With the advent of the New Space era and the large-scale deployment of mega-constellations, the congestion of the low Earth orbit (LEO) space environment is increasing rapidly. In this paper, we quantitatively analyze the changes in LEO object density by altitude (50 km bins) from 1957 to 2025 using CelesTrak Satellite catalog (SATCAT) data (68,188 registered objects), and empirically demonstrate the practical impact of increasing congestion through Korea Aerospace Research Institute (KARI)’s 2025 satellite collision risk management operational data 455,863 conjunction data message (CDMs), 67,077 conjunction events. The analysis confirms that the 450–500 km altitude band is the most congested region with 6,338 objects, representing a more than 100-fold increase compared to 2015. Of the 208 alert-level events in 2025, 90.4% involved active payloads, confirming that the primary source of collision risk is shifting from debris to operational satellites. The conjunction event frequency of KARI LEO satellites shows a strong correlation with orbital altitude congestion, with satellites at 450–550 km experiencing more than five times the events of a satellite at 685 km. Based on these findings, we propose short-term and mid-to-long-term directions for collision risk management technologies, including machine learning (ML)-based automatic risk classification, digital twin-based integrated platforms, and space traffic management (STM) data sharing frameworks.
Jaedong Seong (Fri,) studied this question.