Look Out for the Little Ones: On the Long-Term Impact of Debris Size Distribution on Breakup

Abstract This paper investigates the long-term effects of satellite breakup on the evolutionary growth of debris in the Low Earth Orbit (LEO) environment. We use a set of stochastic simulations of source-sink models to explore how collisional cascade can happen (or not) due to debris objects from meter scales down to 1 mm. We model two distinct effects from two classes of debris: (1) lethal debris cause catastrophic breakup of satellites upon collisions, and (2) marginally lethal debris do not cause catastrophic breakup, but can turn active maneuverable satellites into derelict ones. We show that the future environment sensitively depends on the relative proportion of the two classes of debris produced by each breakup event. In particular, a large amount of marginally lethal debris can introduce a large number of mission-ending collisions, creating a large population of derelict satellites that ultimately become a source of catastrophic collisions. We can dramatically decrease future collisions by lowering the observable length scale of debris below the length scale characteristic of debris that causes lethal collisions, ℓLethal, and allowing active satellites to maneuver and perform collision avoidance.