Managing the Orbital Debris Hazard Long-Term: Space Sustainability

The orbital debris environment, especially in low Earth orbit (LEO), is dynamic and concerning. The accumulation of abandoned massive derelicts (e.g., rocket bodies and non-operational payloads), clouds of fragments from breakup events, and thousands of new smallsats, often deployed in large constellations, creates challenges for achieving space sustainability. The interdependency of these three main constituents of LEO provides a compelling means to examine emerging collision risks. Technical terms and equations used to quantify collision risk and prioritize risk reduction measures are provided. The probability of collision for specific encounters for operational spacecraft are provided by Conjunction Data Messages (CDMs) as the key currency for space traffic coordination. The annual probability of collision to operational spacecraft from clouds of fragments depicts the primary statistical collision risk posed to spacecraft. The collision rate within clusters of massive derelicts abandoned decades ago is shown to characterize the primary debris-generating potential in LEO.