The increasing risk of space debris impact on Earth: case studies, potential damages, international liability framework and management systems

Since the beginning of space colonization, the number of space objects in orbit around the Earth has increased exponentially. It is currently estimated that around 15,000 satellites or other types of space vehicles are orbiting from the lower (LEO or above the stratosphere up to 10,000 km from Earth) to the higher (GEO or more than 10,000 km from Earth) orbital planes, for a total mass of more than 5000 tons. Consequently, uncontrolled space “debris” is produced for a total of 150 million pieces, from submillimetric items (propellant dust, paint flakes) to golf ball sizes and above (20,000). Besides the risks of collision with flying space vehicles, there is now growing concern for Earth impacts, since debris, by definition, is uncontrolled and may survive atmospherical re-entry friction falling almost anywhere when eventually reattracted by gravity. US NASA and NORAD statistics account for almost 17,000 large and small debris that have fallen until 2000, and 1 piece of debris a day is falling as a current average. This study aims at describing the framework for damage liability according to the International Treaty on Outer Space and its accessory protocols, giving an overview of the cases happened so far and the outlook for the future, together with examples of insurance models for damage coverage and mitigation systems (route diagnostics, radar surveillance, onboard protection, etc.)