Effect of the Semi-Synchronous Orbit Protected Region on the MEO Debris Environment (Invited)

Abstract

A protected region about semi-synchronous orbit (SSO) is included in United States (U.S.) Government orbital debris mitigation policy. SSO is the mission orbit of the U.S. Global Positioning System (GPS) in medium Earth orbit (MEO). In contrast, international debris mitigation guidelines do not contain protected regions about any MEO navigation constellations. A study was performed to assess the effect of the U.S. SSO protected region on the future MEO debris environment. The study used a simulation process developed by The Aerospace Corporation (Aerospace) called the Aerospace Debris Environment Projection Tool (ADEPT). The study results indicate that the primary mitigation effect of the SSO protected region is not in keeping objects out of the SSO protected region itself, but rather in reducing usage of long-term stable MEO storage disposal orbits. While the U.S. SSO protected region indirectly reduces collisional debris in MEO from U.S. satellites and rocket bodies, the reduction is small compared to the amount of collisional debris resulting from non-U.S. usage of long-term stable MEO storage disposal orbits. Reducing world-wide usage of long-term stable MEO storage disposal orbits and configuring MEO constellation disposal orbits to decay via Sun-Moon perturbations may be more effective approaches at reducing MEO debris risk than the U.S. SSO protected region.