measurements for autonomous space navigation. In this experiment, the crewmembers had to accomplish star acquisition, identification, calibration, and tracking. Instrumentation was required only for measurement of the relative intensity of the star as it set into the atmosphere.
Document ID
Document Type
Silva, R. M.
(Air Force Systems Command Wright-Patterson AFB, OH, United States)
Jorris, T. R.
(Air Force Systems Command Wright-Patterson AFB, OH, United States)
Vallerie, E. M., III
(NASA Manned Spacecraft Center Houston, Tex., United States)
Date Acquired
August 6, 2013
Publication Date
September 1, 1971
Publication Information
Publication: NASA. Manned Spacecraft Center The Gemini Program: Phys. Sci. Expt. Sum.
Subject Category
Accession Number
Distribution Limits
Work of the US Gov. Public Use Permitted.
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