Accession Number:

AD0620053

Title:

A SIMPLE EXPLANATION FOR THE SEMI-ANNUAL EFFECT APPEARING IN SATELLITE ORBITAL DECAY DATA,

Descriptive Note:

Corporate Author:

LOCKHEED MISSILES AND SPACE CO SUNNYVALE CALIF

Personal Author(s):

Report Date:

1965-08-01

Pagination or Media Count:

33.0

Abstract:

A semi-annual effect was found by Paetzold and Zschorner in satellite orbital decay data. They interpreted the cause of this effect to be a world-wide semi-annual density variation in the upper atmosphere. However, the analysis presented in this article reveals that this effect is correlated definitely with the difference in latitude between satellite perigee and the subsolar point. This relation is explained by inferring that the prominant minimums in orbital decay values near the solstices result from a marked latitude variation in density existing in the winter hemisphere at this time, with the density at the winter pole indicated to be much lower than at the subsolar point or equator. A contributing factor is that the perigee of a given satellite, which changes latitude regularly from north to south of the subsolar point and vice versa, reaches its maximum distance north or south of the subsolar point near the solstices. This hypothesis is able to explain qualitatively all of the observed features of the semi-annual effect. More important, it strongly indicates the existence of a strong latitudinal density variation in the winter hemisphere. Author

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Distribution Statement:

APPROVED FOR PUBLIC RELEASE