Conceptualizing thresholds for effective active debris removal in Low Earth Orbit

The rapid growth of orbital debris in the Low Earth Orbit (LEO) poses an escalating risk to space operations, with existing mitigation proving insufficient to prevent long-term instability. This study models debris population dynamics in the 500–600 km LEO under current FCC 5-year deorbit rules and varying levels of Active Debris Removal (ADR). Using publicly available orbital catalogs and a collision-risk proxy based on object density, cross-section, and relative velocity, simulations depict debris growth and collision risk trajectories under a 30-year period and various scenarios. Results indicate that removal of ∼60 large objects (>10 cm) per year is the threshold at which debris growth becomes negative and collision risk declines. This value is scenario-dependent and is presented as an illustrative threshold under controlled assumptions rather than a robust or universal quantitative value. The primary contribution of this study is to demonstrate the existence of a minimum viable ADR regime, which can provide conceptual guidance for debris mitigation policy.