• Papers

Using Range Observations of Spacecrafts Viking-1, Viking-2, Mariner-9 for Improvement of Orbital Elements of Planets and Parameters of Mars Rotation

Pitjeva E. V.

Proceedings of the 3rd International Workshop on Positional Astronomy and Celestial Mechanics, Alvaro Lopez Garcia, Eleonora I. Yagudina, Maria J. Martinez Uso, Alicia Cordero Barbero (Eds), Universitat de Valencia, Observatorio astronomico, 583-589 (1996)

Keywords: range observation of spacecrafts, ephemerides of planets, parameters of Mars rotation

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The extremely precise observations of spacecraft VIKING-1, VIKING-2 (1972-1982), MARINER-9 (1971-1972) were used for improvement of orbital elements of Mars and Earth and parameters of Earth rotation. The ranging observations near conjunction were corrected for the solar corona with simultaneous determination of parameters of corona model. These range data were combined with radar observations made at Haystack and Goldstone in 1971 (corrected for topography of Mars) to improve orbital elements of Mars and Earth. The precision of the least-squares adjustment is rather high, for example formal standard deviations of semi-major axis of Mars and Earth were 0."000004 for daM/aM and 0."000002 for daE/aE. Tracking data from planet landers allows to study precession and nutation of the spin axis that would provide a better understanding of planet geophysics. In the present work the rate of Mars rotation, the mean node and inclinations of the martian equator upon the mean orbit, their variations and Mars precession were improved from VIKING landers observations.