Increasing ADR effectiveness via an altitude-shell-dependent removal approach

The aim of this work is to investigate a new approach that can increase the Active Debris Removal (ADR) effectiveness regardless of the boundary conditions and the evolution of the Low Earth Orbit (LEO) population. This study use the Model to Investigate control Strategies for Space Debris (MISSD), developed at Southampton University. This statistical model uses a source-sink approach whereby new objects are added by launches, explosions, and collisions, while the atmospheric drag, ADR and Post-Mission Disposal (PMD) are removal mechanisms. A proportional controller applied to parameters associated with ADR represents the main novelty of this model. It is capable of emulating different removal principles (such as removing only rocket bodies or only inactive payloads) in each of the altitude shells in which the LEO region is divided. Through its application, several strategies for preventing (or limiting) the growth of the LEO population) are investigated and compared. Several test were performed with various number of removal and compliance level with PMD measures (0%, 30%, 60%, and 90%). The results indicate that a higher compliance with PMD guidelines achieve a lower orbital population (over a 200-yr timeframe) compared to using ADR strategies but with lower PMD compliance. Nevertheless, even with a wide adoption of PMD measures, the LEO population will increase and therefore the ADR technology presents a possible solution to stabilise the population and reduce the collision risk in specific LEO regions. In particular, the effect of removing one rocket body is comparable to removing two inactive spacecraft.