On a general apogee formula for the disposal of satellites and rocket bodies below the geosynchronous protected region

The geosynchronous orbital region (GEO) is heavily used by satellites. To avoid the proliferation of space debris in this unique orbital environment, space debris mitigation guidelines define a protected region around the orbit and recommend disposal strategies that avoid long-term interference. For satellites operating in the GEO-protected region, a well-known formula was established that defines a minimum-perigee altitude, for a given eccentricity, that avoids drifting back into this regime after the end of the mission. This formula, found in the IADC space debris mitigation guidelines, suggests disposal in near-circular, long-term 'stable' orbits above the GEOprotected region, whereby the altitude of perigee is beyond 235 km plus a factor accounting for the solar radiation pressure perturbations. Recently, an extension of this formula that also accounts for the inclination has been suggested. With the advent of direct launch into GEO, whereby either a rocket body or satellite is left in an orbit below the protected region, the natural question arises whether a similar formula can be found for the apogee of disposal orbits below the protected region. The presented work investigates the dynamics of the sub-GEO region and establishes and validates an upper-apogee-difference limit for a time span of at least 100 years. Moreover, the practical implication of such a strategy on the delta-V budget of a mission is assessed. (c) 2023 COSPAR. Published by Elsevier B.V. All rights reserved.