DYNAMIC ATMOSPHERIC EFFECTS UPON SATELLITE MOTION AND SATELLITE LIFETIME.
AEROSPACE CORP EL SEGUNDO CALIF
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Various model atmospheres are examined with regard to their effect upon the prediction of 1 satellite lifetime and 2 satellite orbit ephemerides. High speed computer results based upon the empirical dynamic model atmospheres of Paetzold and Jacchia are compared to corresponding results based on the ARDC 1959 static model atmosphere that has been in wide use in the United States. For the sake of completeness the atmospheric density profiles and dynamic models of Nicolet, King-Hele, Harris, and Priester are described together with static models such as CIRA 1961 and the U. S. Standard Atmosphere,. 1962. It is shown for near-earth altitude regions that predicted values of satellite lifetime may differ by a factor of 30 depending upon whether use is made of a static or a dynamic model atmosphere. This is primarily due to the fact that the large long-term influence of the 11-year solar cycle can introduce appreciable differences between static models, which are patterned after a given time period, and dynamic models, which vary with time. In the case of satellite ephemeris prediction, short-term effects such as those due to geomagnetic disturbances which are not accountable with static models become important as well. It is shown that the predicted in-track position of a typical satellite may be in error by approximately 10 kilometers 5 nautical miles after a 12-hour time period if an intense but unpredictable magnetic storm occurs in that interval. Author