Orbital Regression of Synchronous Satellites Due to the Combined Gravitational Effects of the Sun, the Moon, and the Oblate Earth
Dec 31, 1966
An investigation of the behavior of a synchronous (24-hour) satellite as affected by the triaxiality of the earth and the gravitational attractions due to the sun and moon. It is shown that, because of gravitational effects attributable to the out-of-roundness of the earth, station-keeping propulsion of as much as 17 ft/sec/yr would be required to establish a synchronous satellite at a given longitude above the earth's equator. The authors indicate that the perturbing effects of the sun and moon are (1) to displace the satellite within its orbital plane by a maximum of 45 miles and (2) to produce a rotation of the orbital plane away from the equatorial plane at a rate of about 0.85 deg/yr. If this latter effect needs to be corrected for proper operation of the system, it would require an additional propulsion of 150 ft/sec/yr.