Short-term space occupancy and conjunction filter

Conjunction analysis (CA) for resident space objects (RSOs) is essential for preventing collisions in an increasingly crowded orbital environment and preserving the operational integrity of satellites. A first and fundamental step in the CA process is to estimate the range of altitudes that each object can occupy throughout an operational screening time of, typically, a few days. In this paper, a method is proposed to analytically evaluate such range of altitudes in a zonal problem model and for a time horizon of generic duration thereby generalizing the concept of space occupancy (SO) introduced in a recent work. The proposed method is exploited to construct a new conjunction filter that considerably improves the classical apogee-perigee filter routinely employed in CA. The effectiveness of the new filter is assessed in a low-Earth orbit (LEO) scenario using a high-fidelity perturbation model across a broad spectrum of orbits and conjunction geometries.