A space-based debris cataloguing system for the new space era

Abstract

Over the past decades, space activities have increased significantly, giving rise to a growing threat: space debris. Today, over 28,160 objects are tracked by the U.S. Space Surveillance Network, primarily those larger than 10 cm in low-Earth orbit (LEO). However, 100,000s of debris below this size remain largely untracked, despite being a major cause of missionending damage. Most Space Situational Awareness (SSA) systems can catalogue objects down to 10 cm, but conjunction assessments and collision avoidance manoeuvres only address less than 1% of the impact risk. Meanwhile, spacecraft remain vulnerable to catastrophic, undetected collisions with debris between 0.1 and 10 cm. Hence, mitigating existing risks is a critical priority for the space sector. The growing importance of SSA highlights the need to track centimetre-sized debris. This paper presents a Phase 0 feasibility study of the Threat and Hazard Evaluation for Intelligent Awareness (THEIA) mission, a space-based system designed to address this observation gap. THEIA employs a dual-payload constellation of 12-unit CubeSats, with radar satellites performing initial orbit determination and optical satellites enabling precise orbit determination. The baseline configuration, consisting of 15 radar satellites and 108 optical satellites in complementary orbital planes, achieves approximately 26% catalogue completeness of 5–10 cm debris within five years. Although below the 80% target, the study demonstrates the technical feasibility of centimetre-class debris tracking within CubeSat constraints and confirms the potential for scalable small-satellite architectures. The financial analysis, based on a discounted cash flow model, indicates strong economic viability with a positive net present value exceeding =C1 billion under hybrid funding assumptions. However, limitations remain in radar payload performance, constellation coverage, and dynamical modelling, which considered only simplified perturbations. Future work should include higher-fidelity modelling, collision risk assessment for observer satellites, shielding and avoidance strategies, and the evaluation of larger platforms to increase radar performance and catalogue completeness. Overall, THEIA demonstrates that centimetre-class debris cataloguing is both technically and economically feasible, providing a foundation for safer and more sustainable space operations.