Analysis of the variation in eccentricity of the orbit of Cosmos 185 rocket, 1967-104B

The orbit of Cosmos 185 rocket (1967-104B) has been determined at 114 epochs between 29 January 1980 and 13 May 1986. One hundred and fourteen values of eccentricity have been determined, spanning a complete cycle of the argument of perigee, with standard deviations (S.D.s) as low as 0.000001 corresponding to an accuracy of 7 m in perigee height. Corrected for the effects due to lunisolar perturbations, solid-Earth tides, solar radiation pressure and air drag, the analysis has indicated an amplitude of oscillation in eccentricity equivalent to almost 30 km in perigee height and provided a corresponding equation of condition which has been used in a determination of the gravitational field of the Earth.