Long-term perigee height variations of GEO disposal orbits - A revisit

Earlier investigations suggest small initial eccentricity for improved orbit stability of the disposal orbits at super synchronous altitudes. Results of a recent study show that the IADC guideline for disposal of objects in geosynchronous orbits (GEO), which is plus no less than 235 km for perigees of disposal orbits, is appropriate if the initial eccentricity is less than 0.005. According to the ground operations of several GEO missions, the current communications satellites are capable of achieving a final eccentricity of 0.0005 or better for their disposal orbits. This study revisits the problem based on more realistic orbit insertion capability and a high-precision orbit propagation tool, TRACE. Results of analytical investigation and 100-year numerical integration led to two important findings: 1) long-term stability of GEO disposal orbits can be further improved by keeping perigee sun-pointing and initial eccentricity less than 0.0005, 2) the IADC guideline is adequate for maintaining a minimum perigee at 250 km higher than GEO if condition 1) is followed. Long-term perigee variations of inactive objects near GEO altitude were examined in this study.